WO2021228904A1

WO2021228904A1 - Neutralizing antibodies binding to the spike protein of sars-cov-2 suitable for use in the treatment of covid-19, compositions comprising the same and uses thereof

Info

Publication number: WO2021228904A1
Application number: PCT/EP2021/062558
Authority: WO
Inventors: Marit Johanna VAN GILS; Rogier Willem SANDERS; Karlijn VAN DER STRATEN; Philip Johannes Marie BROUWER; Thomas Gerardus CANIELS; Godelieve Johannes DE BREE
Original assignee: Academisch Medisch Centrum
Priority date: 2020-05-11
Filing date: 2021-05-11
Publication date: 2021-11-18

Abstract

The present invention is related to human antibodies and antigen-binding fragments of human antibodies that bind to the spike protein of the SARS-CoV-2 virus which is the cause of coronavirus disease 2019 (COVID-19), and therapeutic and diagnostic methods of using those antibodies.

Description

neutralizing antibodies binding to the spike protein of SARS-CoV-2 suitable for use in the treatment of COVID-19, compositions comprising the same and uses thereof

FIELD OF THE INVENTION

The present invention is related to human antibodies and antigen-binding fragments of human antibodies that bind to the spike protein of the SARS-CoV-2 virus which is the cause of coronavirus disease 2019 (COVID-19), and therapeutic, prophylactic and diagnostic methods of using those antibodies.

BACKGROUND

The rapid emergence of three novel pathogenic human coronaviruses in the past two decades has caused significant concerns, with the latest severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) being responsible for over three million infections and 230.000 deaths worldwide as of May 1, 2020 (1). The coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is characterized by mild flu-like symptoms in the majority of patients. However, severe cases can present with bilateral pneumonia which may rapidly deteriorate into acute respiratory distress syndrome (2). With such a high number of people being infected worldwide and no proven curative treatment available, health care systems are under severe pressure. Safe and effective treatment and prevention measures for COVID-19 are therefore urgently needed.

During the outbreak of SARS-CoV and Middle Eastern respiratory syndrome coronavirus (MERS-CoV), plasma of recovered patients containing neutralizing antibodies (NAbs) was used as a safe and effective treatment option to decrease viral load and reduce mortality in severe cases (3, 4). Recently, a small number of COVID-19 patients treated with convalescent plasma, showed clinical improvement and a decrease in viral load within the following days (5). An alternative treatment strategy is offered by administering purified monoclonal antibodies (mAbs) with neutralizing capacity. mAbs can be thoroughly characterized in vitro and easily expressed in large quantities. In addition, due to the ability to control dosing and composition, mAb therapy improves the efficacy over convalescent plasma treatment and prevents the potential risks of antibody-dependent enhancement (ADE) from non- or poorly neutralizing antibodies present in plasma which consists of a polyclonal mixture (6). Recent studies with patients infected with the Ebola virus highlight the superiority of mAb treatment over convalescent plasma treatment (7, 8). Moreover, mAb therapy has been proven safe and effective against influenza virus, rabies virus, and respiratory syncytial virus (RSV) (9-11).

The main target for NAbs on coronaviruses is the spike (S) protein, a homotrimeric glycoprotein that is anchored in the viral membrane. Recent studies have shown that the S protein of SARS-Cov-2 bears considerable structural homology to SARS-CoV, with the S protein consisting of two subdomains: the N-terminal S1 domain, which contains the receptor- binding domain (RBD) for the host cell receptor angiotensin converting enzyme-2 (ACE2) and the S2 domain, which contains the fusion peptide (12, 13). Similar to other viruses containing class-1 fusion proteins (e.g. HIV-1, RSV and Lassa virus), the S protein undergoes a conformational change upon host cell receptor binding from a prefusion to postfusion state enabling merging of viral and target cell membranes (14, 15). When expressed as recombinant soluble proteins, class- 1 fusion proteins generally have the propensity to switch to a postfusion state. However, most NAb epitopes are presented on the prefusion conformation (16-18). The recent successes of isolating potent neutralizing antibodies against HIV-1 and RSV using stabilized prefusion glycoproteins reflect the importance of using the prefusion conformation for isolation and mapping of mAbs against SARS-CoV-2 (19, 20).

So far, the number of identified mAbs that neutralize SARS-CoV-2 has been limited. Early efforts in obtaining NAbs focused on re-evaluating SARS-CoV-specific mAbs isolated after the 2003 outbreak, that might cross-neutralize SARS-CoV-2 (21, 22). Although two mAbs were described to cross-neutralize SARS-CoV-2, the majority of SARS-CoV NAbs did not bind SARS-CoV-2 S protein or neutralize SARS-CoV-2 virus (12, 21-23). More recently, the focus has shifted from cross-neutralizing SARS-CoV NAbs to the isolation of novel SARS- CoV-2 NAbs from recovered COVID-19 patients (24, 25). S protein fragments containing the RBD have yielded multiple RBD-targeting NAbs that can neutralize SARS-CoV-2 (24, 25). In light of the rapid emergence of escape mutants in the RBD of SARS-CoV and MERS, monoclonal NAbs targeting other epitopes than the RBD are a welcome component of any therapeutic antibody cocktail (26, 27).

Thus far, there has been no vaccine or therapeutic agent to prevent or treat COVID-19 infection. In view of the continuing threat to human health, there is an urgent need for preventive and therapeutic antiviral therapies for COVID-19 control. Fully human antibodies that specifically bind to COVID-19 spike protein with high affinity and inhibit virus infectivity could be important in the prevention and treatment of COVID-19 infection. BRIEF SUMMARY OF THE INVENTION

The present invention provides antibodies and antigen-binding fragments thereof that bind to the SARS-CoV-2 spike protein. The antibodies of the present invention are useful, inter alia, for inhibiting or neutralizing the activity of the SARS-CoV-2 spike (abbreviated to SARS-CoV- 2-S herein) protein. In some embodiments, the antibodies are useful for blocking binding of the virus to its host cell receptor angiotensin-converting enzyme 2 (ACE2) and for preventing the entry of a SARS-CoV-2 virus into host cells. In some embodiments, the antibodies function by inhibiting the cell-to-cell transmission of the virus. In certain embodiments, the antibodies are useful in preventing, treating or ameliorating at least one symptom of SARS- CoV-2 infection in a subject. In certain embodiments, the antibodies may be administered prophylactically or therapeutically to a subject having or at risk of having SARS-CoV-2 infection. In certain embodiments, the antibodies are useful in diagnostics.

The antibodies of the invention can be full-length (for example, an lgG1 or lgG4 antibody) or may comprise only an antigen-binding portion (for example, a Fab, F(ab')2 or scFv fragment), and may be modified to affect functionality, e.g., to increase persistence in the host or to eliminate or enhance effector functions (Reddy et al., 2000, J. Immunol. 164:1925-1933). In certain embodiments, the antibodies may be bispecific or trispecific.

In a first aspect, the present invention provides an isolated antibody or antigen-binding fragment thereof that binds to the SARS-CoV-2 spike protein. Preferably, said antibody is a human antibody. Preferably, said antibody is a recombinant antibody. In a preferred embodiment, said antibody is a fully human monoclonal antibody. The antibody or antigen binding fragment thereof according to the invention binds to an epitope within the receptor binding domain (RBD) of the spike protein of SARS-CoV-2, or the N-terminal domain (NTD), which comprise residues 15-681 of the Spike protein. In certain preferred embodiments, said antibody or antigen-binding fragment according to the invention does not bind to SARS-CoV. Such antibodies are suitable for diagnostic purposes. In a preferred embodiment, said antibody or antigen-binding fragment thereof according to the invention is capable of neutralizing the SARS-CoV-2 virus or blocking its entry into a host cell. In another preferred embodiment, said antibody or antigen-binding fragment thereof according to the invention is capable of neutralizing both the SARS-CoV and SARS-CoV-2 virus or blocking their entry into a host cell.

Preferably, said antibody or antigen-binding fragment thereof has one or more of the following characteristics: a. is a fully human monoclonal antibody; b. neutralizes SARS-CoV-2 infectivity wherein the SARS-CoV-2 comprises an isolate of the virus (German isolate; GISAID ID EPIJSL 406862; European Virus Archive Global #026V-03883); c. neutralizes SARS-CoV-2 infectivity of human host cells with IC50 less than 4.5 pg/ml, as measured in a pseudovirus neutralization assay; d. interacts with one or more amino acid residues in the receptor binding domain of the SARS-CoV-2 spike protein selected from amino acid residues 319 to 529 of SEQ ID NO: 669; e. binds to SARS-CoV-2 spike protein with a dissociation constant (KD) of less than 175 nM as measured in a surface plasmon resonance assay; f. inhibits binding of SARS-CoV-2 spike protein to ACE2 by more than 40%, as measured in a bio-layer interferometry assay; g. is a bi-specific antibody comprising a first binding specificity to a first epitope in the receptor binding domain of SARS-CoV-2 spike protein and a second binding specificity to a second epitope in the receptor binding domain of SARS-CoV-2 spike protein wherein the first and second epitopes are distinct and non-overlapping.

Preferably, said inhibition or neutralization in step b) reduces infectivity by at least 25%, more preferably 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%. Preferably, said neutralization in step b) is with an IC50 less than 4.5 pg/mL. More preferably, said antibody or antigen binding fragment thereof has an IC50 equal or lower than 4.4, 4.0, 3.7, 3.2, 1.8, 1.3, 0.52, 0.31, 0.18, 0.097, 0.072, 0.053, 0.036, 0.034, 0.029, 0.021, 0,008 (pg/mL).

Preferably, said inhibition or neutralization in step c) reduces infectivity of human host cells by at least 60%, more preferably 65%, 70%, 75%, 80%, 85%, 90%, 95% or 100%.

Preferably, said neutralization or inhibition in step b) is with an IC50 equal to or less than 2.8, 0.76, 0.25, 0.17, 0.048, 0.04, 0.010, 0.007 pg/mL.

In certain embodiments, the antibodies neutralize the infectivity of SARS-CoV-2 viruses in Vero-E6 cells. In some embodiments, the antibodies inhibited more than 90% binding of SARS-CoV-2 on human host cells in plaque reduction neutralization test, e.g., as shown in Example 5, or a substantially similar assay.

Exemplary anti-SARS-CoV-2-S antibodies of the present invention are listed in Table 2 herein. Table 2 sets forth the amino acid sequence identifiers of the heavy chain variable regions (HCVRs), light chain variable regions (LCVRs), heavy chain complementarity determining regions (HCDR1, HCDR2 and HCDR3), and light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) of exemplary anti-SARS-CoV-2-S antibodies. In Table 3, sequences of the CDRL2 sequences of the antibodies listed in Table 2 are listed. All other sequences have been included in the sequence list which makes part of this document.

In a preferred embodiment, said HCVR comprises an amino acid sequence selected from any of the HCVR amino acid sequences listed in Table 2, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity thereto.

In a preferred embodiment, said LCVR comprises an amino acid sequence selected from any of the LCVR amino acid sequences listed in Table 2, or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity thereto.

In a preferred embodiment, said HCDR1 comprises an amino acid sequence selected from any of the HCDR1 amino acid sequences listed in Table 2 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In a preferred embodiment, said HCDR) comprises an amino acid sequence selected from any of the HCDR2 amino acid sequences listed in Table 2 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In a preferred embodiment, said CDR3 (HCDR3) comprises an amino acid sequence selected from any of the HCDR3 amino acid sequences listed in Table 2 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In a preferred embodiment, said LCDR1 comprises an amino acid sequence selected from any of the LCDR1 amino acid sequences listed in Table 2 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In a preferred embodiment, said LCDR2 comprises an amino acid sequence selected from any of the LCDR2 amino acid sequences listed in Table 2 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In a preferred embodiment, said LCDR3 comprises an amino acid sequence selected from any of the LCDR3 amino acid sequences listed in Table 2 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity. In a preferred embodiment, said antibody or antigen-binding fragment thereof according to the invention, wherein said antibody:

(a) comprises three heavy chain complementarity determining regions (CDRs) (HCDR1, HCDR2 and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) contained within an HCVR/LCVR amino acid sequence listed in Table 2. Preferably, said HCVR/LCVR amino acid sequence pair is selected from the group consisting of the SEQ ID Nos: 1/5, 9/13, 17/21, 25/29, 33/37, 41/45, 49/53, 57/61, 65/69, 73/77, 81/85, 89/93, 97/101, 105/109, 113/117, 121/125, 129/133, 137/141, 145/149, 153/157, 161/165, 169/173, 177/181, 185/189, 193/197, 201/205, 213/209, 217/221,

225/229, 233/237, 241/245, 249/253, 257/261, 265/269, 273/277, 281/285, 289/293,

297/301, 305/309, 313/317, 321/325, 329/333, 337/341, 345/349, 353/357, 361/365,

369/373, 381/385, 389/393, 397/401 , 405/409, 413/417, 421/425, 429/433, 437/441,

445/449, 453/457, 461/465, 469/473, 477/481, 485/489, 493/497, 501/505, 509/513,

517/521, 525/529, 533/537, 541/545, 549/553, 557/561, 565/569, 573/577, 581/585,

589/593, 597/601, 605/609, 613/617, 621/625, 629/633, 637/641, 645/649, 653/657 and 661/665;

(b) competes for binding to SARS-CoV-2-S with an antibody or antigen-binding fragment of (a); or

(c) binds to the same epitope as an antibody or antigen-binding fragment of (a).

In preferred embodiments, the HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 17/21, 89/93, 121/125, 137/141, 161/165, 169/173, 193/197, 225/229, 241/245, 249/253, 265/269, 297/301, 313/317, 329/333, 345/349, 369/373, 437/441,

501/505, 517/521 (e.g., 001_P1D6, 17/21), (e.g., 001_P1G11, 89/93), (e.g., 001_P2A8, 121/125), (e.g., 001_P2C1, 137/141), (e.g., 001_P2C9, 161/165), (e.g., 001_P2F7, 169/173), (e.g., 001_P3A1 , 193/197), (e.g., 002_P1C7, 225/229), (e.g., 002_P1D2, 241/245), (e.g., 002_P1D6, 249/253), (e.g., 002_P1E3, 265/269), (e.g., 002_P1H2, 297/301), (e.g., 002_P1H10, 313/317), (e.g., 002_P2A5, 329/333), (e.g., 002_P2C4, 345/349), (e.g., 002_P2H1 , 369/373), (e.g., 002_P3G9, 437/441), (e.g., 002_P4D8, 501/505), (e.g., 002_P5A10, 517/521). An advantage of these antibodies is that they have an IC50 value lower than 4,5 pg/mL in a pseudovirus assay.

In preferred embodiments, the HCVR/LCVR amino acid sequence pair is selected from SEQ ID NOs: 329/333 and 137/141. In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 17/21, 121/125, 137/141, 161/165, 169/173, 193/197, 241/245, 265/269, 329/333, 345/349, 437/441, 517/521 (e.g., 001_P1D6, 17/21), (e.g., 001_P2C1, 137/141), (e.g., 001_P2C9, 161/165), (e.g., 001_P2F7, 169/173), (e.g., 001_P3A1, 193/197), (e.g., 002_P1D2, 241/245), (e.g., 002_P1E3, 265/269), (e.g., 002_P2A5, 329/333), (e.g., 002_P2C4, 345/349), (e.g., 002_P3G9, 437/441), (e.g., 002_P5A10, 517/521). An advantage of these antibodies is that they have an IC50 value lower than 0.53 pg/mL in a pseudovirus assay.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 121/125, 137/141, 161/165, 169/173, 193/197, 265/269, 329/333, 345/349, 437/441, 517/521. An advantage of these antibodies is that they have an IC50 value lower than 0.19 pg/mL in a pseudovirus assay.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 137/141, 161/165, 169/173, 265/269, 329/333, 345/349, 517/521. An advantage of these antibodies is that they have an IC50 value lower than 0.06 pg/mL in a pseudovirus assay.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141, 265/269, 517/521, 161/165, 89/93, 121/125, 241/245, 345/349, 169/173 and 249/253. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141, 265/269, 517/521, 161/165, 89/93, 121/125 and 241/245. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 2.8 pg/mL.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141, 265/269, 517/521, 161/165, 89/93 and 121/125. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.76 pg/mL.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141, 265/269, 517/521, 161/165 and 89/93. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.25pg/mL. In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141, 265/269 517/521 and 161/165. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.17 pg/mL.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141, 265/269 and 517/521. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.048 pg/mL.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, 137/141 and 265/269. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.04 pg/mL.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 329/333, and 137/141. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.01 pg/mL.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 225/229 and 121/125. An advantage of these antibodies is that they neutralize both SARS-CoV and SARS-CoV-2 .

