WO2021214039A1 - Spla2hgib-binding molecules and uses thereof - Google Patents

Abstract

The present invention relates to sPLA2hGIB-binding molecules and their uses for modulating an immune response in a subject in need thereof. The invention also relates to compositions comprising such molecules, and uses thereof for inhibiting the enzymatic activity of sPLA2hGIB and for treating disorders associated with an immune deficiency. More specifically, the invention concerns the production and characterization of novel chimeric receptors PLA2R1 with a modified CTLD5 domain.

Description

sPLA2hGIB-BINDING MOLECULES AND USES THEREOF

FIELD OF THE INVENTION

The present invention relates to sPLA2hGIB-binding molecules and their uses, in particular for modulating an immune response in a subject in need thereof. The invention also relates to compositions comprising such molecules, such as pharmaceutical compositions, and the uses thereof, e.g., for treating disorders associated with an immune deficiency. More specifically, the invention concerns the production and characterization of novel chimeric receptors based on PLA2R1 with a modified CTLD5 domain.

BACKGROUND OF THE INVENTION

Fluman secreted phospholipase A2 group IB (sPLA2hGIB) is a low molecular weight (14 kDa), highly stable (7 disulfide bonds) secreted protein that catalyzes the hydrolysis of the sn-2 fatty acyl bond of phospholipids to release free fatty acids and lysophospholipids (Lambeau& Gelb 2008). In humans, the PLA2GIB gene is mainly expressed in the pancreas, with weaker expression levels in the duodenum, jejunum, and stomach (Eskola et al. 1983a) (Nevalainen & Haapanen 1993). Marginal expression has been described in other tissues, such as lung, eyes (Kolko et al. 2007) and testis. In human pancreas, sPLA2hGIB is mostly synthesized in apical zymogen granule portion of pancreatic acinar cells (Eskola et al. 1983a). sPLA2hGIB has also been detected in insulin secretory granules of pancreatic islet b-cells and is co-secreted with insulin from glucose-stimulated islets (Ramanadham et al. 1998). sPLA2hGIB is secreted from exocrine pancreas as an inactive proenzyme (pro-sPLA2hGIB), which is activated by proteolytic cleavage of the N-terminal propeptide by trypsin or related enzymes, leading to the active mature secreted form (sPLA2hGIB). For instance, in vitro experiments suggested that trypsin and plasmin are able to activate pro-sPLA2hGIB in pancreas and lung (Nakano et al. 1994). In addition to a role in the gastrointestinal tract, sPLA2hGIB is also circulating in human plasma ((Nishijima et al. 1983) (Eskola et al. 1983b) (Sternby 1984) (Nevalainen et al. 1985) (Kitagawa et al. 1991)).

The inventors have previously characterized sPLA2hGIB as a key endogenous factor of the immune response (W02015/097140). More particularly, they demonstrated that sPLA2hGIB plays a crucial role in the mechanism underlying the unresponsiveness of CD4 T cells observed for example in viremic HIV-infected patients. It was thus proposed and documented by the inventors that sPLA2hGIB modulators are effective for stimulating the immune system in a subject, especially for the treatment of diseases associated with an immune deficiency. Examples of such sPLA2hGIB modulators are disclosed for instance in W02015/097140, W02017/037041, W02017/060405, WO2019/166664 or WO2019/166665. The SPLA2GIB modulators may be SPLA2GIB inhibitors or ligands selected from anti-sPLA2hGIB antibodies or derivatives thereof, inhibitory nucleic acids, peptides, small drugs or soluble receptors.

Continuing their research, applicant has now produced and characterized novel sPLA2hGIB- binding molecules, which can inhibit human SPLA2GIB and represent valuable immune stimulating compounds.

SUMMARY OF THE INVENTION

An object of the invention relates to a sPLA2hGIB-binding molecule, wherein said molecule comprises at least a C-type lectin-like domain 5 (CTLD5) domain of a phospholipase A2 receptor 1 (PLA2R1).

In a particular embodiment, the sPLA2hGIB-binding molecule comprises a modified CTLD5 of phospholipase A2 receptor 1 (PLA2R1), such as a chimeric CTLD5 domain. The modified CTLD5 domain may be a CTLD5 domain in which one or more amino acid residues are substituted or deleted or inserted. The chimeric CTLD5 domain may be a CTLD5 domain from a mammalian species in which one or more amino acid residues are replaced by corresponding amino acid residues of a CTLD5 domain from (an)other mammalian species. Examples include rodent/human chimeric CTLD5 domains, which comprise a rodent CTLD5 domain modified with human amino acid residues; or human/rodent chimeric CTLD5 domains, which comprise a human CTLD5 domain modified with rodent amino acid residues. Modified/deleted/replaced amino acid residue(s) is(are) preferably in regions of CTLD5 selected from long loop region 1 (LLR1), long loop region 2 (LLR2), β4, α 1 and/or α1C1.

Particular sPLA2hGIB-binding molecules of the invention further comprise a CTLD5-linker.

Other preferred molecules of the invention further comprise a CTLD3 and/or a CTLD4 domain.

Other preferred molecules of the invention may further comprise a CTLD-3 linker and/or a CTLD4-linker.

A further object of the invention relates to an sPLA2hGIB-binding molecule comprising, consisting essentially of, or consisting of CTLD3, CTLD4 and CTLD5 domains, which may originate from same or different mammalian species and/or be modified, independently from each other.

Preferred sPLA2hGIB-binding molecules of the invention do not comprise a transmembrane domain and/or a CTLD1 and/or CTLD2 and/or CTLD6 and/or CTLD7 and/or CTLD8 domain(s). A further object of the invention relates to a nucleic acid construct encoding a sPLA2hGIB- binding molecule as described herein.

A further object of the invention relates to a vector comprising the nucleic acid construct as described herein or expressing a sPLA2hGIB-binding molecule as described herein.

A further object of the invention relates to a host cell expressing a sPLA2hGIB-binding molecule as described herein. Preferably, the host cell is a mammalian cell.

A further object of the invention relates to a method of expressing a sPLA2hGIB-binding molecule comprising the following steps: (i) culturing a host cell expressing the sPLA2hGIB- binding molecule as described herein, under condition suitable for the expression of said molecule, and (ii) recovering the sPLA2hGIB-binding molecule.

A further object of the invention relates to a composition comprising a sPLA2hGIB-binding molecule as described herein, or a nucleic acid encoding such a molecule, and a pharmaceutically acceptable carrier.

Further objects of the invention relate to the uses of sPLA2hGIB-binding molecules, coding nucleic acids, and pharmaceutical compositions, as described herein, particularly as a medicament and/or to inhibit an activity of sPLA2hGIB. Preferred uses include the stimulation of an immune response in a subject in need thereof, the induction or activation of CD4 T cells in a subject, as well as the treatment of an infectious disease (such as AIDS), an immune disorder, an immunodeficiency or a cancer.

Another object of the invention relates to a method of treating a subject in need for such treatment, comprising administering to the subject an effective amount of a sPLA2hGIB-binding molecule as described herein.

Another object of the invention relates to the use of a sPLA2hGIB-binding molecule as described herein for the manufacture of a medicament for use for treating a subject in need thereof.

The invention may be used in any mammal. It is particularly suited for use in human subjects.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1: General scheme of generation of novel chimeric PLA2R1 that bind to sPLA2hGIB. (A) The objective of this study was to transfer hGIB binding capacity from m(mouse)PLA2Rl (which binds sPLA2hGIB) to hPLA2Rl (which poorly binds sPLA2hGIB), in order to develop a new hGIB inhibitor for therapeutic uses in humans; (B) During this study, about 100 mutants were generated and transiently transfected into COS cells, and their affinity was assessed by DELFIA^® and AlphaLISA^® tests. A series of deletion mutants allowed to demonstrate that the CTLD3-4-5 domains of mPLA2Rl contain the hGIB binding site. A series of chimeras between mouse and human PLA2R1 showed that the transfer of mCTLD5 from mPLA2Rl into hPLA2Rl expressed as a CTLD3-CTLD5 triple domain is sufficient to confer high affinity for sPLA2hGIB.