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 137/141, 517/521, 389/393, 469/473, 437/441, 121/125, 249/253, 369/373, 297/301, 225/229, 233/237, 289/293, 453/457, 573/577, 169/173, 397/401, 445/449, 501/505, 49/53, 321/325, 533/537, 629/633, 265/269, 153/157, 429/433, 565/569, 329/333, 213/209, 313/317, 201/205, 337/341, 405/409. An advantage of these antibodies is that they have a KD of 1 nM or less in a surface plasmon resonance assay.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 137/141, 517/521, 389/393, 437/441, 121/125, 249/253, 369/373, 297/301, 225/229, 453/457, 573/577, 397/401, 49/53, 629/633, 265/269, 565/569, 329/333, 313/317, 337/341, 461/465, 493/497, 241/245, 89/93, 73/77, 557/561, 345/349, 421/425, 621/625, 217/221, 57/61 , 653/657, 661/665. More preferably, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 137/141, 265/269, 329/333, 345/349, 517/521. An advantage is that these antibodies bind specifically to RBD of SARS-CoV-2. In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 1/5, 9/13, 41/45, 57/61, 65/69, 89/93, 137/141, 145/149, 153/157, 161/165, 169/173, 193/197, 201/205, 233/237, 241/245, 249/253, 265/269, 289/293,

297/301, 305/309, 313/317, 329/333, 337/341, 345/349, 369/373, 381/385, 389/393,

397/401, 405/409, 413/417, 429/433, 437/441, 445/449, 453/457, 469/473, 477/481,

509/513, 517/521, 525/529, 533/537, 549/553, 565/569, 573/577, 581/585, 613/617,

621/625, 629/633, 637/641, 653/657. An advantage of these antibodies is that they bind specifically to SARS-CoV-2 S and not to SARS-CoV-S.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 1/5, 9/13, 41/45, 49/53, 57/61, 65/69, 89/93, 121/125, 137/141, 145/149, 153/157, 161/165, 169/173, 193/197, 201/205, 213/209, 225/229, 233/237,

241/245, 249/253, 265/269, 289/293, 297/301, 305/309, 313/317, 321/325, 329/333,

337/341, 345/349, 353/357, 369/373, 381/385, 389/393, 397/401, 405/409, 413/417,

421/425, 429/433, 437/441, 445/449, 453/457, 461/465, 469/473, 477/481, 501/505,

509/513, 517/521, 525/529, 533/537, 549/553, 557/561, 565/569, 573/577, 581/585,

589/593, 605/609, 613/617, 621/625, 629/633, 637/641, 653/657, 661/665. An advantage of these antibodies is that they bind to SARS-CoV-2 S.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 49/53, 57/61, 73/77, 89/93, 121/125, 137/141, 241/245, 265/269, 297/301, 313/317, 329/333, 337/341, 345/349, 369/373, 389/393, 397/401, 437/441,

453/457, 517/521, 565/569, 573/577, 621/625, 629/633, 653/657. An advantage of these antibodies is that they bind specifically to SARS-CoV-2 RBD. In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 137/141, 265/269, 329/333, 345/349, 517/521. An advantage of these antibodies is that they bind specifically to SARS-CoV-2 RBD.

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 137/141, 265/269, 329/333, 437/441 and 517/521. An advantage is that these antibodies showed strong competition with ACE2 binding (see Table 7).

In another preferred embodiment, said HCVR/LCVR amino acid sequence pair is selected from one of SEQ ID NOs: 169/173.. An advantage is that these antibodies showed binding to NTD (See Example 7).

In a preferred embodiment, said antibody, or antigen-binding fragment thereof, comprises a set of six CDRs (i.e., HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3) contained within any of the exemplary anti-SARS-CoV-2-S antibodies listed in Table 2. In a related embodiment, said antibody, or antigen-binding fragment thereof, comprises a set of six CDRs (i.e. , HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3) contained within an HCVR/LCVR amino acid sequence pair as defined by any of the exemplary anti-SARS-CoV-2-S antibodies listed in Table 2. Methods and techniques for identifying CDRs within HCVR and LCVR amino acid sequences are well known in the art and can be used to identify CDRs within the specified HCVR and/or LCVR amino acid sequences disclosed herein. Exemplary conventions that can be used to identify the boundaries of CDRs include, e.g., the Kabat definition, the Chothia definition, and the AbM definition. In general terms, the Kabat definition is based on sequence variability, the Chothia definition is based on the location of the structural loop regions, and the AbM definition is a compromise between the Kabat and Chothia approaches. See, e.g., Kabat, "Sequences of Proteins of Immunological Interest," National Institutes of Health, Bethesda, Md. (1991 ) ; Al-Lazikani et al., J. Mol. Biol. 273:927-948 (1997) ; and Martin et al., Proc. Natl. Acad. Sci. USA 86:9268-9272 (1989). Public databases are also available for identifying CDR sequences within an antibody.

In preferred embodiments, said three heavy chain complementarity determining regions (CDRs) (HCDR1, HCDR2 and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) contained within said HCVR/LCVR amino acid sequence pairs listed in Table 2, have the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set of SEQ ID NOs: 2-3-4-6-7-8 (e.g. contained within the HCVR/LCVR amino acid sequence pair 1/5), 10-11-12-14-15-16 (e.g. contained within the HCVR/LCVR amino acid sequence pair 9/13), 18-19-20-22-23-24 (e.g. contained within the HCVR/LCVR amino acid sequence pair 17/21), 26-27-28-30-31-32 (e.g. contained within the HCVR/LCVR amino acid sequence pair 25/29), 34-35-36-38-39-40 (e.g. contained within the HCVR/LCVR amino acid sequence pair 33/37), 42-43-44-46-47-48 (e.g. contained within the HCVR/LCVR amino acid sequence pair 41/45), 50-51-52-54-55-56 (e.g. contained within the HCVR/LCVR amino acid sequence pair 49/53), 58-59-60-62-63-64 (e.g. contained within the HCVR/LCVR amino acid sequence pair 57/61), 66-67-68-70-71-72 (e.g. contained within the HCVR/LCVR amino acid sequence pair 65/69), 74-75-76-78-79-80 (e.g. contained within the HCVR/LCVR amino acid sequence pair 73/77), 82-83-84-86-87-88 (e.g. contained within the HCVR/LCVR amino acid sequence pair 81/85), 90-91-92-94-95-96 (e.g. contained within the HCVR/LCVR amino acid sequence pair 89/93), 98-99-100-102-103-104 (e.g. contained within the HCVR/LCVR amino acid sequence pair 97/101), 106-107-108-110-111-112 (e.g. contained within the HCVR/LCVR amino acid sequence pair 105/109), 114-115-116-118-119-120 (e.g. contained within the HCVR/LCVR amino acid sequence pair 113/117), 122-123-124-126- 127-128 (e.g. contained within the HCVR/LCVR amino acid sequence pair 121/125), 130- 131-132-134-135-136 (e.g. contained within the HCVR/LCVR amino acid sequence pair 129/133), 138-139-140-142-143-144 (e.g. contained within the HCVR/LCVR amino acid sequence pair 137/141), 146-147-148-150-151-152 (e.g. contained within the HCVR/LCVR amino acid sequence pair 145/149), 154-155-156-158-159-160 (e.g. contained within the HCVR/LCVR amino acid sequence pair 153/157), 162-163-164-166-167-168 (e.g. contained within the HCVR/LCVR amino acid sequence pair 161/165), 170-171-172-174-175-176 (e.g. contained within the HCVR/LCVR amino acid sequence pair 169/173), 178-179-180-182- 183-184 (e.g. contained within the HCVR/LCVR amino acid sequence pair 177/181), 186- 187-188-190-191-192 (e.g. contained within the HCVR/LCVR amino acid sequence pair 185/189), 194-195-196-198-199-200 (e.g. contained within the HCVR/LCVR amino acid sequence pair 193/197), 202-203-204-206-207-208 (e.g. contained within the HCVR/LCVR amino acid sequence pair 201/205), 214-215-216-210-211-212 (e.g. contained within the HCVR/LCVR amino acid sequence pair 213/209), 218-219-220-222-223-224 (e.g. contained within the HCVR/LCVR amino acid sequence pair 217/221), 226-227-228-230-231-232 (e.g. contained within the HCVR/LCVR amino acid sequence pair 225/229), 234-235-236-238- 239-240 (e.g. contained within the HCVR/LCVR amino acid sequence pair 233/237), 242- 243-244-246-247-248 (e.g. contained within the HCVR/LCVR amino acid sequence pair 241/245), 250-251-252-254-255-256 (e.g. contained within the HCVR/LCVR amino acid sequence pair 249/253), 258-259-260-262-263-264 (e.g. contained within the HCVR/LCVR amino acid sequence pair 257/261), 266-267-268-270-271-272 (e.g. contained within the HCVR/LCVR amino acid sequence pair 265/269), 274-275-276-278-279-280 (e.g. contained within the HCVR/LCVR amino acid sequence pair 273/277), 282-283-284-286-287-288 (e.g. contained within the HCVR/LCVR amino acid sequence pair 281/285), 290-291-292-294- 295-296 (e.g. contained within the HCVR/LCVR amino acid sequence pair 289/293), 298- 299-300-302-303-304 (e.g. contained within the HCVR/LCVR amino acid sequence pair 297/301), 306-307-308-310-311-312 (e.g. contained within the HCVR/LCVR amino acid sequence pair 305/309), 314-315-316-318-319-320 (e.g. contained within the HCVR/LCVR amino acid sequence pair 313/317), 322-323-324-326-327-328 (e.g. contained within the HCVR/LCVR amino acid sequence pair 321/325), 330-331-332-334-335-336 (e.g. contained within the HCVR/LCVR amino acid sequence pair 329/333), 338-339-340-342-343-344 (e.g. contained within the HCVR/LCVR amino acid sequence pair 337/341), 346-347-348-350- 351-352 (e.g. contained within the HCVR/LCVR amino acid sequence pair 345/349), 354- 355-356-358-359-360 (e.g. contained within the HCVR/LCVR amino acid sequence pair 353/357), 362-363-364-366-367-368 (e.g. contained within the HCVR/LCVR amino acid sequence pair 361/365), 370-371-372-374-375-376 (e.g. contained within the HCVR/LCVR amino acid sequence pair 369/373), 382-383-384-386-387-388 (e.g. contained within the HCVR/LCVR amino acid sequence pair 381/385), 390-391-392-394-395-396 (e.g. contained within the HCVR/LCVR amino acid sequence pair 389/393), 398-399-400-402-403-404 (e.g. contained within the HCVR/LCVR amino acid sequence pair 397/401), 406-407-408-410- 411-412 (e.g. contained within the HCVR/LCVR amino acid sequence pair 405/409), 414- 415-416-418-419-420 (e.g. contained within the HCVR/LCVR amino acid sequence pair 413/417), 422-423-424-426-427-428 (e.g. contained within the HCVR/LCVR amino acid sequence pair 421/425), 430-431-432-434-435-436 (e.g. contained within the HCVR/LCVR amino acid sequence pair 429/433), 438-439-440-442-443-444 (e.g. contained within the HCVR/LCVR amino acid sequence pair 437/441), 446-447-448-450-451-452 (e.g. contained within the HCVR/LCVR amino acid sequence pair 445/449), 454-455-456-458-459-460 (e.g. contained within the HCVR/LCVR amino acid sequence pair 453/457), 462-463-464-466- 467-468 (e.g. contained within the HCVR/LCVR amino acid sequence pair 461/465), 470- 471-472-474-475-476 (e.g. contained within the HCVR/LCVR amino acid sequence pair 469/473), 478-479-480-482-483-484 (e.g. contained within the HCVR/LCVR amino acid sequence pair 477/481), 486-487-488-490-491-492 (e.g. contained within the HCVR/LCVR amino acid sequence pair 485/489), 494-495-496-498-499-500 (e.g. contained within the HCVR/LCVR amino acid sequence pair 493/497), 502-503-504-506-507-508 (e.g. contained within the HCVR/LCVR amino acid sequence pair 501/505), 510-511-512-514-515-516 (e.g. contained within the HCVR/LCVR amino acid sequence pair 509/513), 518-519-520-522- 523-524 (e.g. contained within the HCVR/LCVR amino acid sequence pair 517/521), 526- 527-528-530-531-532 (e.g. contained within the HCVR/LCVR amino acid sequence pair 525/529), 534-535-536-538-539-540 (e.g. contained within the HCVR/LCVR amino acid sequence pair 533/537), 542-543-544-546-547-548 (e.g. contained within the HCVR/LCVR amino acid sequence pair 541/545), 550-551-552-554-555-556 (e.g. contained within the HCVR/LCVR amino acid sequence pair 549/553), 558-559-560-562-563-564 (e.g. contained within the HCVR/LCVR amino acid sequence pair 557/561), 566-567-568-570-571-572 (e.g. contained within the HCVR/LCVR amino acid sequence pair 565/569), 574-575-576-578- 579-580 (e.g. contained within the HCVR/LCVR amino acid sequence pair 573/577), 582- 583-584-586-587-588 (e.g. contained within the HCVR/LCVR amino acid sequence pair 581/585), 590-591-592-594-595-596 (e.g. contained within the HCVR/LCVR amino acid sequence pair 589/593), 598-599-600-602-603-604 (e.g. contained within the HCVR/LCVR amino acid sequence pair 597/601), 606-607-608-610-611-612 (e.g. contained within the HCVR/LCVR amino acid sequence pair 605/609), 614-615-616-618-619-620 (e.g. contained within the HCVR/LCVR amino acid sequence pair 613/617), 622-623-624-626-627-628 (e.g. contained within the HCVR/LCVR amino acid sequence pair 621/625), 630-631-632-634- 635-636 (e.g. contained within the HCVR/LCVR amino acid sequence pair 629/633), 638- 639-640-642-643-644 (e.g. contained within the HCVR/LCVR amino acid sequence pair 637/641), 646-647-648-650-651-652 (e.g. contained within the HCVR/LCVR amino acid sequence pair 645/649), 654-655-656-658-659-660 (e.g. contained within the HCVR/LCVR amino acid sequence pair 653/657) or 662-663-664-666-667-668 (e.g. contained within the HCVR/LCVR amino acid sequence pair 661/665).

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336, 138-139-140-142-143-144, 266-267-268-270-271-272, 518-519-520-522-523-524, 162- 163-164-166-167-168, 90-91-92-94-95-96, 122-123-124-126-127-128 and 242-243-244-246- 247-248. An advantage of these antibodies is that they neutralize live SARS-CoV-2.

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336, 138-139-140-142-143-144, 266-267-268-270-271-272, 518-519-520-522-523-524, 162- 163-164-166-167-168, 90-91-92-94-95-96 and 122-123-124-126-127-128. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.76 pg/mL.

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336, 138-139-140-142-143-144, 266-267-268-270-271-272, 518-519-520-522-523-524, 162- 163-164-166-167-168 and 90-91-92-94-95-96. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC₅o value equal to or lower than 0.25 pg/mL.

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336, 138-139-140-142-143-144, 266-267-268-270-271-272, 518-519-520-522-523-524 and 162-163-164-166-167-168. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.17 pg/mL.

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336, 138-139-140-142-143-144, 266-267-268-270-271-272 and 518-519-520-522-523-524. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC₅o value equal to or lower than 0.048 pg/mL.

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336, 138-139-140-142-143-144 and 266-267-268-270-271-272. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.04 pg/mL.

In a preferred embodiment, the HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3 amino acid sequence set is selected from the group consisting of SEQ ID NOs: 330-331-332-334-335- 336 and 138-139-140-142-143-144. An advantage of these antibodies is that they neutralize live SARS-CoV-2 in human cells with an IC50 value equal to or lower than 0.01 pg/mL.

In a preferred embodiment, said antibody according to the invention comprises a HCVR having the amino acid sequence of SEQ ID NO: 329 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity and a LCVR having the amino acid sequence of SEQ ID NO:333 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In a preferred embodiment, said antibody according to the invention comprises a HCVR having the amino acid sequence of SEQ ID NO: 137 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity and a LCVR having the amino acid sequence of SEQ ID NO:141 or a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

In certain embodiments, the antibody or antigen-binding fragment thereof according to the invention is bispecific, comprising a first binding specificity to a first epitope in the receptor binding domain of SARS-CoV-2 spike protein and a second binding specificity to a second epitope in the receptor binding domain of SARS-CoV-2 spike protein, wherein the first and second epitopes are distinct and non-overlapping. In a preferred embodiment, said antibody or antigen-binding fragment thereof comprises said HCVR/LCVR amino acid sequence pair is SEQ ID NOs: 17/21. In another preferred embodiment, said antibody or antigen-binding fragment thereof comprises the HCVR/LCVR amino acid sequence pair which is selected from SEQ ID NOs: 161/165, 169/173, 193/197, 501/505. In another preferred embodiment, said antibody or antigen-binding fragment thereof comprises the HCVR/LCVR amino acid sequence pair which is selected from SEQ ID NOs: 89/93, 121/125, 137/141, 225/229, 241/245, 249/253, 265/269, 297/301, 313/317, 329/333, 345/349, 369/373, 517/521. Bispecific antibodies based on combinations with the HCVR/LCVR amino acid sequence pair SEQ ID NO: 121/125 are particularly effective against mutant variants B.1.1.7, B.1.351 and P.1. In a preferred embodiment, the bispecific antibody comprises a combination of a first HCVR/LCVR amino acid sequence pair and a second HCVR/LCVR amino acid sequence pair, wherein said first and said second HCVR/LCVR amino acid sequence pair is selected from the following combinations of a first and second HCVR/LCVR amino acid sequence pair (SEQ ID No of the first HCVR/LCVR amino acid sequence pair + SEQ ID No of the second HCVR/LCVR amino acid sequence pair):

137/141 + 161/165; 137/141 + 169/173; 137/141+345/349; 265/269+161/165;

265/269+169/173; 265/269+345/349; 329/333+161/165; 329/333+169/173;

329/333+121/125, 137/141 + 121/125 and 329/333+345/349.

In a preferred embodiment, said antibody or antigen-binding fragment thereof according to the invention has a modified glycosylation pattern. In some embodiments, modification to remove undesirable glycosylation sites may be useful, or an antibody lacking a fucose moiety present on the oligosaccharide chain, for example, to increase antibody dependent cellular cytotoxicity (ADCC) function (see Shield et al. (2002) JBC 277:26733). In other applications, modification of galactosylation can be made in order to modify complement dependent cytotoxicity (CDC). In another embodiment, mutations are introduced in the constant region of an antibody to change the function (ADCC, CDC, ADCP). In another embodiment, mutations are introduced in the constant region of an antibody to enhance the half-life.

In some preferred embodiments said antibodies and antigen-binding fragments thereof compete for specific binding to SARS-CoV-2-S with an antibody or antigen-binding fragment thereof comprising the CDRs of a HCVR and the CDRs of a LCVR, wherein the HCVR and LCVR each has an amino acid sequence selected from the HCVR and LCVR sequences listed in Table 2.

In some preferred embodiments said antibody or antigen-binding fragment thereof cross- competes for binding to SARS-CoV-2-S with a reference antibody or antigen-binding fragment thereof comprising the CDRs of a HCVR and the CDRs of a LCVR, wherein the HCVR and LCVR each has an amino acid sequence selected from the HCVR and LCVR sequences listed in Table 2.

In some embodiments, the antibody or antigen binding fragment thereof may bind specifically to SARS-CoV-2-S in an agonist manner, i.e. , it may enhance or stimulate SARS-CoV-2- S binding and/or activity; in other embodiments, the antibody may bind specifically to SARS- CoV-2-S in an antagonist manner, i.e., it may block SARS-CoV-2-S from binding to its receptor (ACE2).

In a second aspect, the present invention provides a nucleic acid molecule encoding an anti- SARS-CoV-2-S antibody or fragment thereof according to the invention. For example, the present invention provides nucleic acid molecules encoding any of the HCVR amino acid sequences listed in Table 2 or encoding a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

The present invention also provides nucleic acid molecules encoding any of the LCVR amino acid sequences listed in Table 2 or encoding a substantially similar sequence thereof having at least 90%, at least 95%, at least 98% or at least 99% sequence identity.

The present invention also provides nucleic acid molecules encoding an HCVR, wherein the HCVR comprises a set of three CDRs (i.e. , HCDR1-HCDR2-HCDR3), wherein the HCDR1 - HCDR2-HCDR3 amino acid sequence set is as defined by any of the exemplary anti-SARS- CoV-2-S antibodies listed in Table 2.

The present invention also provides nucleic acid molecules encoding an LCVR, wherein the LCVR comprises a set of three CDRs (i.e., LCDR1-LCDR2-LCDR3), wherein the LCDR1 - LCDR2-LCDR3 amino acid sequence set is as defined by any of the exemplary anti-SARS- CoV-2-S antibodies listed in Table 2.

The present invention also provides nucleic acid molecules encoding both an HCVR and an LCVR, wherein the HCVR comprises an amino acid sequence of any of the HCVR amino acid sequences listed in Table 2, and wherein the LCVR comprises an amino acid sequence of any of the LCVR amino acid sequences listed in Table 2.

In certain embodiments according to this aspect of the invention, the nucleic acid molecule encodes an HCVR and LCVR, wherein the HCVR and LCVR are both derived from the same anti-SARS-CoV-2-S antibody listed in Table 2.

The present invention provides nucleic acid molecules encoding any of the heavy chain amino acid sequences listed in Table 2.

In a related aspect, the present invention provides recombinant expression vectors capable of expressing a polypeptide comprising a heavy or light chain variable region of an anti- SARS-CoV-2-S antibody. For example, the present invention includes recombinant expression vectors comprising any of the nucleic acid molecules mentioned above, i.e., nucleic acid molecules encoding any of the HCVR, LCVR, and/or CDR sequences as set forth in Table 2. Also included within the scope of the present invention are host cells into which such vectors have been introduced, as well as methods of producing the antibodies or portions thereof by culturing the host cells under conditions permitting production of the antibodies or antibody fragments, and recovering the antibodies and antibody fragments so produced. In a third aspect, the invention provides a pharmaceutical composition comprising a therapeutically effective amount of at least one recombinant monoclonal antibody or antigen binding fragment thereof according to the invention and a pharmaceutically acceptable carrier. In a related aspect, the invention features a composition which is a combination of an anti-SARS-CoV-2-S antibody and a second therapeutic agent. In one embodiment, the second therapeutic agent is any agent that is advantageously combined with an anti-SARS- CoV-2-S antibody. Exemplary agents that may be advantageously combined with an anti- SARS-CoV-2-S antibody include, without limitation, other agents that bind and/or inhibit SARS-CoV-2 activity (including other antibodies or antigen-binding fragments thereof, etc.) and/or agents which do not directly bind SARS-CoV-2-S but nonetheless inhibit viral activity including infectivity of host cells. In certain embodiments, the invention provides for a pharmaceutical composition comprising: (a) a first anti-SARS-CoV-2-S antibody or antigen binding fragment thereof; (b) a second anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof, wherein the first antibody binds to a first epitope on SARS-CoV-2 spike protein and the second antibody binds to a second epitope on SARS-CoV-2 spike protein wherein the first and second epitopes are distinct and non-overlapping; and (c) a pharmaceutically acceptable carrier or diluent. In certain embodiments, the invention provides for a pharmaceutical composition comprising: (a) a first anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof; (b) a second anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof, wherein the first antibody does not cross-compete with the second antibody for binding to SARS-CoV-2 spike protein; and (c) a pharmaceutically acceptable carrier or diluent. In a preferred embodiment, said first anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof comprises at least the HCVR/LCVR amino acid sequence pair having SEQ ID NOs: 17/21, 161/165, 169/173, 501/505, and said second anti- SARS-CoV-2-S antibody or antigen-binding fragment thereof comprises at least the HCVR/LCVR amino acid sequence pair SEQ ID NOs selected from: 161/165, 169/173, 193/197, 501/505. In another preferred embodiment said first anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof comprises at least the HCVR/LCVR amino acid sequence pair of SEQ ID NOs: 17/21 , 161/165, 169/173, 501/505 and said anti-SARS-CoV- 2-S antibody or antigen-binding fragment thereof comprises at least the HCVR/LCVR amino acid sequence pair selected from SEQ ID NOs: 89/93, 121/125, 137/141 , 225/229, 241/245, 249/253, 265/269, 297/301, 313/317, 329/333, 345/349, 369/373 and 517/521.

In another preferred embodiment said first anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof comprises at least the HCVR/LCVR amino acid sequence pair is SEQ ID NOs: 161/165, 169/173, 193/197, 501/505 and said anti-SARS-CoV-2-S antibody or antigen binding fragment thereof comprises at least the HCVR/LCVR amino acid sequence pair is SEQ ID NOs: 89/93, 121/125, 137/141, 225/229, 241/245, 249/253, 265/269, 297/301, 313/317, 329/333, 345/349, 369/373, 517/521.

In a fourth aspect, the invention provides therapeutic methods for treating a disease or disorder associated with SARS-CoV-2 such as viral infection in a subject using an anti- SARS-CoV-2-S antibody or antigen-binding portion of an antibody of the invention, wherein the therapeutic methods comprise administering a therapeutically effective amount of a pharmaceutical composition comprising an antibody or antigen-binding fragment of an antibody of the invention to the subject in need thereof. The disorder treated is any disease or condition which is improved, ameliorated, inhibited or prevented by inhibition of SARS- CoV-2 activity. In certain embodiments, the invention provides methods to prevent, treat or ameliorate at least one symptom of SARS-CoV-2 infection, the method comprising administering a therapeutically effective amount of an anti-SARS-CoV-2-S antibody or antigen-binding fragment thereof of the invention to a subject in need thereof. In some embodiments, the present invention provides methods to ameliorate or reduce the severity of at least one symptom or indication of COVID 19 infection in a subject by administering an anti-SARS-CoV-2-S antibody of the invention, wherein the at least one symptom or indication is selected from the group consisting of inflammation in the lung, alveolar damage, fever, cough, shortness of breath, diarrhea, organ failure, pneumonia, septic shock and loss of smell.

In certain embodiments, the invention provides methods to decrease viral load in a subject, the methods comprising administering to the subject an effective amount of an antibody or fragment thereof of the invention that binds SARS-CoV-2-S and blocks SARS-CoV-2-S binding to host cell receptor ACE2. In some embodiments, the antibody or antigen-binding fragment thereof may be administered prophylactically or therapeutically to a subject having or at risk of having SARS-CoV-2 infection. The subjects at risk include, but are not limited to, an immunocompromised person, an elderly adult (more than 65 years of age), children younger than 2 years of age, healthcare workers, adults or children in close contact with a person(s) with confirmed or suspected SARS-CoV-2 infection, and people with underlying medical conditions such as pulmonary infection, heart disease or diabetes. In certain embodiments, the antibody or antigen-binding fragment thereof the invention is administered in combination with a second therapeutic agent to the subject in need thereof. The second therapeutic agent may be selected from the group consisting of an anti-inflammatory drug (such as corticosteroids, and non-steroidal anti-inflammatory drugs), an anti-infective drug, a different antibody to SARS-CoV-2 spike protein, an anti-viral drug, a vaccine for SARS-CoV- 2, a dietary supplement such as anti-oxidants and any other drug or therapy known in the art. In certain embodiments, the second therapeutic agent may be an agent that helps to counteract or reduce any possible side effect(s) associated with an antibody or antigen binding fragment thereof of the invention, if such side effect(s) should occur. The antibody or fragment thereof may be administered subcutaneously, intravenously, intradermal, intraperitoneally, orally, intramuscularly, or intracranially. In one embodiment, the antibody may be administered as a single intravenous infusion for maximum concentration of the antibody in the serum of the subject. The antibody or fragment thereof may be administered at a dose of about 0.1 mg/kg of body weight to about 100 mg/kg of body weight of the subject. In certain embodiments, an antibody of the present invention may be administered at one or more doses comprising between 50mg to 600mg.

The present invention also includes use of an anti-SARS-CoV-2-S antibody or antigen binding fragment thereof of the invention in the manufacture of a medicament for the treatment of a disease or disorder that would benefit from the blockade of SARS-CoV-2 binding and/or activity., Other embodiments will become apparent from a review of the ensuing detailed description.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows the design of SARS-CoV-2 S protein and serology of COSCA1-3. Schematic of the wild-type SARS-CoV-2 S protein comprising the signal peptide, the S1 and S2 domains separated by a furin-cleavage site (RRAR; top). Schematic of the stabilized prefusion SARS- CoV-2 S ectodomain, where the furin cleavage site is replaced for a glycine linker (GGGG), two proline mutations are introduced (K986P and V987P) and a trimerization domain, preceded by a linker (GSGG) is attached (bottom).

DETAILED DESCRIPTION

Before the present methods are described, it is to be understood that this invention is not limited to particular methods, and experimental conditions described, as such methods and conditions may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims., Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference in their entirety. Definitions

The term "COVID-19", refers to the newly-emerged Corona Virus SARS-COV-2 which was isolated and described in [J Korean Med Sci. 2020 Feb 24; 35(7): e84.] and identified as the cause for the outbreak of severe acute respiratory disease. The complete genomes of 15 2019-nCoV sequences have been downloaded from GISAID, (https://www.gisaid.org/) and GenBank (htp://www.ncbi.nlm.nih.gov/genbank/).

The term "SARS-CoV-2-S", also called "S protein" refers to the spike protein of the SARS- CoV-2 coronavirus. The amino acid sequence of full-length SARS-CoV-2 spike protein is exemplified by the amino acid sequence of spike protein of SARS-CoV-2 (SEQ ID NO: 669). SARS-CoV-2 spike protein is a homotrimeric glycoprotein that is anchored in the viral membrane. Recent studies have shown that the S protein of SARS-Cov-2 bears considerable structural homology to SARS-CoV, with the S protein consisting of two subdomains: the S1 domain, which contains the N-terminal domain (NTD) and the receptor binding domain (RBD) (exemplary sequence SEQ ID NO: 682) for the host cell receptor angiotensin converting enzyme-2 (ACE-2) and the S2 domain, which contains the fusion peptide (12, 13). Upon host cell receptor binding, the S protein undergoes a conformational change from a prefusion to postfusion state enabling fusion of the viral and human cell membrane (14, 15). When expressed as recombinant soluble proteins, class-1 fusion proteins generally have the propensity to switch to a postfusion state.

The term "SARS-CoV-2-S" also includes protein variants of SARS-CoV-2 spike protein isolated from different SARS-CoV-2 isolates, available on e.g. Nextstrain.org. The term "SARS-CoV-2-S" includes recombinant SARS-CoV-2 spike protein or a fragment thereof. The term also encompasses SARS-CoV-2 spike protein or a fragment thereof coupled to, for example, histidine tag, mouse or human Fc, or a signal sequence such as ROR1 . The term also includes protein variants that comprise a histidine, Strepll, Avidin, or I53-50A tag at the C- or N-terminal.

The term "SARS-CoV-2 infection", as used herein, refers to the severe acute respiratory illness caused by COVID 19 coronavirus and first reported in Wuhan, China in 2019. The term includes respiratory tract infection, often in the lower respiratory tract. The symptoms include high fever, cough, shortness of breath pneumonia, gastro-intestinal symptoms such as diarrhea, organ failure (kidney failure and renal dysfunction), septic shock, loss of smell and taste and death in severe cases.

The term "antibody", as used herein, is intended to refer to immunoglobulin molecules comprised of four polypeptide chains, two heavy (H) chains and two light (L) chains interconnected by disulfide bonds (i.e., "full antibody molecules"), as well as multimers thereof (e.g. IgM) or antigen-binding fragments thereof. Each heavy chain is comprised of a heavy chain variable region ("HCVR" or "VH ") and a heavy chain constant region (comprised of domains CH1 , CH2 and CH3). Each light chain is comprised of a light chain variable region ("LCVR or "VL ") and a light chain constant region (CL ). The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. In certain embodiments of the invention, the FRs of the antibody (or antigen binding fragment thereof) may be identical to the human germline sequences, or may be naturally or artificially modified. An amino acid consensus sequence may be defined based on a side-by-side analysis of two or more CDRs.

In a preferred embodiment, said HC comprises a VH1-69 or VH3-33.

The fully human anti-SARS-CoV-2-S monoclonal antibodies disclosed herein may comprise one or more amino acid substitutions, insertions and/or deletions in the framework and/or CDR regions of the heavy and light chain variable domains as compared to the corresponding germline sequences. Such mutations can be readily ascertained by comparing the amino acid sequences disclosed herein to germline sequences available from, for example, public antibody sequence databases. The present invention includes antibodies, and antigen-binding fragments thereof, which are derived from any of the amino acid sequences disclosed herein, wherein one or more amino acids within one or more framework and/or CDR regions are mutated to the corresponding residue(s) of the germline sequence from which the antibody was derived, or to the corresponding residue(s) of another human germline sequence, or to a conservative amino acid substitution of the corresponding germline residue(s) (such sequence changes are referred to herein collectively as "germline mutations"). A person of ordinary skill in the art, starting with the heavy and light chain variable region sequences disclosed herein, can easily produce numerous antibodies and antigen-binding fragments which comprise one or more individual germline mutations or combinations thereof. In certain embodiments, all of the framework and/or CDR residues within the VH and/or VL domains are mutated back to the residues found in the original germline sequence from which the antibody was derived. In other embodiments, only certain residues are mutated back to the original germline sequence, e.g., only the mutated residues found within the first 8 amino acids of FR1 or within the last 8 amino acids of FR4, or only the mutated residues found within CDR1, CDR2 or CDR3. In other embodiments, one or more of the framework and/or CDR residue(s) are mutated to the corresponding residue(s) of a different germline sequence (i.e., a germline sequence that is different from the germline sequence from which the antibody was originally derived). Furthermore, the antibodies of the present invention may contain any combination of two or more germline mutations within the framework and/or CDR regions, e.g., wherein certain individual residues are mutated to the corresponding residue of a particular germline sequence while certain other residues that differ from the original germline sequence are maintained or are mutated to the corresponding residue of a different germline sequence. Once obtained, antibodies and antigen-binding fragments that contain one or more germline mutations can be easily tested for one or more desired property such as, improved binding specificity, increased binding affinity, improved or enhanced antagonistic or agonistic biological properties (as the case may be), reduced immunogenicity, etc. Antibodies and antigen-binding fragments obtained in this general manner are encompassed within the present invention.

The present invention also includes fully human anti-SARS-CoV-2-S monoclonal antibodies comprising variants of any of the HCVR, LCVR, and/or CDR amino acid sequences disclosed herein having one or more conservative substitutions. For example, the present invention includes anti-SARS-CoV-2 antibodies having HCVR, LCVR, and/or CDR amino acid sequences with, e.g., 10 or fewer, 8 or fewer, 6 or fewer, 4 or fewer, etc. conservative amino acid substitutions relative to any of the HCVR, LCVR, and/or CDR amino acid sequences disclosed herein.

The term "human antibody", as used herein, is intended to include antibodies having variable and constant regions derived from human germline immunoglobulin sequences. The human mAbs of the invention may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo), for example in the CDRs and in particular CDR3.

However, the term "human antibody", as used herein, is not intended to include mAbs in which CDR sequences derived from the germline of another mammalian species (e.g., mouse), have been grafted onto human FR sequences. The term includes antibodies recombinantly produced in a non-human mammal, or in cells of a non-human mammal. In an embodiment, an antibody isolated from or generated in a human subject is excluded.

The term "recombinant", as used herein, refers to antibodies or antigen-binding fragments thereof of the invention created, expressed, isolated or obtained by technologies or methods known in the art as recombinant DNA technology which include, e.g., DNA splicing and transgenic expression. The term refers to antibodies expressed in a non-human mammal (including transgenic non-human mammals, e.g., transgenic mice), or a cell (e.g., CHO or HEK 293F cells) expression system or isolated from a recombinant combinatorial human antibody library.

The term "specifically binds," or "binds specifically to", or the like, means that an antibody or antigen-binding fragment thereof forms a complex with an antigen that is relatively stable under physiologic conditions. Specific binding can be characterized by an equilibrium dissociation constant of at least about 1 x10⁸ M or less (e.g., a smaller KD denotes a tighter binding). Methods for determining whether two molecules specifically bind are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance, and the like. As described herein, antibodies have been identified by surface plasmon resonance, e.g., BIACORE™, which bind specifically to SARS-CoV-2-S. Moreover, multi-specific antibodies that bind to one domain in SARS-CoV-2-S and one or more additional antigens or a bi-specific that binds to two different regions of SARS-CoV-2-S are nonetheless considered antibodies that "specifically bind", as used herein.