Figure 2: Principle of measurement of binding between mPLA2Rl and sPLA2hGIB. Competition of different phospholipase inhibitors with sPLA2hGIB or sPLA2hGIIF binding to full mPLA2Rl. The sPLA2hGIB binding to the whole extracellular part of FIA-tagged mPLA2Rl is measured using AlphaLISA^® technology. FIA-labeled mPLA2R receptors are placed in the presence of sPLA2hGIB or sPLA2hGIIF, followed by a specific biotinylated anti-sPLA2 antibody, "acceptor" beads conjugated to an anti-FIA antibody (PerkinElmer), and "donor" beads conjugated to streptavidin (PerkinElmer). The binding of a FIA-labeled receptor and sPLA2 in solution leads to the close proximity of donor and acceptor beads, thus allowing oxygen energy transfer and production of light.

Figure 3: Chimeric PLA2R1 receptors. (A) Among more than 100 constructions developed by the inventors, two chimeric proteins: Protein3 and Protein4 are represented, that are secreted soluble proteins comprising three CTLD domains. Protein3 essentially consists of CTLD3 and CTLD4 domains of a human PLA2R1 (hPLA2Rl), the CTLD5-linker region and the mouse CTLD5 domain in which the regions LLR1, LLR2 and beta-4 have been humanized. Protein4 consists essentially of CTLD3, CTLD4 and CTLD5 domains of a human PLA2R (hPLA2Rl), wherein the CTLD5-linker region and the alpha-helix 1 of CTLD5, have been murinized; (B) Affinity of murine and human PLA2R1 proteins, Protein3 and Protein4 to sPLA2hGIB, measured by tests using AlphaLISA^® and DELFIA^® techniques. Percentages of total identity between chimeric proteins and hPLA2Rl are shown in columns 4 and 5. Identity shown is either on the domains CTLD3-4-5 (hC345, column 4) or CTLD5 alone (hC5, column 5); (C) Focus on the CTLD5 domain of PLA2R1 constructions. Alignment of the amino acid sequences of CTLD5 domains of Protein 3 and Protein4 (SEQ ID NO: 3 and 4, respectively) with the parent mouse and human sequences (SEQ ID NO: 47 and 46, respectively). The amino acids that differ from the sequence of the human CTLD5, are shown in red.

Figure 4: Cloning and partial purification of Protein3. Schematic representation of chimeric Protein3 inserted into the expression vector pcDNA3.1/Zeo. The insert codes for Protein3 which is secreted thanks to the signal peptide of sPLA2hGIIA, and contains the 6xHIS and 3xFlag tags at the N-terminal end, and an HA tag at the C-terminal end; (B) After purification from culture media (CM from transiently transfected COS cells with a Mock construction (empty vector) or with the Protein3 construction) with His-Tag beads (Roche), imidazole elutions were pooled, desalted and concentrated. Aliquots of culture medium (CM), elution buffer alone (EB), and concentrated elutions of control (Mock) or protein3 conditions, were separated by SDS-PAGE on two gels loaded in parallel. One was silver colored (left), the other was transferred to a PVDF membrane and analyzed by Western Blot (WB, right). The protein of interest has an apparent molecular mass of about 65 kDa (dotted line). The purified fraction contains the partially purified chimeric Protein3 present at a ratio of about 1/200 among total proteins, with an estimated concentration of about 10 nM.

Figure 5: Inhibition of the enzymatic activity of sPLA2hGIB by Protein 3. Enzymatic activity assays for sPLA2hGIB was performed as described by Rouault, et al., 2006. The condition "no hGIB" (0%) represents the non-specific hydrolysis of phospholipids from E. coli membranes radiolabelled with [³H]oleate; the condition "hGIB" (100%) represents sPLA2hGIB activity alone (10 pM). sPLA2hGIB was preincubated with different amounts of Protein3, the Mock control fraction or with commercially available recombinant pure mPLA2Rl as a control ("RMS", #5367- PL, R&D Systems). In this test, the maximal final concentration of the chimeric Protein3 has been estimated between 1 to 5 nM.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to novel molecules which bind to sPLA2hGIB and are able to inhibit an activity of sPLA2hGIB. The invention also relates to the use of these sPLA2hGIB-binding molecules in vitro or in vivo, particularly as a medicament, such as for stimulating an immune response in a subject in need thereof and for inducing or activating CD4 T cells. The molecules and compositions of the invention are particularly useful in the treatment of disorders associated with an immune deficiency, including infectious diseases, immune disorders, immunodeficiency or cancer, in a subject in need thereof.

The inventors have previously identified sPLA2hGIB as playing a crucial role in the mechanism underlying the unresponsiveness of CD4 T cells in various pathological situations such as during infectious disease (e.g., viral infections, bacterial infections, etc.) or cancers, for instance. The inventors have also demonstrated that inhibition of sPLA2hGIB leads to a remarkable stimulation of immune function and correction of such disorders. The inventors have now generated and characterized novel sPLA2hGIB-binding molecules. Said molecules can inhibit sPLA2hGIB and can be used to modulate an immune response. These molecules have been typically derived or designed from PLA2R1 receptor, and exhibit improved binding capacity and inhibition properties. More preferably, said molecules comprise a CTLD5 domain, which may be modified. These molecules allow efficient inhibition of sPLA2hGIB and represent novel potent therapeutic agents.

Definitions

The term "inhibitor of sPLA2hGIB" designates any molecule or treatment which causes (directly or indirectly) an inhibition of the expression or a function of sPLA2hGIB. Inhibiting sPLA2hGIB designates preferably reducing by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or more the expression or an activity of sPLA2hGIB, as well as completely blocking or suppressing said expression or activity. Depending on the situation, the inhibition may be transient, sustained or permanent. Within the context of the present invention, "modulation of an immune response" designates any modification of the amount or activity or ratio of immune cells, preferably white blood cells (e.g., T lymphocytes, B lymphocytes, NK, NKT cells, macrophages, dendritic cells). In a particular embodiment, modulating an immune response includes modulating the amount or activity of T lymphocytes, preferably of CD4-T lymphocytes.

The term "sequence identity" as applied to nucleic acid or protein sequences, refers to the quantification (usually percentage) of nucleotide or amino acid residue matches between at least two sequences aligned using a standardized algorithm such as Smith-Waterman alignment (Smith and Waterman (1981) J Mol Biol 147:195-197), CLUSTALW (Thompson et al. (1994) Nucleic Acids Res 22:4673-4680), or BLAST2 (Altschul et al. (1997) Nucleic Acids Res 25:3389- 3402). BLAST2 may be used in a standardized and reproducible way to insert gaps in one of the sequences in order to optimize alignment and to achieve a more meaningful comparison between them. Sequence identity is typically determined over the entire length of a sequence. sPLA2hGIB-binding molecules

The inventors have surprisingly discovered that sPLA2hGIB-binding molecules can be generated from the PLA2R1 receptors, which are particularly efficient at inhibiting sPLA2hGIB.

PLA2R1 is a receptor first identified as a 180 kDa protein in rabbit skeletal muscle cells using the snake venom sPLA2s OS1 and OS2 (Lambeau et al., 1994). Later studies indicated that the receptor is expressed in several tissues, including lung, kidney, spleen, and colon, from different mammalian species. The M-type receptor is structurally similar to the macrophage mannose receptor, the DEC-205 receptor, and the endo-180 receptor, which all belong to a particular subgroup within the C-type lectin superfamily (Rouault et al., 2007). This receptor is a type I membrane glycoprotein comprising a single transmembrane domain, a short cytoplasmic tail, and a very large extracellular region comprising an N-terminal cysteine-rich domain, a fibronectin-like type II domain, and a tandem repeat of eight different C-type lectin-like carbohydrate recognition domains (CTLDs), designated CTLD1, CTLD2, CTLD3, CTLD4, CTLD5, CTLD6, CTLD7 and CTLD8. PLA2R1 also exists as a soluble protein comprising a cysteine-rich domain, a fibronectin-like type II domain and eight CTLD domains. The soluble form does not contain a transmembrane domain.