The term "high affinity" antibody refers to those mAbs having a binding affinity to SARS-CoV- 2-S, expressed as KD , of at least 10⁸ M; preferably 10⁹ M; more preferably 10¹° M, even more preferably 10¹¹ M, even more preferably 10¹² M, as measured by surface plasmon resonance, e.g., BIACORE™ or solution-affinity ELISA., By the term "slow off rate", "Koff" or "kd" is meant an antibody that dissociates from SARS-CoV-2, with a rate constant of 1 x 10³ s ¹ or less, preferably 1 x 10⁴ s^_1 or less, as determined by surface plasmon resonance, e.g., BIACORE™.

The terms "antigen-binding portion" of an antibody, "antigen-binding fragment" of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex. The terms "antigen-binding fragment" of an antibody, or "antibody fragment", as used herein, refers to one or more fragments of an antibody that retain the ability to bind to SARS-CoV-2 spike protein.

In specific embodiments, antibody or antibody fragments of the invention may be conjugated to a moiety such a ligand or a therapeutic moiety ("immunoconjugate"), such as an anti-viral drug, a second anti-SARS-CoV-2-S antibody, or any other therapeutic moiety useful for treating an infection caused by SARS-CoV-2.

An "isolated antibody", as used herein, is intended to refer to an antibody that is substantially free of other antibodies (Abs) having different antigenic specificities (e.g., an isolated antibody that specifically binds SARS-CoV-2-S, or a fragment thereof, is substantially free of Abs that specifically bind antigens other than SARS-CoV-2-S. A "blocking antibody" or a "neutralizing antibody", as used herein (or an "antibody that neutralizes SARS-CoV-2-S activity" or "antagonist antibody"), is intended to refer to an antibody whose binding to SARS-CoV-2-S results in inhibition of at least one biological activity of SARS-CoV-2. For example, an antibody of the invention may prevent or block SARS-CoV-2 binding to ACE2.

The term "surface plasmon resonance", as used herein, refers to an optical phenomenon that allows for the analysis of real-time biomolecular interactions by detection of alterations in protein concentrations within a biosensor matrix, for example using the BIACORE™ system (Pharmacia Biosensor AB, Uppsala, Sweden and Piscataway, N.J.).

The term “biolayer inferometry”, as used herein, refers to a technology for measuring biomolecular interactions. It is an optical analytical technique that analyzes the interference pattern of white light reflected from two surfaces: a layer of immobilized protein on the biosensor tip, and an internal reference layer.

The term "KD", as used herein, is intended to refer to the equilibrium dissociation constant of a particular antibody-antigen interaction.

The term "epitope" refers to an antigenic determinant that interacts with a specific antigen binding site in the variable region of an antibody molecule known as a paratope. A single antigen may have more than one epitope. Thus, different antibodies may bind to different areas on an antigen and may have different biological effects. The term "epitope" also refers to a site on an antigen to which B and/or T cells respond. It also refers to a region of an antigen that is bound by an antibody. Epitopes may be defined as structural or functional. Functional epitopes are generally a subset of the structural epitopes and have those residues that directly contribute to the affinity of the interaction. Epitopes may also be conformational, that is, composed of nonlinear amino acids. In certain embodiments, epitopes may include determinants that are chemically active surface groupings of molecules such as amino acids, sugar side chains, phosphoryl groups, or sulfonyl groups, and, in certain embodiments, may have specific three- dimensional structural characteristics, and/or specific charge characteristics.

The term "cross-corn petes", as used herein, means an antibody or antigen-binding fragment thereof binds to an antigen and inhibits or blocks the binding of another antibody or antigen binding fragment thereof. The term also includes competition between two antibodies in both orientations, i.e. , a first antibody that binds and blocks binding of second antibody and vice- versa. In certain embodiments, the first antibody and second antibody may bind to the same epitope. Alternatively, the first and second antibodies may bind to different, but overlapping epitopes such that binding of one inhibits or blocks the binding of the second antibody, e.g., via steric hindrance. Cross-competition between antibodies may be measured by methods known in the art, for example, by a real-time, label-free bio-layer interferometry assay. Cross competition between two antibodies may be expressed as the binding of the second antibody that is less than the background signal due to self-self binding (wherein first and second antibodies is the same antibody). Cross-competition between 2 antibodies may be expressed, for example, as % binding of the second antibody that is less than the baseline self-self background binding (wherein first and second antibodies is the same antibody).

The term "substantial identity" or "substantially identical," when referring to a nucleic acid or fragment thereof, indicates that, when optimally aligned with appropriate nucleotide insertions or deletions with another nucleic acid (or its complementary strand), there is nucleotide sequence identity in at least about 90%, and more preferably at least about 95%, 96%, 97%, 98% or 99% of the nucleotide bases, as measured by any well-known algorithm of sequence identity, such as FASTA, BLAST or GAP, as discussed below. A nucleic acid molecule having substantial identity to a reference nucleic acid molecule may, in certain instances, encode a polypeptide having the same or substantially similar amino acid sequence as the polypeptide encoded by the reference nucleic acid molecule. As applied to polypeptides, the term "substantial similarity" or "substantially similar" means that two peptide sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default gap weights, share at least 90% sequence identity, even more preferably at least 95%, 98% or 99% sequence identity. Preferably, residue positions, which are not identical, differ by conservative amino acid substitutions. A "conservative amino acid substitution" is one in which an amino acid residue is substituted by another amino acid residue having a side chain (R group) with similar chemical properties (e.g., charge or hydrophobicity). In general, a conservative amino acid substitution will not substantially change the functional properties of a protein. In cases where two or more amino acid sequences differ from each other by conservative substitutions, the percent or degree of similarity may be adjusted upwards to correct for the conservative nature of the substitution. Means for making this adjustment are well known to those of skill in the art. See, e.g., Pearson (1994) Methods Mol. Biol. 24: 307- 331. Examples of groups of amino acids that have side chains with similar chemical properties include 1 ) aliphatic side chains: glycine, alanine, valine, leucine and isoleucine; 2) aliphatic-hydroxyl side chains: serine and threonine; 3) amide- containing side chains: asparagine and glutamine; 4) aromatic side chains: phenylalanine, tyrosine, and tryptophan; 5) basic side chains: lysine, arginine, and histidine; 6) acidic side chains: aspartate and glutamate, and 7) sulfur-containing side chains: cysteine and methionine. Preferred conservative amino acids substitution groups are: valine-leucine-isoleucine, phenylalanine- tyrosine, lysine-arginine, alanine-valine, glutamate-aspartate, and asparagine- glutamine. Alternatively, a conservative replacement is any change having a positive value in the PAM250 log-likelihood matrix disclosed in Gonnet et al. (1992) Science 256: 144345, herein incorporated by reference. A "moderately conservative" replacement is any change having a nonnegative value in the PAM250 log-likelihood matrix., Sequence similarity for polypeptides is typically measured using sequence analysis software. Protein analysis software matches similar sequences using measures of similarity assigned to various substitutions, deletions and other modifications, including conservative amino acid substitutions. For instance, GCG software contains programs such as GAP and BESTFIT which can be used with default parameters to determine sequence homology or sequence identity between closely related polypeptides, such as homologous polypeptides from different species of organisms or between a wild type protein and a mutein thereof. See, e.g., GCG Version 6.1 . Polypeptide sequences also can be compared using FASTA with default or recommended parameters; a program in GCG Version 6.1. FASTA (e.g., FASTA2 and FASTA3) provides alignments and percent sequence identity of the regions of the best overlap between the query and search sequences (Pearson (2000) supra). Another preferred algorithm when comparing a sequence of the invention to a database containing a large number of sequences from different organisms is the computer program BLAST, especially BLASTP or TBLASTN, using default parameters. See, e.g., Altschul et al. (1990) J. Mol. Biol. 215: 403-410 and (1997) Nucleic Acids Res. 25:3389-3402.

By the phrase "therapeutically effective amount" is meant an amount that produces the desired effect for which it is administered. The exact amount will depend on the purpose of the treatment, and will be ascertainable by one skilled in the art using known techniques (see, for example, Lloyd (1999) The Art, Science and Technology of Pharmaceutical Compounding).

As used herein, the term "subject" refers to an animal, preferably a mammal, more preferably a human, in need of amelioration, prevention and/or treatment of a disease or disorder such as viral infection. The term includes human subjects who have or are at risk of having COVID 19 infection.

As used herein, the terms "treat", "treating", or "treatment" refer to the reduction or amelioration of the severity of at least one symptom or indication of COVID 19 infection due to the administration of a therapeutic agent such as an antibody of the present invention to a subject in need thereof. The terms include inhibition of progression of disease or of worsening of infection. The terms also include positive prognosis of disease, i.e. , the subject may be free of infection or may have reduced or no viral titers upon administration of a therapeutic agent such as an antibody of the present invention. The therapeutic agent may be administered at a therapeutic dose to the subject., The terms "prevent", "preventing" or "prevention" refer to inhibition of manifestation of COVID 19 infection or any symptoms or indications of COVID 19 infection upon administration of an antibody of the present invention. The term includes prevention of spread of infection in a subject exposed to the virus or at risk of having COVID 19 infection.

As used herein, the term "anti-viral drug" refers to any anti-infective drug or therapy used to treat, prevent, or ameliorate a viral infection in a subject. The term "anti-viral drug" includes, but is not limited to ribavirin, oseltamivir, zanamivir, interferon-alpha2b, analgesics and corticosteroids. In the context of the present invention, the viral infections include infection caused by human coronaviruses, including but not limited to, SARS-CoV-2, HCoV_229E, HCoV_NL63, HCoV-OC43, HCoV_HKU1, and SARS-CoV.

General Description

The inventors have described herein fully human antibodies and antigen-binding fragments thereof that specifically bind to SARS-CoV-2-S. Many of the antibodies described herein were capable of neutralizing SARS-CoV-2 in pseudovirus and live virus assays as described herein. Many were capable of modulating the interaction of SARS-CoV-2-S with ACE2.

19 mAbs disclosed herein inhibited SARS-CoV-2 pseudovirus infection with varying potencies of which 14 (74%) bind the RBD, and at least one (COVA1-22) bids to NTD Nine mAbs could be categorized as potent neutralizers (IC50 < 0.1 pg/mL), three as moderate (IC50 of 0.1-1 pg/mL) and seven as weak neutralizers (IC50 of 1-10 pg/mL). With IC50s of 0.008 pg/mL the RBD-targeting antibodies COVA1-18 and COVA2-15, in particular, were remarkably potent.

Furthermore, two of the 17 mAbs that also interacted with the SARS-CoV S and RBD proteins cross-neutralized the SARS-CoV pseudovirus (IC50 of 2.5 pg/mL for COVA1-16 and 0.61 pg/mL for COVA2-02; Table 5), with COVA2-02 being more potent against SARS-CoV than against SARS-CoV-2.

The inventors also assessed the ability of the 19 mAbs to block infection of live SARS-CoV-2 virus. They observed very similar potencies for the most potent mAbs (IC50S of 0.007 and 0.010 pg/mL for COVA2-15 and COVA1-18, respectively, Table 5), making them the most potent mAbs against SARS-CoV-2 described to date. NAbs COVA1-18, COVA2-07, COVA2- 15, COVA2-29 and COVA2-39 also showed strong competition with ACE2 binding, further supporting that blocking ACE2 binding is their mechanism of neutralization (Table 7). RBD- targeting mAb COVA2-17 however did not show any competition with ACE2. This corroborates previous observations that the RBD encompasses multiple distinct antigenic sites of which some do not block ACE2 binding (23).

The antibody and fragment thereof according to the invention preferably binds to SARS-CoV- 2-S with high affinity. In a preferred embodiment, the antibody and fragment thereof according to the invention binds to SARS-CoV-2-S and blocks the interaction of SARS-CoV- 2-S with ACE2. In a preferred embodiment, the antibody and fragment thereof according to the invention blocks the binding of SARS-CoV-2-S to ACE2 and/or inhibits or neutralizes viral infectivity of host cells. In some embodiments, the blocking antibodies may be useful for treating a subject suffering from COVID 19 infection. In certain preferred embodiments, selected antibodies according to the invention that do not cross-compete for binding to the spike protein are used in combination as a cocktail to reduce the ability of the virus to escape via mutation in response to the selective pressure from either component. The antibodies when administered to a subject in need thereof may reduce the infection by a virus such as SARS-CoV-2 in the subject. They may be used to decrease viral loads in a subject. They may be used alone or as adjunct therapy with other therapeutic moieties or modalities known in the art for treating viral infection.

The antibodies of the present invention may be produced by immunizing an animal with a SARS-CoV-2-S immunogen. The antibodies of the invention may be obtained from animals immunized with a primary immunogen, such as a full length SARS-CoV-2 spike protein (SEQ ID NO: 669) which includes the native signal peptide (residues 1-14; SEQ ID NO: 673), or with a recombinant soluble form of SARS-CoV-2-S or modified SARS-CoV-2-S fragments (such as residues 15-1273 of SEQ ID NO: 669, SEQ ID NO: 670, SEQ ID NO:675 or SEQ ID NO: 681). The native signal peptide (residues 1-14; SEQ ID NO: 673) may suitably be replaced a non-native signal peptide such as the tissue plasminogen activator signal peptide (SEQ ID NO: 680). In some embodiments, said step of primary immunization is followed by immunization with a secondary immunogen, or with an immunogenically active fragment of SARS-CoV-2-S. The immunogen may be a biologically active and/or immunogenic fragment of SARS-CoV-2-S or DNA encoding the active fragment thereof. The fragment may be derived from the N- terminal or C-terminal domain of SARS-CoV-2-S. In certain embodiments of the invention, the immunogen is a fragment of SARS-CoV-2-S that ranges from amino acid residues 319-529 of SEQ ID NO: 674. In a preferred embodiment, said SARS-CoV-2 spike protein is a stabilized prefusion S-protein (SEQ ID NO: 670), preferably using stabilization strategies as previously described for S proteins of SARS-CoV-2 and other b-coronaviruses, preferably lacking the amino acid residues of the transmembrane domain (residues 1214-1234) and cytoplasmic tail (1235-1273), preferably being genetically linked to a trimerization domain such as the Foldon trimerization domain (SEQ ID NO: 678) or an isoluecin zipper (see Fig. 1) (12, 31).

The peptides may be modified to include addition or substitution of certain residues for tagging or for purposes of conjugation to carrier molecules, such as, KLH. For example, a cysteine may be added at either the N terminal or C terminal end of a peptide, or a linker sequence may be added to prepare the peptide for conjugation to, for example, KLH for immunization.

Certain anti-SARS-CoV-2-S antibodies of the present invention are able to bind to and neutralize the activity of SARS-CoV-2-S, as determined by in vitro or in vivo assays. The ability of the antibodies of the invention to bind to and neutralize the activity of SARS-CoV-2- S may be measured using any standard method known to those skilled in the art, including binding assays, or activity assays, as described herein.

Non-limiting, exemplary in vitro assays for measuring binding and blocking activity are illustrated in Examples 4 - 5, herein. In Example 4, the binding affinity and dissociation constants of anti-SARS-CoV-2-S antibodies for SARS-CoV-2-S were determined by surface plasmon resonance assay. In Example 5, neutralization assays were used to determine infectivity of SARS-CoV-2 spike protein-containing virus-like particles. In Example 5, neutralization assays were used to determine infectivity of SARS-CoV-2 spike protein- containing in live SARS-CoV-2 virus. The antibodies specific for SARS-CoV-2-S may contain no additional labels or moieties, or they may contain an N-terminal or C-terminal label or moiety. In one embodiment, the label or moiety is biotin. In a binding assay, the location of a label (if any) may determine the orientation of the peptide relative to the surface upon which the peptide is bound. For example, if a surface is coated with avidin, a peptide containing an N-terminal biotin will be oriented such that the C- terminal portion of the peptide will be distal to the surface. In one embodiment, the label may be a radionuclide, a fluorescent dye or a MRI-detectable label. In certain embodiments, such labeled antibodies may be used in diagnostic assays including imaging assays.

Antigen-Binding Fragments of Antibodies

Unless specifically indicated otherwise, the term "antibody," as used herein, shall be understood to encompass antibody molecules comprising two immunoglobulin heavy chains and two immunoglobulin light chains {i.e. , "full antibody molecules") as well as antigen binding fragments thereof.

The terms "antigen-binding portion" of an antibody, "antigen-binding fragment" of an antibody, and the like, as used herein, include any naturally occurring, enzymatically obtainable, synthetic, or genetically engineered polypeptide or glycoprotein that specifically binds an antigen to form a complex.

The terms "antigen-binding fragment" of an antibody, or "antibody fragment", as used herein, refers to one or more fragments of an antibody that retain the ability to specifically bind to SARS-CoV-2 spike protein. An antibody fragment may include a Fab fragment, a F(ab')2 fragment, a Fv fragment, a dAb fragment, a fragment containing a CDR, or an isolated CDR. In a preferred embodiment it contains 3 CDRs (HCDR1 , HCDR2 and HCDR3 or (LCDR1 , LCDR2 and LCDR3). In certain embodiments, the term "antigen-binding fragment" refers to a polypeptide fragment of a multi-specific antigen-binding molecule. Antigen-binding fragments of an antibody may be derived, e.g., from full antibody molecules using any suitable standard techniques such as proteolytic digestion or recombinant genetic engineering techniques involving the manipulation and expression of DNA encoding antibody variable and (optionally) constant domains. Such DNA is known and/or is readily available from, e.g., commercial sources, DNA libraries (including, e.g., phage-antibody libraries), or can be synthesized. The DNA may be sequenced and manipulated chemically or by using molecular biology techniques, for example, to arrange one or more variable and/or constant domains into a suitable configuration, or to introduce codons, create cysteine residues, modify, add or delete amino acids, etc., Non-limiting examples of antigen-binding fragments include: (i) Fab fragments; (ii) F(ab')2 fragments; (iii) Fd fragments; (iv) Fv fragments; (v) single-chain Fv (scFv) molecules; (vi) dAb fragments; and (vii) minimal recognition units consisting of the amino acid residues that mimic the hypervariable region of an antibody {e.g., an isolated complementarity determining region (CDR) such as a CDR3 peptide), or a constrained FR3-CDR3-FR4 peptide. Other engineered molecules, such as domain-specific antibodies, single domain antibodies, domain- deleted antibodies, chimeric antibodies, CDR-grafted antibodies, diabodies, triabodies, tetrabodies, minibodies, nanobodies {e.g. monovalent nanobodies, bivalent nanobodies, etc.), small modular immunopharmaceuticals (SMIPs), and shark variable IgNAR domains, are also encompassed within the expression "antigen-binding fragment," as used herein.

An antigen-binding fragment of an antibody will typically comprise at least one variable domain. The variable domain may be of any size or amino acid composition and will generally comprise at least one CDR, which is adjacent to or in frame with one or more framework sequences. In antigen-binding fragments having a VH domain associated with a VL domain, the VH and VL domains may be situated relative to one another in any suitable arrangement. For example, the variable region may be dimeric and contain VH - VH , VH - VL or VL - VL dimers. Alternatively, the antigen-binding fragment of an antibody may contain a monomeric VH or VL domain.

In certain embodiments, an antigen-binding fragment of an antibody may contain at least one variable domain covalently linked to at least one constant domain.

As with full antibody molecules, antigen-binding fragments may be mono-specific or multi specific (e.g., bi-specific, tri-specific). A multi-specific antigen-binding fragment of an antibody will typically comprise at least two different variable domains, wherein each variable domain is capable of specifically binding to a separate antigen or to a different epitope on the same antigen. Any multi-specific antibody format, including the exemplary bi-specific antibody formats disclosed herein, may be adapted for use in the context of an antigen-binding fragment of an antibody of the present invention using routine techniques available in the art.

Preparation of Human Antibodies

Methods for generating human antibodies in transgenic mice are known in the art. Any such known methods can be used in the context of the present invention to make human antibodies that specifically bind to SARS-CoV-2 spike protein.

An immunogen comprising any one of the following can be used to generate antibodies to SARS-CoV-2 spike protein. In certain embodiments, the antibodies of the invention are obtained from mice immunized with a full length, native SARS-CoV-2 spike protein, or an immunogenically active fragment of SARS-CoV-2-S (including but not limited to a a recombinant ectodomain of SARS-CoV-2-S), or with DNA encoding the protein or fragment thereof. Alternatively, the spike protein or a fragment thereof may be produced using standard biochemical techniques and modified and used as immunogen. In one embodiment, the immunogen is the receptor binding domain (S1) of SARS-CoV-2 spike protein. In certain embodiments of the invention, the immunogen is the Receptor Binding Domain (RBD, that ranges from about amino acid residues 319 - 529 of SEQ ID NO: 669. In a preferred embodiment, said immunogen is complete prefusion S protein ectodomain of SARS-CoV-2 (residues 1-1138 of SEQ ID NO: 669).

In some embodiments, the immunogen may be a recombinant SARS-CoV-2 spike protein receptor binding domain peptide expressed in E. Coli or in any other eukaryotic or mammalian cells such as Chinese hamster ovary (CHO) cells or HEK273 cells.

Bioequivalents

The anti-SARS-CoV-2-S antibodies and antibody fragments of the present invention encompass proteins having amino acid sequences that vary from those of the described antibodies, but that retain the ability to bind SARS-CoV-2 spike protein. Such variant antibodies and antibody fragments comprise one or more additions, deletions, or substitutions of amino acids when compared to parent sequence, but exhibit biological activity that is essentially equivalent to that of the described antibodies. Likewise, the antibody-encoding DNA sequences of the present invention encompass sequences that comprise one or more additions, deletions, or substitutions of nucleotides when compared to the disclosed sequence, but that encode an antibody or antibody fragment that is essentially bioequivalent to an antibody or antibody fragment of the invention.

Bioequivalent variants of the antibodies of the invention may be constructed by, for example, making various substitutions of residues or sequences or deleting terminal or internal residues or sequences not needed for biological activity. For example, cysteine residues not essential for biological activity can be deleted or replaced with other amino acids to prevent formation of unnecessary or incorrect intramolecular disulfide bridges upon renaturation. In other contexts, bioequivalent antibodies may include antibody variants comprising amino acid changes, which modify the glycosylation characteristics of the antibodies, e.g., mutations that eliminate or remove glycosylation.

Biological Characteristics of the Antibodies In general, the antibodies of the present invention function by binding to SARS-CoV-2 spike protein. In certain embodiments, the antibodies of the present invention bind with high affinity to the spike protein of SARS-CoV-2. For example, the present invention includes antibodies and antigen-binding fragments of antibodies that bind SARS-CoV-2 spike protein with a KD of less than 20nM as measured by surface plasmon resonance, e.g., using the assay format as defined in Example 4 herein. In preferred embodiments, the antibodies or antigen-binding fragments thereof bind dimeric SARS-CoV-2-S with a KD of less than about 175, 155, 125,

100, 90, 80, 70, 60, 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4.5, 4,0, 3,8, 3,3, 1,9, 1,4, 1.0, 0,75, 0.5,

0.4, 0.3, 0.2, 0.1, 0.08, 0.06, 0.04, 0.03, 0.025, 0.02 or 0.01 nM as measured by surface plasmon resonance, e.g., using the assay format as defined in Example 4 herein, or a substantially similar assay.

In some preferred embodiments, said antibody according to the invention binds with high affinity to the stabilized prefusion SARS-CoV-2 spike protein as disclosed herein.

The present invention also includes antibodies or antigen-binding fragments thereof that block more than 40%40%, more preferably 50%, 60%, 70%, 80%, 90% or 100% of SARS- CoV-2-S binding to ACE2 as can be determined using a bio-layer interferometry assay (e.g. Octet), as shown in Example 2, or a substantially similar assay.

In some embodiments, the antibodies of the present invention bind to the receptor binding domain of SARS-CoV-2 spike protein or to a fragment of the domain. In some embodiments, the antibodies of the present invention may bind to more than one domain (cross- reactive antibodies). In certain embodiments, the antibodies of the present invention may bind to an epitope located in the receptor binding domain comprising amino acid residues 319 - 529 of SARS-CoV-2-S. In one embodiment, the antibodies may bind to an epitope comprising one or more amino acids selected from the group consisting of amino acid residues 319 - 529 of the sequence set forth in SEQ ID NO: 669

In certain embodiments, the antibodies of the present invention may function by blocking or inhibiting the ACE2-binding activity associated with SARS-CoV-2 spike protein by binding to any other region or fragment of the full length protein, the amino acid sequence of which is set forth in SEQ ID NO: 669.

In certain embodiments, the antibodies of the present invention may be bi-specific antibodies. The bi-specific antibodies of the invention may bind one epitope in one domain and may also bind a second epitope in the same or a different domain of SARS-CoV-2 spike protein. In certain embodiments, the bi-specific antibodies of the invention may bind two different epitopes in the same domain. The antibodies of the present invention may possess one or more of the aforementioned biological characteristics, or any combinations thereof. Other biological characteristics of the antibodies of the present invention will be evident to a person of ordinary skill in the art from a review of the present disclosure including the working Examples herein.

Epitope Mapping and Related Technologies

The present invention includes anti-SARS-CoV-2-S antibodies which interact with one or more amino acids found within one or more domains of the SARS-CoV-2 spike protein molecule including, the N-terminal S1 domain and C-terminal S2 domain (see Fig. 1). The epitope to which the antibodies bind may consist of a single contiguous sequence of 3 or more (e.g., 3, 4, 5, 6, 7, 8, 9, 10, 1 1 , 12, 13, 14, 15, 16, 17, 18, 19, 20 or more) amino acids located within any of the aforementioned domains of the SARS-CoV-2 spike protein molecule (e.g. a linear epitope in a domain). Alternatively, the epitope may consist of a plurality of non contiguous amino acids (or amino acid sequences) located within either or both of the aforementioned domains of the spike protein molecule (e.g. a conformational epitope).

Various techniques known to persons of ordinary skill in the art can be used to determine whether an antibody "interacts with one or more amino acids" within a polypeptide or protein. Exemplary techniques include, for example, routine cross-blocking assays, such as that described in Antibodies, Harlow and Lane (Cold Spring Harbor Press, Cold Spring Harbor, NY). Other methods include alanine scanning mutational analysis, peptide blot analysis (Reineke (2004) Methods Mol. Biol. 248: 443-63), peptide cleavage analysis crystallographic studies and NMR analysis. In addition, methods such as epitope excision, epitope extraction and chemical modification of antigens can be employed (Tomer (2000) Prot. Sci. 9: 487- 496). Another method that can be used to identify the amino acids within a polypeptide with which an antibody interacts is hydrogen/deuterium exchange detected by mass spectrometry. In general terms, the hydrogen/deuterium exchange method involves deuterium-labeling the protein of interest, followed by binding the antibody to the deuterium- labeled protein. Next, the protein/antibody complex is transferred to water and exchangeable protons within amino acids that are protected by the antibody complex undergo deuterium-to- hydrogen back-exchange at a slower rate than exchangeable protons within amino acids that are not part of the interface. As a result, amino acids that form part of the protein/antibody interface may retain deuterium and therefore exhibit relatively higher mass compared to amino acids not included in the interface. After dissociation of the antibody, the target protein is subjected to protease cleavage and mass spectrometry analysis, thereby revealing the deuterium-labeled residues which correspond to the specific amino acids with which the antibody interacts. See, e.g., Ehring (1999) Analytical Biochemistry 267: 252-259; Engen and Smith (2001 ) Anal. Chem. 73: 256A-265A.

The term "epitope" refers to a site on an antigen to which B and/or T cells respond. B- cell epitopes can be formed both from contiguous amino acids or noncontiguous amino acids juxtaposed by tertiary folding of a protein. Epitopes formed from contiguous amino acids are typically retained on exposure to denaturing solvents, whereas epitopes formed by tertiary folding are typically lost on treatment with denaturing solvents. An epitope typically includes at least 3, and more usually, at least 5 or 8-10 amino acids in a unique spatial conformation.

One can easily determine whether an antibody binds to the same epitope as, or competes for binding with, a reference anti-SARS-CoV-2-S antibody by using routine methods known in the art. For example, to determine if a test antibody binds to the same epitope as a reference anti-SARS-CoV-2-S antibody of the invention, the reference antibody is allowed to bind to a SARS-CoV-2 spike protein or peptide under saturating conditions. Next, the ability of a test antibody to bind to the SARS-CoV-2 spike protein molecule is assessed. If the test antibody is able to bind to SARS-CoV-2-S following saturation binding with the reference anti-SARS- CoV-2-S antibody, it can be concluded that the test antibody binds to a different epitope than the reference anti-SARS-CoV-2-S antibody. On the other hand, if the test antibody is not able to bind to the SARS-CoV-2 spike protein following saturation binding with the reference anti- SARS-CoV-2- S antibody, then the test antibody may bind to the same epitope as the epitope bound by the reference anti-SARS-CoV-2-S antibody of the invention.

To determine if an antibody competes for binding with a reference anti-SARS-CoV-2-S antibody, the above-described binding methodology is performed in two orientations: In a first orientation, the reference antibody is allowed to bind to a SARS-CoV-2 spike protein under saturating conditions followed by assessment of binding of the test antibody to the SARS- CoV-2-S molecule. In a second orientation, the test antibody is allowed to bind to a SARS- CoV-2-S molecule under saturating conditions followed by assessment of binding of the reference antibody to the SARS-CoV-2-S molecule. If, in both orientations, only the first (saturating) antibody is capable of binding to the SARS-CoV-2-S molecule, then it is concluded that the test antibody and the reference antibody compete for binding to SARS- CoV-2-S. As will be appreciated by a person of ordinary skill in the art, an antibody that competes for binding with a reference antibody may not necessarily bind to the identical epitope as the reference antibody, but may sterically block binding of the reference antibody by binding an overlapping or adjacent epitope.

Two antibodies bind to the same or overlapping epitope if each competitively inhibits (blocks) binding of the other to the antigen. That is, a 1 -, 5-, 10-, 20- or 100-fold excess of one antibody inhibits binding of the other by at least 50% but preferably 75%, 90% or even 99% as measured in a competitive binding assay (see, e.g., Junghans et al., Cancer Res. 1990 50:1495-1502). Alternatively, two antibodies have the same epitope if essentially all amino acid mutations in the antigen that reduce or eliminate binding of one antibody reduce or eliminate binding of the other. Two antibodies have overlapping epitopes if some amino acid mutations that reduce or eliminate binding of one antibody reduce or eliminate binding of the other.

Additional routine experimentation (e.g., peptide mutation and binding analyses) can then be carried out to confirm whether the observed lack of binding of the test antibody is in fact due to binding to the same epitope as the reference antibody or if steric blocking (or another phenomenon) is responsible for the lack of observed binding. Experiments of this sort can be performed using ELISA, RIA, surface plasmon resonance, flow cytometry or any other quantitative or qualitative antibody-binding assay available in the art.

Immunoconjugates

The invention encompasses a human anti-SARS-CoV-2-S monoclonal antibody conjugated to a therapeutic moiety ("immunoconjugate"), such as a toxoid or an anti-viral drug to treat COVID 19 infection. As used herein, the term "immunoconjugate" refers to an antibody which is chemically or biologically linked to a radioactive agent, a cytokine, an interferon, a target or reporter moiety, an enzyme, a peptide or protein or a therapeutic agent. The antibody may be linked to the radioactive agent, cytokine, interferon, target or reporter moiety, enzyme, peptide or therapeutic agent at any location along the molecule so long as it is able to bind its target.

Examples of immunoconjugates include antibody drug conjugates and antibody-toxin fusion proteins. In one embodiment, the agent may be a second different antibody to SARS-CoV-2 spike protein. In certain embodiments, the antibody may be conjugated to an agent specific for a virally infected cell. The type of therapeutic moiety that may be conjugated to the anti- SARS-CoV-2-S antibody and will take into account the condition to be treated and the desired therapeutic effect to be achieved. Examples of suitable agents for forming immunoconjugates are known in the art; see for example, WO 05/103081.

Multi-specific Antibodies

The antibodies of the present invention may be mono-specific, bi-specific, or multi- specific. Multi-specific antibodies may be specific for different epitopes of one target polypeptide or may contain antigen-binding domains specific for more than one target polypeptide. See, e.g., Tutt et al. , 1991 , J. Immunol. 147:60-69; Kufer et al. , 2004, Trends Biotechnol. 22:238- 244.

Any of the multi-specific antigen-binding molecules of the invention, or variants thereof, may be constructed using standard molecular biological techniques (e.g., recombinant DNA and protein expression technology), as will be known to a person of ordinary skill in the art.

In some embodiments, SARS-CoV-2-S-specific antibodies are generated in a bi-specific format (a "bi-specific") in which variable regions binding to distinct domains of SARS-CoV-2 spike protein are linked together to confer dual-domain specificity within a single binding molecule. Appropriately designed bi-specifics may enhance overall SARS-CoV-2-spike- protein inhibitory efficacy through increasing both specificity and binding avidity. Variable regions with specificity for individual domains, (e.g., segments of the N-terminal domain), or that can bind to different regions within one domain, are paired on a structural scaffold that allows each region to bind simultaneously to the separate epitopes, or to different regions within one domain. In one example for a bi-specific, heavy chain variable regions (VH ) from a binder with specificity for one domain are recombined with light chain variable regions (VL ) from a series of binders with specificity for a second domain to identify non-cognate VL partners that can be paired with an original VH without disrupting the original specificity for that VH . In this way, a single VL segment (e.g., /J ) can be combined with two different VH domains (e.g., VH 1 and VH 2) to generate a bi- specific comprised of two binding "arms"

(VH 1 - VL 1 and VH 2- VL 1). Use of a single VL segment reduces the complexity of the system and thereby simplifies and increases efficiency in cloning, expression, and purification processes used to generate the bi-specific (See, for example, USSN 13/022759 and US2010/0331527).

In some embodiments, SARS-CoV-2-S-specific antibodies are generated in a trii-specific format (a "tri-specific") in which variable regions binding to distinct domains of SARS-CoV-2 spike protein are linked together to confer triple-domain specificity within a single binding molecule.

Alternatively, antibodies that bind more than one domains and a second target, such as, but not limited to, for example, a second different anti-SARS-CoV-2-S antibody, may be prepared in a bi-specific format using techniques described herein, or other techniques known to those skilled in the art. Antibody variable regions binding to distinct regions may be linked together with variable regions that bind to relevant sites on, for example, the extracellular domain of SARS-CoV-2-S, to confer dual-antigen specificity within a single binding molecule. Appropriately designed bi-specifics of this nature serve a dual function. Variable regions with specificity for the extracellular domain are combined with a variable region with specificity for outside the extracellular domain and are paired on a structural scaffold that allows each variable region to bind to the separate antigens.

The invention provides therapeutic compositions comprising the anti-SARS-CoV-2-S antibodies or antigen-binding fragments thereof of the present invention. Therapeutic compositions in accordance with the invention will be administered with suitable carriers, excipients, and other agents that are incorporated into formulations to provide improved transfer, delivery, tolerance, and the like. A multitude of appropriate formulations can be found in the formulary known to all pharmaceutical chemists: Remington's Pharmaceutical Sciences, Mack Publishing Company, Easton, PA. These formulations include, for example, powders, pastes, ointments, jellies, waxes, oils, lipids, lipid (cationic or anionic) containing vesicles (such as LIPOFECTIN™), DNA conjugates, anhydrous absorption pastes, oil-in- water and water-in-oil emulsions, emulsions carbowax (polyethylene glycols of various molecular weights), semi-solid gels, and semi-solid mixtures containing carbowax. See also Powell et al. "Compendium of excipients for parenteral formulations" PDA (1998) J Pharm Sci Technol 52:238-31 1.