As used herein, the term "PLA2R1" designates any phospholipase A2 receptor 1. The term PLA2R1 includes any form of the protein, such as the membrane and/or soluble form, from any mammal species such as human or mouse. An illustrative example of a human PLA2R1 typically comprises the amino acid sequence of SEQ ID NO: 46 or any naturally-occurring variants or polymorphisms thereof. An illustrative example of a murine PLA2R1 typically comprises the amino acid sequence of SEQ ID NO: 47 or any naturally-occurring variants or polymorphisms thereof.

The inventors have demonstrated that the CTLD5 domain of PLA2R1 is essential for binding of sPLA2hGIB. Particularly, the inventors have surprisingly found that a molecule comprising or consisting essentially of CTLD3, CTLD4 and CTLD5 of a PLA2 receptor exhibits effective binding to and inhibition of sPLA2hGIB. The inventors have further surprisingly found that improved binding molecules can be produced by modifying the CTLD5 domain and/or by combining CTLD domains or amino acid residues from PLA2 receptors of various species. As shown in the experimental section, such molecules can efficiently bind to and inhibit sPLA2hGIB and represent potent agents for use as medicaments.

In a first embodiment, the present invention relates to sPLA2hGIB-binding molecules comprising a CTLD5 domain of PLA2R1 receptor. The CTLD5 is located at residues 810-942 of SEQ ID NO: 46 or 47. The CTLD5 domain of PLA2R1 receptor comprises an alpha-helix motif (comprising two specific regions "alphal" and "alpha 1C1") at the amino-terminal end; a beta-strand (comprising a specific "beta 4" region) at the carboxy-terminal end; and two long loop regions (LLR) called "LLR1" and "LLR2" in the middle of the domain. CTLD5 domain is linked to CTLD4 domain through a linker region called "CTLD5-linker". The amino acid sequence of an exemplary human CTLD5 domain with a CTLD5-linker of PLA2R1 is shown below (said sequence corresponds to AA 802-942 of SEQ ID NO: 46, with a CTLD5-linker from AA 802 to AA 809):

VKPKIPFWYQYDVPWLFYQDAEYLFHTFASEWLNFEFVCSWLHSDLLTIHSAHEQEFIHSKIKALSKYGASW WIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSVSMPSICKRKKV (SEQ ID NO: 8).

The amino acid sequence of an exemplary mouse CTLD5 domain with a CTLD5-linker of PLA2R1 is shown below (said sequence corresponds to AA 802-942 of SEQID NO: 47, with a CTLD5-linker from AA 802 to AA 809): VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHSKIKGLTKYGVK WWIGLEEGGARDQIQWSNGSPVIFQNWDKGREERVDSQRKRCVFISSITGLWGTESCSVPLPSICKRVKI (SEQ ID NO: 9).

The invention shows that amino acid residues of particular interest for improving binding to sPLA2hGIB are located in the following regions of CTLD5 domain of PLA2R1: the al and α1C1 regions of the a-helix (in bold), the β4 region of the beta-strand (underlined), the LLR1 region (bold and underlined), the LLR2 region (bold and underlined), and the CTLD5-linker region (double underlined) (see also Figure 3C). Other amino acid residues of interest are amino acid residues at positions AA 814, AA 821, AA 851, AA 854, AA 865, AA 867, AA 871, AA 872, AA 896, AA 940, AA 942 of PLA2R1 (see Figure 3C). The position of such residues of interest in SEQ ID NOs: 8 and 9, respectively, is provided in the following table:

Within the context of the present invention, "a modified CTLD5 domain" is a C-type lectin-like domain 5 (CTLD5) of PLA2 receptor (with or without a CTLD5-linker), from any mammal species such as a human or mouse, in which one or more amino acids is/are modified, preferably between 1 and 50 amino acids, more preferably between 1 and 20 amino acids, even more preferably 1, 2, 3, 4, 5, 6, 7, 8, 9 of 10 amino acids. Preferably, the amino acids of CTLD5 domain are modified by substitution or deletion. In a particular embodiment, amino acids of the CTLD5 domain are substituted by amino acids of a CTLD5 domain from a different species. In such a case, the modified CTLD5 domain is called a chimeric CTLD5 domain. The CTLD5-linker may be modified or not.

Particular sPLA2hGIB-binding molecules of the invention are soluble molecules comprising at least AA residues 9-141 of SEQ ID NO: 8 or 9, which may be modified, and which is devoid of at least a CTLD1 and/or a CTLD2 and/or a CTLD7 and/or a CTLD8.

In a particular embodiment, sPLA2hGIB-binding molecules are chimeric PLA2R1 receptors comprising at least a CTLD5 domain, which may be modified or not. Examples of such molecules are proteins comprising a CTLD3, a CTLD4 and a CTLD5 domains, said domains originating from at least two different mammal species. In a particular example, a molecule of the invention comprises, or consists essentially of: hCTLD3-hCTLD4-mCTLD5. In another particular embodiment, sPLA2hGIB-binding molecules are truncated PLA2R1 receptors comprising at least a CTLD5 domain, which may be modified or not, and devoid of at least CTLD1 and CTLD2 (e.g., SEQ ID NOs: 5 and 6). In a particular example, a molecule of the invention consists essentially of: mCTLD3-mCTLD4-mCTLD5 (SEQ ID NO: 6). In another particular embodiment, sPLA2hGIB-binding molecules are proteins comprising a chimeric CTLD5 domain.

In a particularly preferred embodiment of the invention, the sPLA2hGIB-binding molecules comprise a chimeric CTLD5 domain which is a murine domain in which at least the long loop region 1 (LLR1) and/or the long loop region 2 (LLR2) is/are humanized (fully or partially). Examples of sequences of such chimeric CTLD5 domains according to the invention are as follows:

SEQ ID NO: 10: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDKGREERVDSQRKRCVFISSITGLWGTESCSV

PLPSICKRVKI SEQ ID NO: 11: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGTESCSV PLPSICKRVKI

SEQ ID NO: 12: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGTESCS VPLPSICKRVKI

SEQ ID NO: 13: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGTESCSV PLPSICKRVKI

SEQ ID NO: 14: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGTESCS VPLPSICKRVKI

The amino acids represented in bold and underlined in above sequences, correspond to a human LLR1 and LLR2 region, as also shown in figure 3C. In another preferred embodiment of the invention, the sPLA2hGIB-binding molecules comprise a chimeric CTLD5 domain which is a murine domain in which at least the β4 region is humanized, fully or partially.

A sequence of such a chimeric CTLD5 domain is the following: SEQ ID NO: 15: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDKGREERVDSQRKRCVFISSITGLWGSEECSVS MPSICKRVKI

The underlined amino acids in the above sequence, correspond to a human β4 region, as also shown in figure 3C. In another embodiment of the invention, the sPLA2hGIB-binding molecules comprise a chimeric CTLD5 domain which is a murine domain in which at least the LLR1 and/or the LLR2 and the β4 region are humanized.

Examples of sequences of such chimeric CTLD5 domains according to the invention are as follows: SEQ ID NO: 16: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDKGREERVDSQRKRCVFISSITGLWGSEECSV SMPSICKRVKI

SEQ ID NO: 17: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRVKI

SEQ ID NO: 18: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGSEECS

VSMPSICKRVKI

SEQ ID NO: 19: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGSEECSV SMPSICKRVKI

SEQ ID NO: 20: VRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS Kl KG LTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCVFISSITG LWGTSEECS

VSMPSICKRVKI The amino acids represented in bold and underlined in above sequences, correspond to a human LLR1 and LLR2 region, and the underlined amino acids correspond to a human β4 region, as also shown in figure 3C.