The dose of antibody may vary depending upon the age and the size of a subject to be administered, target disease, conditions, route of administration, and the like. When an antibody of the present invention is used for treating a disease or disorder in an adult patient, or for preventing such a disease, it is advantageous to administer the antibody of the present invention normally at a single dose of about 0.1 to about 60 mg/kg body weight, more preferably about 5 to about 60, about 10 to about 50, or about 20 to about 50 mg/kg body weight. Depending on the severity of the condition, the frequency and the duration of the treatment can be adjusted. In certain embodiments, the antibody or antigen-binding fragment thereof of the invention can be administered as an initial dose of at least about 0.1 mg to about 800 mg, about 1 to about 500 mg, about 5 to about 300 mg, or about 10 to about 200 mg, to about 100 mg, or to about 50 mg. In certain embodiments, the initial dose may be followed by administration of a second or a plurality of subsequent doses of the antibody or antigen-binding fragment thereof in an amount that can be approximately the same or less than that of the initial dose, wherein the subsequent doses are separated by at least 1 day to 3 days; at least one week, at least 2 weeks; at least 3 weeks; at least 4 weeks; at least 5 weeks; at least 6 weeks; at least 7 weeks; at least 8 weeks; at least 9 weeks; at least 10 weeks; at least 12 weeks; or at least 14 weeks.

Various delivery systems are known and can be used to administer the pharmaceutical composition of the invention, e.g., encapsulation in liposomes, microparticles, microcapsules, recombinant cells capable of expressing the mutant viruses, receptor mediated endocytosis (see, e.g., Wu et al. (1987) J. Biol. Chem. 262:4429-4432). Methods of introduction include, but are not limited to, intradermal, transdermal, intramuscular, intraperitoneal, intravenous, subcutaneous, intranasal, epidural and oral routes. The composition may be administered by any convenient route, for example by infusion or bolus injection, by absorption through epithelial or mucocutaneous linings (e.g., oral mucosa, rectal and intestinal mucosa, etc.) and may be administered together with other biologically active agents. Administration can be systemic or local. The pharmaceutical composition can be also delivered in a vesicle, in particular a liposome (see, for example, Langer (1990) Science 249:1527-1533).

The use of nanoparticles to deliver the antibodies of the present invention is also contemplated herein.

In certain situations, the pharmaceutical composition can be delivered in a controlled release system. In one embodiment, a pump may be used. In another embodiment, polymeric materials can be used. In yet another embodiment, a controlled release system can be placed in proximity of the composition's target, thus requiring only a fraction of the systemic dose.

The injectable preparations may include dosage forms for intravenous, subcutaneous, intracutaneous, intracranial, intraperitoneal and intramuscular injections, drip infusions, etc. These injectable preparations may be prepared by methods publicly known. For example, the injectable preparations may be prepared, e.g., by dissolving, suspending or emulsifying the antibody or its salt described above in a sterile aqueous medium or an oily medium conventionally used for injections. As the aqueous medium for injections, there are, for example, physiological saline, an isotonic solution containing glucose and other auxiliary agents, etc., which may be used in combination with an appropriate solubilizing agent such as an alcohol (e.g., ethanol), a polyalcohol (e.g., propylene glycol, polyethylene glycol), a nonionic surfactant [e.g., polysorbate 80, HCO-50 (polyoxyethylene (50 mol) adduct of hydrogenated castor oil)], etc. As the oily medium, there are employed, e.g., sesame oil, soybean oil, etc., which may be used in combination with a solubilizing agent such as benzyl benzoate, benzyl alcohol, etc. The injection thus prepared is preferably filled in an appropriate ampoule.

Advantageously, the pharmaceutical compositions for oral or parenteral use described above are prepared into dosage forms in a unit dose suited to fit a dose of the active ingredients. Such dosage forms in a unit dose include, for example, tablets, pills, capsules, injections (ampoules), suppositories, etc. The amount of the antibody contained is generally about 5 to about 500 mg per dosage form in a unit dose; especially in the form of injection, it is preferred that the antibody is contained in about 5 to about 100 mg and in about 10 to about 250 g for the other dosage forms.

Therapeutic Uses of the Antibodies

The antibodies of the present invention are useful for the treatment, and/or prevention of a disease or disorder or condition associated with COVID 19-coronavirus such as COVID 19 infection and/or for ameliorating at least one symptom associated with such disease, disorder or condition. In one embodiment, an antibody or antigen-binding fragment thereof the invention may be administered at a therapeutic dose to a patient with COVID 19 infection.

In certain embodiments, the antibodies of the invention are useful to treat subjects suffering from the severe and acute respiratory infection caused by COVID 19-coronavirus. In some embodiments, the antibodies of the invention are useful in decreasing viral titer or reducing viral load in the host. In one embodiment, the antibodies of the present invention are useful in preventing or reducing inflammation in the lung of a subject with COVID 19. In one embodiment, the antibodies of the present invention are useful in preventing or reducing interstitial, peribronchiolar or perivascular inflammation, alveolar damage and pleural changes in a subject with COVID 19.

One or more antibodies of the present invention may be administered to relieve or prevent or decrease the severity of one or more of the symptoms or conditions of the disease or disorder. The antibodies may be used to ameliorate or reduce the severity of at least one symptom of COVID 19 infection including, but not limited to consisting of fever, cough, shortness of breath, pneumonia, diarrhea, organ failure (e.g., kidney failure and renal dysfunction), septic shock, loss of smell, loss of taste and death.

It is also contemplated herein to use one or more antibodies of the present invention prophylactically to subjects at risk for developing COVID 19 infection such as immunocompromised individuals, elderly adults (more than 65 years of age), children younger than 2 years of age, healthcare workers, persons with occupational or recreational contact with camels or bats, family members in close proximity to a COVID 19 patient, adults or children with contact with persons with confirmed or suspected COVID 19 infection, and patients with a medical history (e.g., increased risk of pulmonary infection, heart disease or diabetes).

In a further embodiment of the invention the present antibodies are used for the preparation of a pharmaceutical composition or medicament for treating patients suffering from COVID 19 infection. In another embodiment of the invention, the present antibodies are used as adjunct therapy with any other agent or any other therapy known to those skilled in the art useful for treating or ameliorating COVID 19 infection.

Combination Therapies

Combination therapies may include an anti-SARS-CoV-2-S antibody of the invention and any additional therapeutic agent that may be advantageously combined with an antibody of the invention, or with a biologically active fragment of an antibody of the invention. The antibodies of the present invention may be combined synergistically with one or more drugs or therapy used to treat COVID 19. In some embodiments, the antibodies of the invention may be combined with a second therapeutic agent to reduce the viral load in a patient with COVID 19 infection, or to ameliorate one or more symptoms of the infection.

The antibodies of the present invention may be used in combination with an anti inflammatory drug (e.g., corticosteroids, and non-steroidal anti-inflammatory drugs), an anti- infective drug, a different antibody to SARS-CoV-2 spike protein, an anti-viral drug, interferon- alpha-2b plus intramuscular ribavirin, convalescent plasma, an inhibitor of the main viral protease, and entry/fusion inhibitors targeting the SARS-CoV-2 spike protein, hydroxychloroquine, chloroquine, remdesivir, a vaccine for SARS-CoV-2, antibiotics, a dietary supplement such as anti-oxidants or any other palliative therapy to treat COVID 19 infection.

In certain embodiments, the second therapeutic agent is another antibody to SARS-CoV-2 spike protein. It is contemplated herein to use a combination ("cocktail") of antibodies with broad neutralization or inhibitory activity against SARS-CoV-2. In some embodiments, non competing antibodies may be combined and administered to a subject in need thereof, to reduce the ability of COVID 19 virus to escape due to rapid mutation as a result of selection pressure. In some embodiments, the antibodies comprising the combination bind to distinct non-overlapping epitopes on the spike protein. The antibodies comprising the combination may block the SARS-CoV-2 binding to ACE2 or may prevent/inhibit membrane fusion.

It is also contemplated herein to use a combination of anti-SARS-CoV-2-S antibodies of the present invention, wherein the combination comprises one or more antibodies that do not cross-compete; In some embodiments, the combination includes a first antibody with broad neutralization activity with a second antibody with activity against a narrow spectrum of isolates and that does not cross-compete with the first antibody.

As used herein, the term "in combination with" means that additional therapeutically active component(s) may be administered prior to, concurrent with, or after the administration of the anti-SARS-CoV-2-S antibody of the present invention. The term "in combination with" also includes sequential or concomitant administration of an anti-SARS-CoV-2-S antibody and a second therapeutic agent.

The additional therapeutically active component(s) may be administered to a subject prior to administration of an anti-SARS-CoV-2-S antibody of the present invention. In other embodiments, the additional therapeutically active component(s) may be administered to a subject after administration of an anti-SARS-CoV-2-S antibody of the present invention. In yet other embodiments, the additional therapeutically active component(s) may be administered to a subject concurrent with administration of an anti-SARS-CoV-2-S antibody of the present invention.

The present invention includes pharmaceutical compositions in which an anti-SARS-CoV-2-S antibody of the present invention is co-formulated with one or more of the additional therapeutically active component(s) as described elsewhere herein.

Methods of diagnosis

The anti-SARS-CoV-2-S antibodies of the present invention may be used to detect and/or measure SARS-CoV-2 in a sample, e.g., for diagnostic purposes. Some embodiments contemplate the use of one or more antibodies of the present invention in assays to detect a disease or disorder such as viral infection. Exemplary diagnostic assays for SARS-CoV-2 may comprise, e.g., contacting a sample, obtained from a patient, with an anti-SARS-CoV-2- S antibody of the invention, wherein the anti-SARS-CoV-2-S antibody is labeled with a detectable label or reporter molecule or used as a capture ligand to selectively isolate SARS- CoV-2 from patient samples. Alternatively, an unlabeled anti-SARS-CoV-2-S antibody can be used in diagnostic applications in combination with a secondary antibody which is itself detectably labeled. The detectable label or reporter molecule can be a radioisotope, such as ³H,¹⁴C,³²P,³⁵S, or ¹²⁵l ; a fluorescent or chemiluminescent moiety such as fluorescein isothiocyanate, or rhodamine; or an enzyme such as alkaline phosphatase, b-galactosidase, horseradish peroxidase, or luciferase. Specific exemplary assays that can be used to detect or measure SARS-CoV-2 in a sample include enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA), and fluorescence-activated cell sorting (FACS).

Samples that can be used in SARS-CoV-2 diagnostic assays according to the present invention include any tissue or fluid sample obtainable from a patient, which contains detectable quantities of either SARS-CoV-2 spike protein, or fragments thereof, under normal or pathological conditions. Generally, levels of SARS-CoV-2 spike protein in a particular sample obtained from a healthy patient (e.g., a patient not afflicted with a disease associated with SARS-CoV-2) will be measured to initially establish a baseline, or standard, level of SARS-CoV-2. This baseline level of SARS-CoV-2 can then be compared against the levels of SARS-CoV-2 measured in samples obtained from individuals suspected of having a SARS-CoV-2-associated condition, or symptoms associated with such condition.

The antibodies specific for SARS-CoV-2 spike protein may contain no additional labels or moieties, or they may contain an N-terminal or C-terminal label or moiety. In one embodiment, the label or moiety is biotin. In a binding assay, the location of a label (if any) may determine the orientation of the peptide relative to the surface upon which the peptide is bound. For example, if a surface is coated with avidin, a peptide containing an N-terminal biotin will be oriented such that the C-terminal portion of the peptide will be distal to the surface.

EXAMPLES

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how to make and use the methods and compositions of the invention, and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers used (e.g., amounts, temperature, etc.) but some experimental errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, molecular weight is average molecular weight, temperature is in degrees Centigrade, room temperature is about 25°C, and pressure is at or near atmospheric.

Example 1 Generation of Human Antibodies to SARS-CoV-2 spike protein

We collected cross-sectional blood samples from three PCR-confirmed SARS-CoV-2-infected individuals (COSCA1-3) approximately four weeks after symptom onset. COSCA1 (47-year- old male) and COSCA2 (44-year-old female) showed symptoms of an upper respiratory tract infection and mild pneumonia, respectively (Table 1). Both remained in home-isolation during the course of COVID-19 symptoms. COSCA3, a 69-year-old male, developed severe pneumonia and was admitted to the intensive care unit one and a half weeks after symptom onset to be put on mechanical ventilation. To identify S protein-specific antibodies in serum, we generated soluble prefusion-stabilized S proteins of SARS-CoV-2 using stabilization strategies as previously described for S proteins of SARS-CoV-2 and other b-coronaviruses (Fig. 1) (12, 31). As demonstrated by the size-exclusion chromatography (SEC) trace, SDS- and blue-native PAGE, the resulting trimeric SARS-CoV-2 S proteins were of high purity. Sera from all patients showed strong binding to the S protein of SARS-CoV-2 in ELISA with endpoint titers of 13637, 6133, and 48120 for COSCA1, COSCA2 and COSCA3, respectively and had varying neutralizing potencies against SARS-CoV-2 pseudovirus with reciprocal serum dilutions giving 50% inhibition of virus infection (ID50) of 383, 626 and 7645 for COSCA1-3, respectively. In addition, all sera showed cross-reactivity to the S protein of SARS-CoV and neutralized SARS-CoV pseudovirus, albeit with lower potency. The potent S protein-specific binding and neutralizing responses observed for COSCA3 are in line with earlier findings that severe disease is associated with a strong humoral response (32). These strong serum binding and neutralization titers prompted subsequent sorting of SARS-CoV-2 S protein-specific B cells for mAb isolation from COSCA1-3.

Peripheral blood mononuclear cells (PBMCs) were stained with dually fluorescently labelled prefusion SARS-CoV-2 S proteins and analyzed for the frequency and phenotype of specific B cells by flow cytometry. The analysis revealed a high frequency of S protein-specific B cells (S-AF647+, S-BV421+) among the total pool of B cells (CD19+Via-CD3-CD14-CD16-), ranging from 0.68-1.74%. These SARS-CoV-2 S-specific B cells showed a predominant memory (CD20+CD27+) and plasmablasts/plasma cell (PB/PC) (CD20-CD27+CD38+) phenotype with an average 3-fold significant enrichment of specific B cells in the PB/PC compartment. COSCA3, who experienced severe symptoms, showed the highest frequency of PB/PC in both total (34%) and specific (60%) B-cell compartments. As expected, the SARS-CoV-2 S protein- specific B cells were enriched in the lgG+ and lgM-/lgG- (most likely representing lgA+) B cell populations, although a substantial portion of the specific B cells were lgM+, particularly for COSCA3.

Table 1. COVID-19 patient specifics. The numbers indicate the day of symptom onset and relief, treatment period and sampling time point in days following symptom onset. ICU: intensive care unit. NSAIDs: nonsteroidal anti-inflammatory drugs.

Patient samples

Sera and PBMCs were collected through the COVID-19 Specific Antibodies (COSCA) study. Both outpatients and clinical patients aged between 18 and 75 years, with at least one nasopharyngeal swab positive for SARS-CoV-2 as determined by qRT-PCR (Roche LightCycler480, targeting the Envelope-gene 113bp), were included in this observational study with interventional measures after signing written informed consent. Patients were excluded when using immunosuppressive medication (equivalent of >7.5 mg prednisolone). The COSCA study was conducted at the Amsterdam University Medical Centre, location AMC (AMC), The Netherlands and approved by the local ethical committee of the AMC (NL 73281.018.20). Approximately four weeks after onset of COVID-19 symptoms, patient demographics and a medical history were obtained and a venapuncture was performed for the collection of blood in Acid Citrate Dextrose tubes for the isolation of PBMCs and collection of serum.

Construct design

To create the prefusion S ectodomain of SARS-CoV-2 similar stabilizations, a gene encoding residues 1-1138 (Wuhan-Hu-1 ; GenBank: MN908947.3) with proline substitutions at amino acid positions 986 and 987 ( 36 ) and a “GGGG” substitution at the furin cleavage site (amino acids 682-685) was ordered (Genscript). The gene was then cloned by Pstl-BamHI digestion and ligation into pPPI4 plasmids (37) containing a T4 trimerization domain followed by a Strep- tag® II or hexahistidine tag. For the prefusion S ectodomain of SARS-CoV, a gene encoding residues 1-1120 (Frankfurt-1 strain; GenBank: AAP33697.1) with proline substitutions at amino acid positions 968 and 969 was ordered and cloned into the same pPPI4 plasmid (Genscript). To generate proteins for B cell sorting the prefusion S ectodomain of SARS-CoV-2 was cloned by Pstl-BamHI digestion and ligation into a pPPI4 plasmid containing a trimerization domain followed by an Avi- and hexahistidine tag. A gene encoding amino acids 319-541 (SARS-CoV- 2) and 306-527 (SARS-CoV) were ordered to generate the receptor binding domains (RBD) of SARS-CoV-2 and SARS-CoV, respectively (38), and cloned directly downstream of a TPA leader signal into a pPPI4 plasmid containing an octahistidine tag.