In another preferred embodiment of the invention, the sPLA2hGIB-binding molecules comprise a chimeric CTLD5 domain which is a human domain in which at least the al region of the a-helix and/or the α1C1 region of the a-helix are murinized.

Exemplary sequences of such chimeric CTLD5 domains of the invention are provided below:

SEQ ID NO: 21: VKPKIPFWYQYDVPWLFYQDAEYLFHTHPAEWATFEFVCSWLHSDLLTIHSAHEQEFIHS KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRKKV

SEQ ID NO: 22: VKPKIPFWYQYDVPWLFYQDAEYLFHTFASEWLNFEFVCGWLRSDFLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

SEQ ID NO: 23: VKPKIPFWYQYDVPWLFYQDAEYLFHTHPAEWATFEFVCGWLRSDFLTIHSAHEQEFIHS KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRKKV

The amino acids represented in bold in the above sequence, correspond to the mouse al and α1C1 regions, as also shown in figure 3C.

In another particularly preferred embodiment of the invention, the sPLA2hGIB-binding molecules comprise a chimeric CTLD5 domain which is a human domain in which the al region of the a-helix and/or the α1C1 region of the a-helix, and the CTLD5-linker (i.e., VKPKIPFW which is double underlined) are murinized.

Exemplary sequences of such chimeric CTLD5 domains are provided below:

SEQ ID NO: 24: VRPKFPDWYQYDVPWLFYQDAEYLFHTHPAEWATFEFVCSWLHSDLLTIHSAHEQEFIHS KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRKKV

SEQ ID NO: 25: VRPKFPDWYQYDVPWLFYQDAEYLFHTFASEWLNFEFVCGWLRSDFLTIHSAHEQEFIHS KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV SEQ ID NO: 26 VRPKFPDWYQYDVPWLFYQDAEYLFHTHPAEWATFEFVCGWLRSDFLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

In another particularly preferred embodiment of the invention, the sPLA2hGIB-binding molecules comprise a chimeric CTLD5 domain which is a human domain in which the CTLD5- linker is murinized.

A sequence example of such a chimeric CTLD5 domain of the invention is provided below:

SEQ ID NO: 27: VRPKFPDWYQYDVPWLFYQDAEYLFHTFASEWLNFEFVCSWLHSDLLTIHSAHEQEFIHS KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRKKV

In addition to the (optionally modified) CTLD5 domain, the molecules of the invention may further comprise a CTLD3 domain and/or a CTLD4 domain. The CTLD3 and CTLD4 may be modified or not. They may be derived from any mammalian PLA2R1 receptor, such as a human or mouse. The CTLD3 is located at residues 513-648 of SEQ ID NO: 46 and 515-648 of SEQ ID NO: 47. The CTLD4 is located at residues 662-801 of SEQ ID NO: 46 or 47. Exemplary sequences of such CTLD3 and CTLD4 domains are provided below:

SEQ ID NO: 48 (human CTLD3):

SGCQEGWERHGGFCYKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKDSYFWIALQDQN

DTGEYTWKPVGQKPEPVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKAMSLCKQPVE SEQ ID NO: 49 (human CTLD4):

HPCYLDWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASFAHIEEENFVNELLHSKFNWTEER

QFWIGFNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKANKTLLPLHCGSKREWICKIPRD

SEQ ID NO: 50 (mouse CTLD3):

SRCPAGWERHGRFCYKIDTVLRSFEEASSGYYCSPALLTITSRFEQAFITSLISSVAEKDSYFWIALQDQNNTGE YTWKTVGQREPVQYTYWNTRQPSNRGGCVVVRGGSSLGRWEVKDCSDFKAMSLCKTPVK

SEQ ID NO: 51 (mouse CTLD4):

HPCYMDWESATGLASCFKVFHSEKVLMKRSWREAEAFCEEFGAHLASFAHIEEENFVNELLHSKFNWTQE

RQFWIGFNRRNPLNAGSWAWSDGSPVVSSFLDNAYFEEDAKNCAVYKANKTLLPSNCASKHEWICRIPRD. In preferred embodiments, the sPLA2hGIB-binding molecules of the invention comprise or consist of a CTLD3, a CTLD4 and a modified CTLD5 domain of PLA2R1. In a further preferred embodiment, the sPLA2hGIB-binding molecules of the invention do not comprise a CTLD1 and/or CTLD2 and/or CTLD6 and/or CTLD7 and/or CTLD8 domain(s). In a preferred embodiment, the sPLA2hGIB-binding molecules of the invention do not comprise a transmembrane domain.

In a particular embodiment, sPLA2hGIB-binding molecules of the invention comprise or consist of:

- human CTLD3 and CTLD4 domains,

- a murine CTLD5-linker, and

- a murine CTLD5 domain, which may be modified or not, preferably humanized, more preferably by replacement of LLR1, and/or LLR2 and/or β4 regions with respective human LLR1, LLR2 and β4 regions.

In another particular embodiment, sPLA2hGIB-binding molecules of the invention comprise or consist of:

- human CTLD3 and CTLD4 domains,

- a murine CTLD5-linker, and

- a human CTLD5 domain, which may be modified or not, preferably murinized, more preferably by replacement of al and/or α1C1 regions of the a-helix with murine al and/or α1C1 regions, respectively.

All the above CTLD domains are typically operably linked, either directly or through linker regions. They are preferably in the sequential order as defined above.

Preferably, the sPLA2hGIB-binding molecule is a soluble molecule. Such molecules generally do not comprise a transmembrane domain. They are also preferably devoid of intracytoplasmic domain.

Preferred molecules of the invention consist essentially of CTLD3-CTLD4-CTLD5, which may be modified.

Specific examples of preferred sPLA2hGIB-binding molecules of the invention include proteins comprising a sequence of SEQ ID NO: 1 or 2, or comprising a sequence having at least 80%, 85%, 90%, or more sequence identity to SEQ ID NO: 1 or 2, more preferably, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99%. A particular sPLA2hGIB-binding molecule of the invention is a protein comprising or consisting of SEQ ID NO: 1 (Proteinl).

Another particular sPLA2hGIB-binding molecule of the invention is a protein comprising or consisting of SEQ ID NO: 2 (Protein2). Another particular sPLA2hGIB-binding molecule of the invention is a protein comprising or consisting of a sequence selected from any one of SEQ ID NO: 10 to 27.

Another particular sPLA2hGIB-binding molecule of the invention is a protein comprising or consisting of a sequence of a modified CTLD5 domain without a CTLD5-linker. Examples of such modified CTLD5 domains are provided below: SEQ ID NO: 28: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDKGREERVDSQRKRCVFISSITGLWGTESCSV PLPSICKRVKI

SEQ ID NO: 29: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGTESCSV PLPSICKRVKI

SEQ ID NO: 30: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGTESCS

VPLPSICKRVKI

SEQ ID NO: 31: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGTESCSV PLPSICKRVKI

SEQ ID NO: 32: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

Kl KG LTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCVFISSITG LWGTESCS VPLPSICKRVKI SEQ ID NO: 33: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDKGREERVDSQRKRCVFISSITGLWGSEECSVS MPSICKRVKI

SEQ ID NO: 34: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDKGREERVDSQRKRCVFISSITGLWGSEECSV SMPSICKRVKI SEQ ID NO: 35: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRVKI

SEQ ID NO: 36: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCGFISSITGLWGSEECS

VSMPSICKRVKI

SEQ ID NO: 37: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGSEECSV SMPSICKRVKI

SEQ ID NO: 38: YQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHS

KIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGTSEECS VSMPSICKRVKI

SEQ ID NO: 39: YQYDVPWLFYQDAEYLFHTHPAEWATFEFVCSWLHSDLLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

SEQ ID NO: 40: YQYDVPWLFYQDAEYLFHTFASEWLNFEFVCGWLRSDFLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

SEQ ID NO: 41: YQYDVPWLFYQDAEYLFHTHPAEWATFEFVCGWLRSDFLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

SEQ ID NO: 42: YQYDVPWLFYQDAEYLFHTHPAEWATFEFVCSWLHSDLLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

SEQ ID NO: 43: YQYDVPWLFYQDAEYLFHTFASEWLNFEFVCGWLRSDFLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

SEQ ID NO: 44: YQYDVPWLFYQDAEYLFHTHPAEWATFEFVCGWLRSDFLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV SMPSICKRKKV SEQ ID NO: 45: YQYDVPWLFYQDAEYLFHTFASEWLNFEFVCSWLHSDLLTIHSAHEQEFIHS

KIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSV

SMPSICKRKKV

Accordingly, another particular sPLA2hGIB-binding molecule of the invention is a protein comprising a sequence selected from any one of SEQ ID NOs: 28 to 45.