Protein expression and purification

All constructs were expressed transiently in HEK293F (Invitrogen, cat no. R79009) cells maintained in Freestyle medium (Life Technologies). Cells were transfected at a density of 0.8- 1.2 million cells/mL by addition of a mix of PEImax (1 pg/mI) with expression plasmids (312.5 pg/l) in a 3:1 ratio in OptiMEM. Supernatants of glycoproteins were harvested six days post transfection, centrifuged for 30 min at 4000 rpm and filtered using 0.22 pm Steritop filters (Merck Millipore). Constructs with a Strep-tag II were purified by affinity purification using Strep- TactinXT Superflow high capacity 50% suspension according to the manufacturer's protocol for gravity flow (IBA Life Sciences). Biolock solution and a 10X buffer W (1 M Tris/HCI, 1.5 M NaCI, 10 mM EDTA, pH 8.0) were diluted 1:1000 and 1 :10, respectively, in the filtered supernatant prior to column loading. Constructs with a his-tag were purified by affinity purification using Ni-NTA agarose beads. Protein eluates were concentrated and buffer exchanged to PBS using Vivaspin filters with a 100 kDa molecular weight cutoff (GE Healthcare). Protein concentrations were determined by the Nanodrop method using the proteins peptidic molecular weight and extinction coefficient as determined by the online ExPASy software (ProtParam).

SDS-PAGE and BN-PAGE analysis

SDS-PAGE and BN-PAGE were performed as described previously (39). Briefly, for SDS- PAGE 2.5 pg of denatured S protein was loaded on a 4-12% Tris-Glyine (Invitrogen). For BN- PAGE, 2.5 pg of S protein was mixed with loading dye and ran on a 4-12% Bis-Tris NuPAGE gel (Invitrogen).

The biological properties of the exemplary antibodies generated in accordance with the methods of this Example are described in detail in the Examples set forth below.

Example 2: Characterization of the antibodies

SARS-CoV-2 S-specific B cells were subsequently single cell sorted for mAb isolation. In total, 409 paired heavy chain (HC) and light chain (LC) were obtained from the sorted B cells of the three patients (137, 165, and 107 from COSCA1-3, respectively), of which 323 were unique clonotypes. Clonal expansion occurred in all three patients, but was strongest in COSCA3 where it was dominated by HC variable (VH) regions VH3-7 and VH4-39 (34% and 32% of SARS-CoV-2 S-specific sequences, respectively). Even though substantial clonal expansion occurred in COSCA3, the median somatic hypermutation (SHM) was 1.4%, with similar SHM in COSCA1 and COSCA2 (2.1% and 1.4%). These SHM levels are similar to those observed in response to infection with other respiratory viruses (33).

A hallmark of antibody diversity is the heavy chain complementarity determining region 3 (CDRH3). Since the CDRH3 is composed of V, D and J gene segments, it is the most variable region of an antibody in terms of both amino acid composition and length. The average length of CDRH3 in the naive human repertoire is 15 amino acids {34), but for a subset of influenza virus and HIV-1 broadly neutralizing antibodies, long CDRH3 regions of 20-35 amino acids are crucial for high affinity antigen-antibody interactions {35, 36). Even though the mean CDRH3 length of isolated SARS-CoV-2 S protein-specific B cells did not differ substantially from that of a naive population {34), we observed a significant difference in the distribution of CDRH3 length (two sample Kolmogorov-Smirnov test, p = 0.006). This difference in CDRH3 distribution can largely be attributed to an enrichment of longer (~20 amino acid) CDRH3s, leading to a bimodal distribution as opposed to a bell-shaped distribution that was observed in the naive repertoire.

Next, to determine SARS-CoV-2-specific signatures in B cell receptor (BCR) repertoire usage, we compared IMGT-assigned unique germline V regions from the sorted SARS-CoV-2 S- specific B cells to the well-defined extensive germline repertoire mentioned above {34). In particular VH1-69 and VH3-33 were strongly enriched in COSCA1-3 patients compared to the naive repertoire (by 41and 14-fold, respectively). The enrichment of VH1-69 has been shown in response to a number of other viral infections, including influenza virus, hepatitis C virus and rotavirus (37), but the enrichment of VH3-33, apparent in all three patients, appears to be specific for COVID-19. In contrast, VH4-34 and VH3-23 were substantially underrepresented in SARS-CoV-2-specific sequences compared to the naive repertoire (8-fold and 4-fold decrease in frequency, respectively). While the usage of most VH genes was consistent between COVID-19 patients, particularly VH3-30-3 and VH4-39 showed considerable variance. Thus, upon SARS-CoV-2 infection the S protein recruits a subset of B cells from the naive repertoire enriched in specific VH segments and CDRH3 domains.

B cell sorting

Biotinylated recombinant SARS-CoV-2 S proteins were conjugated with a streptavidin fluorophore resulting in fluorescent labelled-probes. In short, the recombinant proteins were conjugated in a 7:1 ratio to the streptavidin-conjugates AF647 (0.5 mg/ml_, BioLegend) and BV421 (0.1 mg/ml_ BioLegend). The conjugation incubation took place at 4°C, for at least 1 r. Cryopreserved PBMCs from a healthy donor were thawed to serve as a control sample. Both PBMCs from the healthy donor and from the convalescent patients were stained for 30 min at 4°C with the conjugated proteins, a live/dead marker (viability-eF780, eBiosciences) and the following surface markers: CD19-AF700 (HIB19, BioLegend), CD20-PE-CF594 (2H7, BD Biosciences), CD27-PE (L128, BD Biosciences), CD38-BB515 (HIT2, BD Biosciences), IgM- BV605 (MHM-88, BioLegend), lgG-PE-Cy7 (G18-145, BD Biosciences), and various surface markers with the same fluorophore APC-eF780 to eliminate all non-B cells, the “dump” channel, including T cell markers CD3 (UCHT1, eBiosciences ) and CD4 (OKT4, eBiosciences), monocyte and macrophage marker CD14 (C1 D3, eBiosciences), and NK-cell marker CD16 (CB16, eBiosciences). Following three washes in PBS (Dulbecco’s Phosphate- Buffered Saline, eBiosciences) supplemented with 1 mM EDTA and 2% fetal calf serum, flow cytometry was performed on a 4-laser FACS ARIA (BD Biosciences). Live B cells that were double positive for the SARS-CoV-2 S protein (AF647 and BV421) were single cell sorted using index sorting into a 96-well plate containing lysis buffer to maintain the RNA. The lysis buffer consisted of 20 U RNAse inhibitor (Invitrogen), first strand Superscript III buffer (Invitrogen), 1.25 pi of 0.1 M DTT (Invitrogen), in a total volume of 20 mI. The plates with the sorted single cells were stored at -80°C for at least 1 h before performing the reverse transcriptase (RT)-PCR to transcribe the mRNA to cDNA. The analysis of the surface markers of the SARS-CoV-2 positive cells was performed on FlowJo (version 10.6).

Antibody cloning

The mRNA of the lysed SARS-CoV-2 S protein specific single B cells was converted into cDNA by performing an RT-PCR. Briefly, 50 U Superscript III RTase (Invitrogen), 2 mI of 6mM dNTPs (Invitrogen), and 200 ng random hexamer primers (Thermo Scientific) in a total volume of 6 mI was added to the plate containing sorted cells and lysis buffer. The RT program was set as followed: 10 min at 42°C, 10 min 25°C, 60 min at 50°C, 5 min at 95°C, and infinity 4°C. The cDNA was stored at -20°C until further analysis. The V(D)J variable regions of the antibodies are amplified from the SARS-CoV-2-specific single cell sorted B cells, as previously described (40). Briefly, for both kappa and lambda chain PCR 1 was performed with 0.5 U MyTaq polymerase (BioLine), 0.1 mM of both forward and reverse multiplex primers (40), MyTaq PCR reaction buffer (BioLine), and 2 mI of cDNA in a total volume of 20 mI for 1 min 95°C, 50 cycles of 15 s at 95°C, 15 s at 58°C, 45 s at 72°C, followed by 10 min at 72°C. The nested PCR was performed with 0.375 U HotStarTaq Plus polymerase (Qiagen), 0.2 mM dNTPs, 0.034 mM of both forward and reverse multiplex primers (40), Hotstar Taq Plus PCR buffer (Qiagen), and 2 mI of PCR 1 product in a total volume of 14.5 mI for 5 min at 95°C, 50 cycles of 30 s at 94°C, 30 s at 60°C, 1 min at 72°C, followed by 10 min at 72°C. For the heavy chain a primary and two nested PCR reactions were performed. Briefly, the primary PCR was performed with 0.375 U HotstarTaq Plus polymerase (Qiagen), 0.2 mM dNTPs, 0.069 mM of both forward and reverse multiplex primers (40), Hotstar Taq Plus PCR buffer (Qiagen), and 2 mI of cDNA in a total volume of 14.5 mI for 5 min at 95°C, 50 cycles of 30 s at 94°C, 30 c at 52°C, 1 min at 72°C, followed by 10 min at 72°C. The first nested PCR was performed with 0.5 U MyTaq polymerase (Bioline), 0.05 mM of both forward and reverse multiplex primers (40), MyTaq PCR reaction buffer (BioLine), and 2 mI of PCR 1 product in a total volume of 20 mI for 1 min 95°C, 30 cycles of 15 s at 95°C, 15 s at 58°C, 45 s at 72°C, followed by 10 min at 72°C. The final PCR, was performed with 0.375 U HotStarTaq Plus polymerase (Qiagen), 0.2 mM dNTPs, 0.034 mM of both forward and reverse multiplex primers with vector overhang, Hotstar Taq Plus PCR buffer (Qiagen), and 2 pi of PCR 2 product in a total volume of 14.5 mI_ for 5 min at 95°C, 50 cycles of 30 s at 94°C, 30 s at 60°C, 1 min at 72°C, followed by 10 min at 72°C.

Antibody cloning and small-scale expression

All recombinant antibodies were expressed in a mammalian cell expression system as described previously (16, 41). Briefly, the variable V(D)J-region of the heavy and light chain of the antibody were cloned into correspondingly expression vectors containing the constant regions of the human lgG1 for the heavy or light chain using Gibson Assembly (42). The Gibson Assembly was carried out with a home-made Gibson mix consisting of 2x Gibson mix (0.2 U T5 exonuclease (Epibio), 12.5 U Phusion polymerase (New England Biolabs), Gibson reaction buffer (0.5 g PEG-8000 (Sigma Life Sciences), 1 M Tris/HCI pH 7.5, 1 M MgCI₂, 1 M DTT, 100 mM dNTPs, 50 mM NAS (New England Biolabs), MQ)) and performed for 60 min at 50°C. The sequence integrity of the plasmids was verified by Sanger sequencing. For small- scale transfection, adherent HEK293T cells (ATCC, CRL-11268) were maintained in Dulbecco’s Modified Eagle’s Medium (DMEM) supplemented with 10% fetal calf serum (FCS), penicillin (100 U/mL), and streptomycin (100 pg/mL) and transfected as described previously (39). 24 h prior to transfection, HEK293T cells were seeded in 24-well plates at a density of 2.75x10⁵ cells per well in complete medium as described above. The transfection mix consisted of a 1:1 (w:w) HC/LC ratio using a 1 :2.5 ratio with 1 mg/L PEImax (Polysciences) in 200 pL Opti-MEM. After 15 minute incubation at RT, the transfection mix was added onto the cells. Supernatants were harvested 48 h post-transfection and clarified supernatants were tested by enzyme-linked immunosorbent assay (ELISA).

ELISA screening of mAbs

Strep ll-tagged SARS-CoV-2 S proteins were diluted to a concentration of 2.0 pg/mL in casein (ThermoFisher) and immobilized on streptavidin-coated 96-well plates (ThermoFisher) for 2 h at RT. Next, undiluted supernatants were added to the wells and binding was allowed for 2 h at RT. Then, a 1:3000 dilution of horseradish peroxidase (HRP)-labeled goat anti-human IgG (Jackson Immunoresearch) in casein was added for 1 h at RT. Up to this point, in between each step, the plates were washed three times with TBS. Finally, after washing the plates five times with TBS/0.05% Tween-20, developing solution (1% 3,3’,5,5’-tetramethylbenzidine (Sigma-Aldrich), 0.01% hydrogen peroxide, 100 mM sodium acetate and 100 mM citric acid) was added. Development of the colorimetric endpoint proceeded for 4 min before termination by adding 0.8 M sulfuric acid. Larger-scale antibody expression and purification

For larger-scale expression of selected mAbs, suspension HEK293F cells (Invitrogen, cat no. R79007) were cultured in Freestyle medium (Gibco) and co-transfected with the two IgG plasmids expressing the corresponding HC and LC in a 1:1 ratio at a density of 0.8-1.2 million cells/mL in a 1 :3 ratio with 1 mg/L PEImax (Polysciences). The recombinant IgG antibodies were isolated from the cell supernatant after five days as described previously (16, 41). In short, the cell suspension was centrifuged 30 min at 4000 rpm, and the supernatant was filtered using 0.22 pm pore size SteriTop filters (Millipore). The filtered supernatant was run over a 25 ml_ protein A/G column (Pierce) followed by two column volumes of PBS wash. The antibodies were eluted with 0.1 M glycine pH 2.5, into the neutralization buffer 1 M TRIS pH 8.7 in a 1:9 ratio. The purified antibodies were buffer exchanged to PBS using 50 kDa VivaSpin20 columns (Sartorius). The IgG concentration was determined on the NanoDrop 2000 and the antibodies were stored at 4°C until further analyses.

Example 3: Heavy and Light Chain Variable Region Amino Acid Sequences Genetic analyses of BCR repertoire

Heavy chain and light chain germ Line assignment, framework region annotation, determination of somatic hypermutation (SHM) levels and CDR loop lengths was performed with the aid of IMGT/HighV-QUEST (www.imqt.org/HiqhV-QUEST). Sequences were aligned using MAFFT (v.7, www.mafft.cbrc.jp/alignment/software/). Maximum likelihood phylogenetic analysis was performed with MEGA X (Molecular Evolutionary Genetics Analysis). For comparison, the naive repertoire of three representative donors was used (30). Antibody clonotypes were defined as a set of sequences that share genetic V and J regions as well as an identical CDRH3. To determine whether CDRH3 lengths between a naive repertoire and isolated mAbs were significantly different, a two-sample Kolgomorov-Smirnov (K-S) test was used. Analysis and handling of datasets was performed using RStudio 1.2.1335 (R 3.6.1).

Table 2 sets forth the amino acid sequence identifiers of the heavy and light chain variable regions and CDRs of selected anti-SARS-CoV-2-S antibodies of the invention.

Table 3 sets forth the amino acid sequences of CDRL2s of selected anti-SARS-CoV-2- S antibodies of the invention.

Example 4: Antibody binding to SARS-CoV-2-S as determined by Surface Plasmon

Resonance

Subsequently, all HC and LC pairs were transiently expressed in HEK293T cells and screened for binding by ELISA to SARS-CoV-2 S protein. We obtained few S protein-reactive mAbs from COSCA3, possibly because the majority of B cells from this individual were lgM+, complicating the cloning of the V regions into an IgG backbone. 84 mAbs that showed potent binding were selected for small-scale expression in HEK 293F cells and purified. Surface plasmon resonance (SPR) assays showed binding of 77 mAbs to S protein with binding affinities in the nano- to picomolar range (Table 4). To gain insight in the immunodominance of the RBD as well as the ability to cross-react with SARS-CoV, we assessed the binding capacity of these mAbs to the prefusion S proteins and the RBDs of SARS-CoV-2 and SARS-CoV by ELISA. Of the 84 mAbs that were tested, 32 (38%) bound to the SARS-CoV-2 RBD with 7 mAbs (22%) showing cross-binding to SARS-CoV RBD. Interestingly, we also observed 33 mAbs (39%) that bound strongly to SARS-CoV-2 S but did not bind the RBD, of which 10 mAbs (30%) also bound to the S protein of SARS-CoV. Notably, some Abs that bound very weakly to soluble SARS-CoV-2 S protein in ELISA showed strong binding to membrane-bound S protein, implying that their epitopes are presented poorly on the stabilized soluble S protein (Table 4).

Sensor preparation for surface plasmon resonance (SPR) mAbs were diluted in 10 mM sodium acetate buffer pH 4.5 + 0.075% Tween-80 to a concentration of 50 nM. Continuous flow microspotting was used to deposit an array of mAbs on the SPR sensor (Ssens). The first 48 mAbs were spotted in the lower half of the sensing area for 5 min, while the second 48 mAbs were spotted in the upper half of the sensing area for 10 min to account for decrease in activity of sensor surface chemistry. For kinetic screening, a P-Easy-2-Spot SPR sensor was used, for epitope binning, a G-Easy-2-Spot SPR sensor was used. After creating the array, the sensor was installed in the IBIS MX96 SPR Imager (IBIS Technologies) and deactivated for 7 minutes with 100 mM ethanolamine pH 8.5.

SPR measurements and data processing

Kinetic screening of the mAb panel was performed in the IBIS MX96 by injecting the S-protein antigen in a 2-fold dilution series from 128 to 1 nM in running buffer (PBS with 0.075% Tween- 80). After each antigen injection, the sensor surface was regenerated twice with 20 mM H3P04 pH 2.0 for 16 s. IBIS SPRintX software was used to process the data. Scrubbed software (BioLogic Software) was used to analyze the data and obtain kinetic information. Epitope binning of the mAb panel was performed in the IBIS MX96 by injection of cycles of premixed S-protein and mAb followed by regeneration. Premixing was done for 30 minutes at 30 nM for S-protein and 150 nM for mAb. Antigen and mAbs were premixed prior to injection over the antibody array to allow complete occupation of identical binding sites on the S-protein trimer. Interspersed injections of S-protein antigen were used during the measurement to account for drift and/or loss of antigen-binding capacity of the sensor. The data from the binning run was processed using IBIS SPRintX software and analyzed by IBIS using Binning Tool Software (Carterra Inc, USA). Briefly, the antigen-only injections were used to normalize all responses to a value of 1. An analysis window was placed at the end of the association phase (t=300 [BAI] seconds, Arthur?) where binding or blocking of the mAb1 sensor-(Ag-mAb2 injection) complex could be investigated. Heatmaps and node plots were generated using the Binning Tool Software.