Another object of the invention is a protein comprising or consisting of an amino acid sequence of any one of SEQ ID Nos: 1-4 and 10-45.

The binding molecules of the invention may further comprise additional functional groups or residues, such as a signal peptide, linker regions (such as CTLD3-linker, CTLD4-linker and/or CTLD5-linker), cloning sites, or tags (such as a polyhistidine-tag (preferably comprising at least 6 histidine repeats), a 3xFlag peptide, or an FIA-tag). The added residues or groups may be located at one or both terminal ends of the molecule and/or on side chains. For instance, a 3xFlag peptide may be added at the N-terminal end, and/or an FIA-tag may be added at the C-terminal end. In a particular embodiment, the signal peptide is the signal peptide of sPLA2 hGIIA (SEQ ID NO: 7: MKTLLLLAVIMIFGLLQAHGN).

In this regard, in a particular embodiment, a molecule according to the invention comprises or consists of SEQ ID NO: 3, or a sequence having at least 80%, 85%, 90%, or more sequence identity to SEQ ID NO: 3 (Protein3). SEQ ID NO: 3 is composed of SEQ ID NO: 1 with a signal peptide, a polyhistidine tag and a 3xFlag peptide at the N-terminal end, as well as an FIA-tag at the C- terminal end.

In another particular embodiment, a molecule according to the invention comprises or consists of SEQ ID NO: 4, or a sequence having at least 80%, 85%, 90%, or more sequence identity to SEQ ID NO: 4 (Protein4). SEQ ID NO: 4 is composed of SEQ ID NO: 2, with a signal peptide, a polyhistidine tag and a 3xFlag peptide at the N-terminal end, as well as an FIA-tag at the C- terminal end. sPLA2hGIB-binding molecules according to the invention bind to sPLA2hGIB. In a particular embodiment, they are able to bind sPLA2hGIB with a high affinity, i.e., an affinity in the nanomolar range or even higher, such as e.g., up to O.OlnM at least. In particular, molecules of the invention can bind sPLA2hGIB with an IC50 values comprised between 0.01 and 20 nM. As an illustration, Proteins 1-4 bind sPLA2hGIB with an IC50 value between 0.5 and 1.5 nM. The molecules of the invention may be produced by techniques known perse in the art such as chemical, biological, and/or genetic synthesis. Preferably, sPLA2hGIB-binding molecules according to the invention can be produced by any conventionally known protein expression method and purification method. For example: (i) a method for synthesizing peptides; (ii) a method for purifying and isolating them from the living body or cultured cells; or (iii) a method for producing them with the use of genetic recombination techniques; and combinations thereof and the like (for example, the standard techniques described for example in Molecular Cloning (Sambrook, J., Fritsch, E. F., Maniatis, T., Cold Spring Flarbor Laboratory Press) (1989) and Current Protocols in Molecular Biology (Ausubel, F. M., John Wiley and Sons, Inc. (1989)) can be used. In a particular embodiment, the invention relates to a method for producing sPLA2hGIB- binding molecules by expression of a coding nucleic acid in a host cell, and collection or purification of sPLA2hGIB-binding molecules. In this regard, the invention also relates to recombinant host cells comprising a nucleic acid encoding a sPLA2hGIB-binding molecule. Such host cells may be prokaryotic (such as bacteria, e.g. E.coli) or eukaryotic (such as yeast cells, insect cells, plant cells or mammalian cells such as COS cells, CFIO cells, FleLa cells, FIEK293 cells, Vero cells, Jurkat cells, NSO cells, BH K cells, MCF cells, etc.). The nucleic acid may be placed under the control of any suitable regulatory sequence, such as a promoter, terminator, and the like. Alternatively, the nucleic acid may be inserted in the host cell in a location where expression is driven by an endogenous promoter. Techniques for inserting nucleic acids in cells are well known in the art.

In this regard, the invention also relates to a method for producing a molecule as described herein comprising: (i) culturing a host cell as described herein, under condition suitable for the expression of the molecule, and (ii) recovering the molecule.

The invention also relates to a nucleic acid molecule comprising a sequence encoding a sPLA2hGIB-binding molecule of the invention. The nucleic acid may be DNA, RNA, PNA, or the like. The molecule may be single- or double-stranded, in isolated form or incorporated in a vector. The vector(s) used may be any cloning and/or expression vector(s) known in the art, namely prokaryotic vectors (such as E. coli vectors, e.g., pBLUESCRIPT or pSPORTl) or eukaryotic vectors (such as pcDNA, e.g. pcDNA 3.0, pcDNA 3.1 or pcDNA 3.2). The vector may also be a virus, cosmid, artificial chromosome, etc.

Exemplary sequences of nucleic acid molecules of the invention are provided as SEQ ID NO: 52 to 59. Compositions and methods

The invention also relates to a composition comprising a sPLA2hGIB-binding molecule as defined herein and, preferably, a diluent, excipient or carrier.

The invention particularly relates to a pharmaceutical composition comprising a sPLA2hGIB- binding molecule as defined herein and a pharmaceutically acceptable diluent, excipient or carrier.

A "pharmaceutical composition" refers to a formulation of a compound of the invention (active ingredient) and a medium or carrier generally accepted in the art for the delivery of biologically active compounds to the subject in need thereof. Such a carrier may be selected from all pharmaceutically acceptable carriers, diluents, medium or supports. Conventional pharmaceutical practice may be employed to provide suitable formulations or compositions to subjects, for example in unit dosage form.

The molecules or compositions according to the invention may be formulated in the form of ointment, gel, paste, liquid solutions, suspensions, tablets, gelatin capsules, capsules, suppository, powders, nasal drops, or aerosol, preferably in the form of an injectable solution or suspension. For injections, the compounds are generally packaged in the form of liquid suspensions, which may be injected via syringes or perfusions, for example. In this respect, the compounds are generally dissolved in saline, physiological, isotonic or buffered solutions, compatible with pharmaceutical use and known to the person skilled in the art. Thus, the compositions may contain one or more agents or excipients selected from dispersants, solubilizers, stabilizers, preservatives, etc. Agents or excipients that can be used in liquid and/or injectable formulations are notably methylcellulose, hydroxymethylcellulose, carboxymethylcellulose, polysorbate 80, mannitol, gelatin, lactose, vegetable oils, acacia, etc. The carrier can also be selected for example from methyl-beta-cyclodextrin, a polymer of acrylic acid (such as carbopol), a mixture of polyethylene glycol and polypropylene glycol, monoethanolamine and hydroxymethyl cellulose.

The compositions generally comprise an effective amount of an sPLA2hGIB-binding molecule of the invention, e.g., an amount that is effective to inhibit, directly or indirectly an activity of sPLA2hGIB and/or to stimulate immunity. The molecules of the invention are typically used in an amount effective to activate or stimulate CD4 T cells. Generally, the compositions according to the invention comprise from about 1 pg to 500 mg of a sPLA2hGIB-binding molecule, such as from 0.001-0.010.01-0.1 mg, 0.05-100 mg, 0.05-10 mg, 0.05-5 mg, 0.05-1 mg, 0.1-100 mg, 0.1- 1.0 mg, 0.1-5 mg, 1.0-10 mg, 5-10 mg, 10-20 mg, 20-50 mg or 50-100 mg, for example between 0.05 and 100 mg, preferably between 0.05 and 5 mg, for example 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4 or 5 mg. The dosage may be adjusted by the skilled person depending on the agent and the disease.

The compositions of the invention can further comprise one or more additional active compounds, for separate, simultaneous or sequential use.

Examples of additional active compounds include, but are not limited to, chemotherapeutic drug, antibiotics, antiviral agents, antiparasitic agents, or antifungal agents. In a particular embodiment, the sPLA2hGIB-binding molecule is used in combination with chemotherapy or hormonotherapy. In another particular embodiment, the sPLA2hGIB-binding molecule is used in combination with radiotherapy, ultrasound therapy or nanoparticle therapy. In another particular embodiment, the sPLA2hGIB-binding molecule is used in combination with checkpoint inhibitors, immunotherapy or anti-cancer vaccines.

In another particular embodiment, the sPLA2hGIB-binding molecule is used in combination with another inhibitor of sPLA2hGIB. Examples of such additional PLA2-GIB inhibitors are disclosed for instance in W02015/097140, W02017/037041, W02017/060405, WO2019/166664 or WO2019/166665, incorporated therein by reference. In a particular embodiment, the additional PLA2-GIB inhibitor is an antibody against PLA2-GIB, particularly a monoclonal antibody against PLA2-GIB, a chimeric antibody, an artificial antibody such a bispecific antibody, or a derivative or fragment thereof such as a ScFv, nanobody, Fab, etc. The antibody or derivative or fragment may be human or humanized. The additional sPLA2hGIB inhibitor may also be a pentapeptide inhibitor of PLA2GIB (such as a cyclic peptide selected from FLSYK, FLSYR and (2NapA)LS(2NapA)R).ln a particular embodiment, the methods or compositions of the invention use a combination of (i) an sPLA2hGIB-binding molecule as defined herein, and (ii) at least one antibody against PLA2GIB (or a derivative or fragment thereof), for example monoclonal antibody 14G9, 2B, 2B1, 2B2, 24B2, 22C6, 28A1, 28A3, 34G3 or 22H5, or a variant or fragment thereof, as disclosed in WO2019/166664 or WO2019/166665.

In a further particular embodiment, the sPLA2hGIB-binding molecule is in combination with an antibiotic, an antifungal agent, or an antivirus agent.

In another particular embodiment, the methods or compositions of the invention use a combination of (i) a sPLA2hGIB-binding molecule as defined herein, and (ii) a pentapeptide inhibitor of PLA2GIB (such as a cyclic peptide selected from FLSYK, FLSYR and (2NapA)LS(2NapA)R).

In a "combination therapy", the active agents may be used simultaneously or sequentially, together or in alternance. Each active agent may be used according to a specific schedule. In other instances, all active agents may be formulated and/or administered together, such as in a perfusion. In a further embodiment, the compound is administered prior to, during or after surgery (tumor resection or removal).

The invention also relates to a method for preparing a pharmaceutical composition, comprising (i) mixing a sPLA2hGIB-binding molecule as described herein, and a pharmaceutically acceptable diluent or excipient, and (ii) formulating the composition in any suitable form or container (syringe, ampoule, flask, bottle, pouch, etc.).

The invention also relates to a kit comprising (i) a composition comprising a sPLA2hGIB-binding molecule as described herein, (ii) at least one container, and optionally (iii) written instructions for using the kit.

Therapeutic indications

As used herein, "treatment" or "treating" refers to clinical intervention in an attempt to alter the natural course of the individual being treated, and can be performed either for preventive or curative purpose. Desirable effects of treatment include, but are not limited to, preventing occurrence or recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, preventing metastasis, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis. In some embodiments, compositions and methods of the invention are used to delay development of a disease or disorder or to slow the progression of a disease or disorder.

The sPLA2hGIB-binding molecules and compositions of the invention may be used to treat a variety of diseases, such as infectious diseases and immune diseases related to an inappropriate (e.g., defective or improper) immune response, particularly to an inappropriate CD4 T cell activity, as well as any disease where an increased immunity may ameliorate the subject condition. These diseases are sometime referred to as "immune disorders" in the present application. This includes immunodefective situations (e.g., caused by viral infection, pathogenic infection, cancer, etc.), autoimmune diseases, grafts, diabetes, inflammatory diseases, cancers, allergies, asthma, psoriasis, urticaria, eczema and the like. In this regard, the invention is directed to methods for treating the above-diseases, comprising administering an sPLA2hGIB-binding molecule to a subject in need thereof. The invention is also directed to methods for inducing CD4 T cells in a subject in need thereof, comprising administering an sPLA2hGIB-binding molecule to said subject.

In a particular embodiment, the invention is directed to methods of treating an infectious disease such as AIDS, immune disorder, immunodeficiency or cancer, in a subject in need thereof, comprising administering to the subject an effective amount of a chimeric protein as described herein, wherein said chimeric protein inhibits an enzymatic activity of sPLA2hGIB.

In another particular embodiment, the invention is directed to methods for treating an immunodeficiency or an associated disorder in a subject in need thereof, comprising administering an sPLA2hGIB-binding molecule to said subject, preferably in an amount effective to maintain/restore resistance of CD4 T cells to inactivation by PLA2-GIB.

In another particular embodiment, the invention is directed to the use of the sPLA2hGIB-binding molecule of the invention for treating any disease as disclosed herein (such as an immunodeficiency or an associated disorder, an infectious disease (such as AIDS), immune disorder, or cancer), which is resistant to the treatment with at least another sPLA2hGIB inhibitor such as, for example, a monoclonal anti-sPLA2hGIB antibody.

Immunodeficiencies and associated immune disorders

The invention is based on an inhibition of sPLA2hGIB in a subject, thereby increasing or restoring an immune activity, particularly a CD4 T cell-mediated activity. In a particular embodiment, the invention is therefore directed to methods for modulating, preferably stimulating an immune response in a subject in need thereof, comprising inhibiting GIBsPLA2 in said subject. In a particular embodiment, the invention is directed to methods for modulating white blood cells in a subject in need thereof, comprising inhibiting hGIBsPLA2 in said subject.

Examples of diseases that can benefit from sPLA2hGIB-binding molecules are all diseases with an immunodeficiency such as HIV-mediated immunodeficiency. In this regard, in a particular embodiment, the invention is directed to methods for treating an immunodeficiency or an associated disorder in a subject in need thereof, comprising inhibiting sPLA2hGIB in said subject. In another particular embodiment, the invention is directed to sPLA2hGIB-binding molecules for use for treating an immunodeficiency or an associated immune disorder in a subject in need thereof. Immunodeficiencies and associated immune disorders designate any condition or pathology characterized by and/or caused by a reduced immune function or response in a subject. Immunodeficiencies may be caused by e.g., viral infection (e.g., HIV, hepatitis B, etc.), bacterial infection, cancer, or other pathological conditions. The term "immunodeficiency- associated disorder" therefore designates any disease caused by or associated with an immunodeficiency. The invention is particularly suitable for treating immunodeficiencies related to CD4-T cells, and associated diseases. The present application indeed demonstrates that the biological effects of sPLA2hGIB are involved in CD4 T cell disease state. Accordingly, blocking the activity of sPLA2hGIB has a therapeutic benefit in subjects with altered response to cytokine causing immunodeficiency as often observed in patients infected with HIV. In a particular embodiment, the invention relates to methods of treating HIV infection in a subject by inhibiting sPLA2hGIB in the subject, preferably by administering an sPLA2hGIB- binding molecule to the subject. In some embodiments, the subject is an early HIV patient and the methods results in increasing the probability that the patient is a HIV controller. In other embodiments, the subject is a patient with low immunoreconstitution after antiretroviral treatment and/or with severe idiopatic CD4 T lymphopenia (ICL). The invention also relates to a method for increasing CD4-T cell activity in a HIV-infected subject by inhibiting sPLA2hGIB in the subject, preferably by administering an sPLA2hGIB-binding molecule to the subject. In another embodiment, the invention relates to methods of treating acute and/or chronic inflammation and processes derived from inflammatory reactions in a subject by injecting-binding molecule in the subject, either directly or associated with anti-inflammatory drugs.