Fab preparation To generate Fab fragments, mAbs were incubated for 5 h at 37°C with papain resin (50 pi settled resin/mg of mAb) in PBS, 10 mM EDTA, 20 mM cysteine, pH 7.4. Next, Fc and non- digested Abs were removed from the flow-through by a 2 h incubation at RT with 200 ul of protein A resin per mg of initial mAb (Thermo Scientific). Finally, the flow-through containing Fab fragments was buffer exchanged to TBS using Vivaspin filters with a 10 kDa molecular weight cutoff (GE Healthcare). Alternatively, his-tagged Fab constructs were expressed in HEK 293F cells as described previously with a HC Fab:LC ratio of 1:2. After 4 days of incubation, Fabs were purified by gravity flow over a Ni-NTA column (Qiagen) followed by SEC over a Superdex200 10/300 GL increase column. Serum ELISA

His-tagged SARS-CoV-2 S protein was immobilized at a concentration of 4 pg/mL in TBS on Ni-NTA plates for 2 h at RT. Plates were subsequently blocked for 30 min in TBS/2% skimmed milk, and three-fold serial dilutions of human sera, starting from a 1:50 dilution, were added in TBS+2% milk/20% sheep serum for a 2 h incubation at RT. Next, a 1:3000 dilution of HRP- labeled goat anti-human IgG (Jackson Immunoresearch) in TBS/2% skimmed milk was added for 1 h at RT. ELISA plates were washed and developed as described above.

Ni-NTA-capture ELISA

His-tagged S proteins and RBDs of SARS-CoV-2 and SARS-CoV-2 were loaded in casein (Thermo Scientific) on 96-well Ni-NTA plates (Qiagen) for 2 h at RT. After the plates were washed with TBS, three-fold serial dilutions of mAbs in casein, starting from a 10 pg/mL concentration, were added. Following three washes with TBS, a 1 :3000 dilution of HRP-labeled goat anti-human IgG (Jackson Immunoresearch) in casein was added for 1 h at RT. Colorimetric detection was performed as described above with a development time of 3.5 min.

Table 4 shows the results of the binding test described in Example 4

Example 5: Antibody-mediated neutralization of SARS-CoV-2 infectivity

All mAbs were subsequently tested for their ability to block infection. 19 mAbs (23%) inhibited SARS-CoV-2 pseudovirus infection with varying potencies of which 14 (74%) bind the RBD. Nine Abs could be categorized as potent neutralizers (IC50 < 0.1 pg/mL), three as moderate (IC50 of 0.1-1 pg/mL) and seven as weak neutralizers (IC50 of 1-10 pg/mL, Table 6). With IC50s of 0.008 pg/mL the RBD-targeting antibodies COVA1-18 and COVA2-15, in particular, were remarkably potent while being quite different in other aspects such as their heavy chain V gene usage (VH3-66 vs. VH3-23), light chain usage (VL7-46 vs. VK2-30), HC sequence identity (77%) and CDRH3 length (12 vs. 22 amino acids). Furthermore, two of the 17 mAbs that also interacted with the SARS-CoV S and RBD proteins cross-neutralized the SARS-CoV pseudovirus (IC50 of 2.5 pg/mL for COVA1-16 and 0.61 pg/mL for COVA2-02, Table 6), with COVA2-02 being more potent against SARS-CoV than against SARS-CoV-2. Next, we assessed the ability of the 19 mAbs to block infection of live SARS-CoV-2 virus. While previous reports suggest a decrease in neutralization sensitivity of primary SARS-CoV-2 in comparison to pseudovirus (25), we observed very similar potencies for the most potent mAbs (IC50s of 0.007 and 0.010 pg/mL for COVA2-15 and COVA1-18, respectively, Table 6), making them the most potent mAbs against SARS-CoV-2 described to date. NAbs COVA1-18, COVA2-07, COVA2-15, COVA2-29 and COVA2-39 also showed strong competition with ACE2 binding, further supporting that blocking ACE2 binding is their mechanism of neutralization. RBD- targeting mAb COVA2-17 however did not show any competition with ACE2. This corroborates previous observations that the RBD encompasses multiple distinct antigenic sites of which some do not block ACE2 binding (23). Interestingly, the non-RBD NAbs all bear substantially longer CDRH3s compared to RBD NAbs, suggesting a convergent CDRH3-dependent contact between antibody and epitope.

A major concern with convalescent serum treatment is ADE. We observed a low level of concentration-dependent enhancement of infection (<2-fold) for a small number of mAbs, which could indicate a possible role of the antibodies in ADE. Although, we did not observe ADE for the polyclonal sera, the observation that some mAbs have this property should induce caution when using poorly characterized convalescent plasma for therapy and supports the search for mAbs, which can be specifically selected for the desired properties of strong neutralization potency and absence of ADE.

Pseudovirus neutralization assays

Neutralization assays were based on the use of SARS-CoV and SARS-CoV-2 S-pseudotyped HIV-1 viruses and human Huh7 liver cells were performed as described previously (22). Briefly, SARS-CoV and SARS-CoV-2 S protein expression plasmids were co-transfected in 293T cells with an HIV backbone expressing firefly luciferase (pNL4-3.Luc.R-E-) (43). Cell culture supernatants containing the pseudovirus were harvested after 3 days and stored at -80C. To determine the neutralization capacity of sera and monoclonal antibodies, 20-fold diluted sera or mAbs at a starting concentration of 10 pg/mL or 1 pg/mL were serially diluted in 3-fold steps and mixed with pseudotyped virus and incubated for 1 h at 37°C. The pseudovirus serum/mAb combinations were then added to Huh7 cells which were seeded 1 day before the experiment at 10.000 cells/well. After 48 hours, the pseudovirus serum/mAb mix was removed and Bright mix (1:10 lysis buffer, 1:10 BrightGlo) was added. Luciferase activity of cell lysate was measured using a Glomax ® plate reader.

Plaque reduction neutralization test

We tested mAbs for their neutralization capacity against SARS-CoV-2 (German isolate; GISAID ID EPIJSL 406862; European Virus Archive Global #026V-03883) by using a plaque reduction neutralization test with some modifications (44). We serially diluted samples in Dulbecco modified Eagle medium supplemented with NaHCOs, HEPES buffer, penicillin, streptomycin, and 1% fetal bovine serum, starting at a dilution of 40 pg/mL in 50 mI_. We then added 50 mI_ of virus suspension (400 plaque-forming units) to each well and incubated at 37°C for 1 h before placing the mixtures on Vero-E6 cells. After incubation for 1 h, we washed cells, supplemented with medium, and incubated for 8 h. After incubation, we fixed the cells with 4% formaldehyde/phosphate-buffered saline (PBS) and stained the cells with polyclonal rabbit anti-SARS-CoV antibody (Sino Biological) and a secondary peroxidase-labeled goat anti-rabbit IgG (Dako). We developed signal by using a precipitate forming 3, 3', 5,5'- tetramethylbenzidine substrate (True Blue; Kirkegaard and Perry Laboratories) and counted the number of infected cells per well by using an ImmunoSpot Image Analyzer (CTL Europe GmbH, https://www.immunospot.eu).

Table 5 shows the neutralization potencies described in Example 5

Table 6 shows the neutralization potencies described in Example 5

Neutralization

Example 6: Characterization of competition clusters of anti-SARS-CoV-2 spike mAbs

To identify and characterize the antigenic sites on the S protein and their interrelationships we performed SPR-based cross-competition assays followed by clustering analysis. We note that competition clusters do not necessarily equal epitope clusters, but the analysis can provide clues on the relation of mAb epitopes. We identified 11 competition clusters of which nine contained more than one mAb while two contained only one mAb (clusters X and XI). All nine multiple-mAb clusters included mAbs from at least two of the three patients, emphasizing that these clusters represent common epitopes targeted by the human humoral immune response during SARS-CoV-2 infection. Three clusters included predominantly RBD-binding mAbs (clusters I, III, VII), with cluster I forming two subclusters. Four clusters (V, VI, XIII and IX) included predominantly mAbs that did not interact with RBD, and clusters II, IV, X and XI consisted exclusively of non-RBD mAbs. mAbs with diverse phenotypes (e.g. RBD and non- RBD binding mAbs) clustered together in multiple clusters, suggesting that these mAbs might target epitopes bridging the RBD and non-RBD sites or that they sterically interfere with each other’s binding as opposed to binding to overlapping epitopes. While clusters II, V and VIII contained only mAbs incapable of neutralizing SARS-CoV-2, clusters I, III, IV, VI and VII included both non-NAbs and NAbs. Interestingly, cluster V was formed by mostly non-RBD targeting mAbs cross-binding to SARS-CoV. However, these mAbs were not able to neutralize either SARS-CoV-2 or SARS-CoV, suggesting that these mAbs target a conserved non neutralizing epitope on the S protein. Finally, the two non-RBD mAbs COVA1-03 and COVA1- 21 formed unique single-mAb competition clusters (cluster X and XI, respectively) and showed an unusual competition pattern, as binding of either mAb blocked binding by majority of the other mAbs. We hypothesize that these two mAbs allosterically interfere with mAb binding by causing conformational changes in the S protein that shield or impair the majority of other mAb epitopes. COVA1-21 also efficiently blocked virus infection, suggesting an alternative mechanism of neutralization than blocking ACE2 engagement (Table 7). Overall, our data are consistent with the previous identification of multiple antigenic RBD sites for SARS-CoV-2 and additional non-RBD sites on the S protein as described for SARS-CoV and MERS-CoV (18, 29). Here, our discovery of non-RBD-targeting mAbs provides additional depth to the definition of antibody epitopes on the SARS-CoV-2 S protein.

Table 7. Competition of mAbs (top row) with ACE2 for binding to SARS-CoV-2 spike. “0” means no ACE2 can bind to the SARS-CoV-2 S protein and thus 100% competition of a particular mAb. “100” would mean all ACE2 can bind to the SARS-CoV-2 S protein and thus 0% competition of a particular mAb.

In conclusion, convalescent COVID-19 patients showed strong anti-SARS-CoV-2 S protein specific B cell responses and developed memory and antibody producing B cells that may have participated in the control of infection and the establishment of humoral immunity. We isolated 19 NAbs that target a diverse range of antigenic sites on the S protein, of which two showed picomolar neutralizing activities (IC50s of 0.007 and 0.010 pg/mL or 47 and 67 pM) against live SARS-CoV-2 virus. This illustrates that SARS-CoV-2 infection elicits high-affinity and cross-reactive mAbs targeting the RBD as well as other sites on the S protein. Several of the potent NAbs had VH segments virtually identical to their germline origin, which holds promise for the induction of similar NAbs by vaccination as extensive affinity maturation does not appear to be a requirement for potent neutralization. Interestingly, the most potent NAbs both target the RBD on the S protein and fall within the same competition cluster, but are isolated from two different individuals and bear little resemblance genotypically. Although direct comparisons are difficult, the neutralization potency of these and several other mAbs exceeds the potencies of the most advanced HIV-1 and Ebola mAbs under clinical evaluation as well as approved anti-RSV mAb palivizumab (39). Through large-scale SPR-based competition assays, we defined NAbs that target multiple sites of vulnerability on the RBD as well as additional previously undefined non-RBD epitopes on SARS-CoV-2. This is consistent with the identification of multiple antigenic RBD sites for SARS-CoV-2 and the presence of additional non-RBD sites on the S protein of SARS-CoV and MERS-CoV (29). Subsequent structural characterization of these potent NAbs will guide vaccine design, while simultaneous targeting of multiple non-RBD and RBD epitopes with mAb cocktails paves the way for safe and effective COVID-19 prevention and treatment.

Statistical analysis Midpoint serum neutralization titers (IDso-values) and midpoint mAb inhibition concentrations (IC5o-values) were determined using GraphPad Prism software (version 8.3.0). The two- sample Kolmogorov-Smirnov test to compare CDRH3 distributions was performed in RStudio 1.2.1335 (R 3.6.1).

Neutralization experiments were performed as described above for mutant variant B.1.1.7, B1.352 and P1.

PSEUDOVIRUS NEUTRALIZATION Epitope NAb ID WT B.1.1.7 B.1.351 P.1

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Claims

1. An isolated human antibody or antigen-binding fragment thereof that specifically binds to the SARS-CoV-2 spike protein.

2. The antibody or antigen-binding fragment thereof according to claim 1 , wherein the antibody or antigen-binding fragment thereof has one or more of the following characteristics: a. is a fully human monoclonal antibody; b. neutralizes SARS-CoV-2 infectivity wherein the SARS-CoV-2 comprises an isolate of the virus (German isolate; GISAID ID EPIJSL 406862; European Virus Archive Global #026V-03883); c. neutralizes SARS-CoV-2 infectivity of human host cells with IC50 less than 4.5 mM, as measured in a pseudovirus neutralization assay; d. binds to SARS-CoV-2 spike protein with a dissociation constant (KD) of less than 175 nM as measured in a surface plasmon resonance assay; e. inhibits binding of SARS-CoV-2 spike protein to ACE2 by more than 40%, as measured in a bio-layer interferometry assay; f. interacts with one or more amino acid residues in the receptor binding domain (RBD) of the SARS-CoV-2 spike protein selected from amino acid residues 319 to 529 of SEQ ID NO: 669; g. is a bi-specific antibody comprising a first binding specificity to a first epitope in the receptor binding domain of SARS-CoV-2 spike protein and a second binding specificity to a second epitope in the receptor binding domain of SARS-CoV-2 spike protein wherein the first and second epitopes are distinct and non-overlapping.

3. The antibody or antigen-binding fragment thereof according to claim 1 or 2, wherein the antibody or antigen-binding fragment: a. comprises three heavy chain complementarity determining regions (CDRs) (HCDR1, HCDR2 and HCDR3) and three light chain complementarity determining regions (LCDR1, LCDR2 and LCDR3) contained within an HCVR/LCVR amino acid sequence pair selected from the group consisting of: 329/333, 1/5, 9/13, 17/21, 25/29, 33/37, 41/45, 49/53, 57/61, 65/69, 73/77, 81/85, 89/93, 97/101, 105/109, 113/117, 121/125, 129/133, 137/141, 145/149, 153/157, 161/165, 169/173, 177/181, 185/189, 193/197, 201/205, 213/209, 217/221, 225/229, 233/237, 241/245, 249/253, 257/261, 265/269, 273/277, 281/285, 289/293, 297/301, 305/309, 313/317, 321/325, 337/341, 345/349, 353/357, 361/365, 369/373, 381/385, 389/393, 397/401, 405/409, 413/417, 421/425, 429/433, 437/441, 445/449, 453/457, 461/465, 469/473, 477/481, 485/489, 493/497, 501/505, 509/513, 517/521, 525/529, 533/537, 541/545, 549/553, 557/561, 565/569, 573/577, 581/585, 589/593, 597/601, 605/609, 613/617, 621/625, 629/633, 637/641 , 645/649, 653/657 and 661/665 b. competes for binding to SARS-CoV-2-S with an antibody or antigen-binding fragment of (a); or, c. binds to the same epitope as an antibody or antigen-binding fragment of (a).

4. The antibody or antigen-binding fragment thereof according to claim 3, wherein said HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 329/333, 369/373, 137/141, 265/269, 517/521, 161/165, 89/93, 121/125, 241/245, 169/173, 345/349, 17/21, 249/253, 437/441, 193/197, 313/317, 297/301, 501/505 and 225/229.

5. The antibody or antigen-binding fragment thereof according to claim 3 or 4, wherein said HCVR/LCVR amino acid sequence pair is selected from the group consisting of SEQ ID NOs: 329/333, 137/141, 265/269, 517/521, 161/165, 89/93, 121/125, 241/245, 345/349, 17/21, 169/173 and 249/253.

6. The antibody or antigen-binding fragment thereof according to claim 5, comprising a set of six CDRs (HCDR1-HCDR2-HCDR3-LCDR1-LCDR2-LCDR3) selected from the group consisting of SEQ NOs: 330-331-332-334-335-336, 138-139-140- 142-143-144, 266-267-268-270-271-272, 518-519-520-522-523-524, 162-163- 164-166-167-168, 90-91-92-94-95-96, 122-123-124-126-127-128, 242-243-244- 246-247-248, 346-347-348-350-351-352, 18-19-20-22-23-24, 170-171-172-174- 175-176 and 250-251-252-254-255-256.

7. The antibody or antigen-binding fragment of claim 5, comprising a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 329/333, 137/141, 265/269, 517/521, 161/165, 89/93, 121/125 and 241/245.

8. The antibody or antigen-binding fragment of claim 7, comprising a HCVR/LCVR amino acid sequence pair selected from the group consisting of SEQ ID NOs: 329/333 and 137/141.

9. The antibody of any one of claims 1-8 which is a recombinant antibody.

10. The antibody of any one of claims 1-9 which is a full-length antibody.

11. A pharmaceutical composition comprising an antibody or antigen-binding fragment thereof according to any one of claims 1-10 and a pharmaceutically acceptable carrier or diluent.

12. An isolated polynucleotide molecule comprising a polynucleotide sequence that encodes a HCVR or a LCVR of an antibody or antigen-binding fragment thereof according to any one of claims 1-10; a vector comprising the polynucleotide sequence; or a cell expressing the vector.

13. An antibody or antigen-binding fragment thereof of any one of claims 1-10 or a pharmaceutical composition of claim 11 for use in a method of preventing, treating or ameliorating at least one symptom or indication of SARS-CoV-2 infection.

14. A method of diagnosing a SARS-CoV-2 -related disease or disorder, the method comprising:, a. contacting a test sample obtained from a patient suspected of having the coronavirus-related disease or disorder with an antibody or antigen-binding fragment thereof of any one of claims 1-9; and, b. detecting the presence or absence of an antibody-antigen complex, wherein the presence of the antibody-antigen complex indicates that the patient has the SARS-CoV-2 -related disease or disorder.