The invention also provides methods of treating CD4T cell-linked immunodeficiency associated with cancer in a subject, by inhibiting sPLA2hGIB in the subject, preferably by administering an sPLA2hGIB-binding molecule to the subject.

Cancers The invention particularly relates to methods for treating cancer in a subject comprising administering to the subject a molecule that inhibits an sPLA2hGIB.

The invention also provides compositions and methods for treating cancer by increasing an immune response in the subject, comprising inhibiting hGIBsPLA2 in the subject, preferably by administering an sPLA2hGIB-binding molecule to the subject. In a particular embodiment, the invention relates to compositions and methods for treating cancer or neoplasia in a subject in need thereof, comprising administering to the subject an sPLA2hGIB-binding molecule.

The invention also relates to an sPLA2hGIB-binding molecule for use for treating cancer or neoplasia in a subject in need thereof.

In a particular embodiment, the compositions or methods of the invention are for preventing cancer or reducing the rate of cancer occurrence in a subject in need thereof, such as a subject at risk of neoplasia or cancer. In this regard, the invention can be used for treating risk factors for cancers, thereby avoiding or reducing the risk/rate of occurrence of a cancer. Such risk factors include, without limitation, oro-, gastro-, and/or intestinal inflammation and infections, such as pancreatitis.

The invention also relates to an sPLA2hGIB-binding molecule for use for preventing cancer or reducing the rate of cancer occurrence in a subject in need thereof. In another particular embodiment, the compositions and methods of the invention are for reducing the rate of cancer progression in a subject having a cancer. In another particular embodiment, the invention relates to an sPLA2hGIB-binding molecule for use for reducing the rate of cancer progression in a subject having a cancer. In another particular embodiment, the method of the invention is for reducing or preventing or treating cancer metastasis in a subject having a cancer, or for killing cancer cells. In another particular embodiment, the invention relates to an sPLA2hGIB-binding molecule for use for reducing or preventing or treating cancer metastasis in a subject having a cancer, or for killing cancer cells in a subject having a cancer. The invention may be used for treating any cancer. In a particular embodiment, the cancer is a solid cancer. The invention is also particularly suitable for treating cancers or neoplasia in subjects having a PLA2GIB-related CD4 T cell deficiency.

The invention may be used to treat cancers at any stage of development. In this regard, most solid cancer develop through four stages:

. Stage I. This stage is usually a small cancer or tumor that has not grown deeply into nearby tissues. It also has not spread to the lymph nodes or other parts of the body. It is often called early-stage cancer. . Stage II and Stage III. In general, these 2 stages indicate larger cancers or tumors that have grown more deeply into nearby tissue. They may have also spread to lymph nodes but not to other parts of the body.

. Stage IV. This stage means that the cancer has spread to other organs or parts of the body. It may also be called advanced or metastatic cancer.

Some cancers also have a stage 0. Stage 0 cancers are still located in the place they started and have not spread to nearby tissues. This stage of cancer is often highly curable, usually by removing the entire tumor with surgery.

The invention may be used for treating tumors or cancers at stage 0, I, II, III or IV. The invention may be used to prevent or reduce or treat metastasis of a cancer at stage 0, I, II or III. The invention may be used to reduce the rate of progression of a cancer at stage 0, I, II, III or IV. The invention may in particular be used for treating solid cancers selected from pancreatic cancer, melanoma, lung, oesophageal or pharyngeal cancer, retinoblastoma, liver, breast, ovary, renal, gastric, duodenum, uterine, cervical, thyroid, bladder, prostate, bone, brain or colorectal cancer.

Viral diseases

The invention may be used to treat viral diseases or viral infection in mammals. Examples of viruses that can be treated with the methods provided herein include, but are not limited to, enveloped viruses such as members of the following viral families: Retroviridae (e.g., HIV (such as HIV1 and HIV2), MLV, SIV, FIV, Human T-cell leukemia viruses 1 and 2, XMRV, and Coltiviruses (such as CTFV or Banna virus)); Togaviridae (for example, alphaviruses (such as Ross River virus, Sindbis virus, Semliki Forest Virus, O'nyong'nyong virus, Chikungunya virus, Eastern equine encephalitis virus, Western equine encephalitis virus, Venezuelan equine encephalitis virus) or rubella viruses); Flaviridae (for example, dengue viruses, encephalitis viruses (such as West Nile virus or Japanese encephalitis virus), yellow fever viruses); Coronaviridae (for example, coronaviruses such as SARS virus or Toroviruses); Rhabdoviridae (for example, vesicular stomatitis viruses, rabies viruses); Paramyxoviridae (for example, parainfluenza viruses, mumps virus, measles virus, respiratory syncytial virus, sendai virus, and metopneumovirus); Orthomyxoviridae (for example, influenza viruses); Bunyaviridae (for example, Hantaan virus, bunya viruses (such as La Crosse virus), phleboviruses, and Nairn viruses); Hepadnaviridae (Hepatitis B viruses); Herpesviridae (herpes simplex virus (HSV) 1 and HSV-2, varicella zoster virus, cytomegalovirus (CMV), HHV-8, HHV-6, HHV-7, and pseudorabies virus); Filoviridae (filoviruses including Ebola virus and Marburg virus) and Poxyiridae (variola viruses, vaccinia viruses, pox viruses (such as small pox, monkey pox, and Molluscum contagiosum virus), yatabox virus (such as Tanapox and Yabapox)). Non-enveloped viruses can also be treated with the methods provided herein, such as members of the following families: Calciviridae (such as strains that cause gastroenteritis); Arenaviridae (hemorrhagic fever viruses such as LCMV, Lassa, Junin, Machupo and Guanarito viruses); Reoviridae (for instance, reoviruses, orbiviruses and rotaviruses); Birnaviridae; Parvoviridae (parvoviruses, such as Human bocavirus adeno- associated virus); Papillomaviridae (such as papillomaviruses); Papovaviridae (papilloma viruses, polyoma viruses); Adenoviridae (adenoviruses); Picornaviridae (enteroviruses, enteric viruses, Poliovirus, coxsackieviruses, hepatoviruses, cardioviruses, aptoviruses, echoviruses, hepatitis A virus, Foot and mouth disease virus, and rhinovirus) and Iridoviridae (such as African swine fever virus). Other viruses that can be treated using the methods provided herein include unclassified viruses (for example, the etiological agents of Spongiform encephalopathies, the agent of delta hepatitis (thought to be a defective satellite of hepatitis B virus), the agents of non-A, non-B hepatitis (for instance, Hepatitis C); calciviruses (such as Norovirus, Norwalk and related viruses); Hepeviruses (such as Hepatitis E, JC and BK viruses) and astroviruses).

In a particular embodiment, the invention relates to methods of treating HIV infection in a subject by administering an sPLA2hGIB-binding molecule to the subject, optionally in combination with another sPLA2hGIB inhibitor. In some embodiments the subject is an early HIV patient and the methods result in increasing the probability that the patient is a HIV controller. In some embodiments the subject is a patient with low immunoreconstitution after antiretroviral treatment and/or with severe idiopatic CD4 T lymphopenia (ICL). The invention also relates to a method for increasing CD4-T cell activity in a HIV-infected subject by inhibiting sPLA2hGIB in the subject, by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

In another particular embodiment, the invention relates to methods of treating HCV infection in a subject by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

Bacterial / fungal diseases

Examples of infectious bacteria that can be treated with the methods provided herein include, but are not limited to, any type of Gram-positive (such as Streptococcus, Staphylococcus, Corynebacterium, Listeria, Bacillus and Clostridium) or Gram-negative bacteria (such as Porphyromonas, Salmonella, Shigella, Enterobacteriaceae, Pseudomonas, Moraxella, Helicobacter, Stenotrophomonas, acetic acid bacteria, alpha-proteobacteria, Escherichia coli, Neisseria gonorrhoeae, Neisseria meningitidis, Moraxella catarrhalis, Hemophilus influenzae, Klebsiella pneumoniae, Legionella pneumophila, Pseudomonas aeruginosa, Proteus mirabilis, Enterobacter cloacae and Serratia marcescens. Exemplary infectious bacteria include, but are not limited to: Porphyromonas gingivalis, Porphyromonas somerae, Terrisporobacter glycolicus, Aggregatibacter actinomycetemcomitans, Aggregatibacter aphrophilus, Bacteroides fragilis, Helicobacter pyloris, Borelia burgdorferi, Legionella pneumophilia, Mycobacteria sps (such as M. tuberculosis, M. avium, M. intracellulare, M. kansaii, M. gordonae), Staphylococcus aureus, Neisseria gonorrhoeae, Neisseria meningitidis, Listeria monocytogenes, Streptococcus pyogenes (Group A Streptococcus), Streptococcus agalactiae (Group B Streptococcus), Streptococcus (viridans group), Streptococcus faecalis, Streptococcus bovis, Streptococcus (anaerobic sps.), Streptococcus pneumoniae, pathogenic Campylobacter sp., Enterococcus sp., Haemophilus influenzae, Bacillus anthracis, corynebacterium diphtheriae, corynebacterium sp., Erysipelothrix rhusiopathiae, Clostridium perfringers, Clostridium tetani, Enterobacter aerogenes, Klebsiella pneumoniae, Pasturella multocida, Bacteroides sp., Fusobacterium nucleatum, Streptobacillus moniliformis, Treponema pallidium, Treponema pertenue, Leptospira, and Actinomyces israelii.

Examples of infectious fungi that can be treated with the methods provided herein include, but are not limited to, Cryptococcus neoformans, Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis, Chlamydia trachomatis, Candida albicans and Candida glabrata.

In a particular embodiment, the invention relates to methods of treating Staphylococcus infection in a subject, particularly Staphylococcus aureus infection, by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

In a particular embodiment, the invention relates to methods of treating Listeria infection in a subject, particularly Listeria monocytogenes infection, by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

In a particular embodiment, the invention relates to methods of treating Streptococcus infection in a subject, particularly Streptococcus pneumoniae infection, by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor. In a particular embodiment, the invention relates to methods of treating Bacillus infection in a subject, particularly Bacillus cereus infection, by administering to the subject an sPLA2hGIB- binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

Parasitic diseases

Examples of infectious parasites that can be treated with the methods provided herein include, but are not limited to Plasmodium falciparum and Toxoplasma gondii.

In a particular embodiment, the invention relates to methods of treating Plasmodium falciparum infection in a subject, by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

In a particular embodiment, the invention relates to methods of treating Toxoplasma gondii infection in a subject, by administering to the subject an sPLA2hGIB-binding molecule as described herein, optionally in combination with another sPLA2hGIB inhibitor.

Other disorders

The invention may be used to improve the immune system in any mammal in need thereof. It is suitable to correct undesirable effects, such as iatrogenic effect of drugs, toxins, pollutants, pesticides, etc. The invention may be used in any mammal, particularly any human.

Dosages, regimen and mode of administration

The duration, dosages and frequency of administering molecules or compositions of the invention may be adapted according to the subject and disease. The treatment may be used alone or in combination with other active ingredients, either simultaneously or separately or sequentially.

A typical regimen comprises a single or repeated administration of an effective amount of an sPLA2hGIB-binding molecule over a period of one or several days, up to one year, and including between one week and about six months. It is understood that the dosage of a molecule or composition of the invention administered in vivo will be dependent upon the age, health, sex, and weight of the recipient (subject), kind of concurrent treatment, if any, frequency of treatment, and the nature of the pharmaceutical effect desired. The ranges of effectives doses provided herein are not intended to be limiting and represent preferred dose ranges. However, the most preferred dosage will be tailored to the individual subject, as is understood and determinable by one skilled in the relevant arts (see, e.g., Berkowet et al., eds., The Merck Manual, 16th edition, Merck and Co., Rahway, N.J., 1992; Goodmanetna., eds., Goodman and Cilman's The pharmacological Basis of Therapeutics, 10th edition, Pergamon Press, Inc., Elmsford, N.Y., (2001)).

For use in the present invention, the sPLA2hGIB-binding molecule may be administered by any suitable route, by systemic injection, intramuscular, intravenous, intraarterial, intraperitoneal, cutaneous, subcutaneous, dermic, transdermic, intrathecal, intratumoral ocular (for example corneal) or rectal way, or by a topic administration on an inflammation site, and preferably by injection, such as systemic or parenteral injection or perfusion, more preferably by intramuscular or intravenous injection. Administration is typically repeated, or continuous. In a particular embodiment, the level of PLA2-GIB in the tumor or in body fluids is measured during the course of treatment to guide therapeutic regimen.

Further aspects and advantages of the invention will be disclosed in the following experimental section.

EXAMPLES

Example 1: Production of soluble forms of chimeric PLA2R1 that bind to sPLA2hGIB

The objective of this study was to generate new inhibitors of sPLA2hGIB from the phospholipase A2 receptor called PLA2R1 (Fig. 1A). The murine PLA2R1 receptor (mPLA2Rl) binds and inhibits hGIB with an affinity in the nM range while the human PLA2R1 receptor does not (Rouault et al, 2007). To develop a soluble form of human PLA2R1 able to bind hGIB with a nM affinity, of moderate molecular weight, and as humanized as possible, over 100 deletion mutants and soluble chimeric forms of hPLA2Rl and mPLA2Rl receptors have been prepared and tested for sPLA2hGIB binding by direct binding or competition binding with another sPLA2 called hGIIF. The binding of these chimeric soluble forms to hGIB was measured by two tests: (i) a solid phase test based on DELFIA^® technology, and (ii) a homogeneous test based on AlphaLISA^® technology (Fig. 2). Amplified Luminiscent Proximity Flomogeneous Assay (AlphaLISA) technology is used to study biomolecular interactions in a microplate format. In the test, the binding of the candidate molecules to sPLA2 allows energy transfer between a donor bead and an acceptor bead, and the induction of a luminescent signal. Inhibition of this interaction decreases the emission of the luminescent signal, in a measurable and dose-dependent manner. 1.1 Generation of modified forms of PLA2R1

Soluble chimeras between human PLA2R1 and mouse PLA2R1 were generated by PCR using the Phusion Site-Directed Mutagenesis Kit (Thermo Fisher Scientific, Waltham, USA), and subcloned into the pcDNA™3.1/Zeo(-) expression vector (Life Technologies, Carlsbad, USA). Chimeras all comprised the hGIIA signal peptide (Ml to N20, Uniprot P14555), a N-terminal 6xHIS and a 3xFlag tags, followed by either the sequence coding for the CTLD3-4-5 of human PLA2R1 (amino acids513-942) the sequence coding for the same domains of mouse PLA2R1 (amino acids515- 942), or a chimera between human and mouse sequences. All mutants comprise a C-terminal HA tag, and were sequenced before transfection. 1.2 Recombinant expression of sPLA2hGIB-binding molecules

COS cells were transiently transfected into COS cells using a modified DEAE-dextran protocol based on a protocol previously described (Valentin et al., 2000). COS cells were seeded into 6- well plates at 2 x 10⁵ cells/well and grown overnight in DMEM supplemented with 10% FBS and 1% penicillin/streptomycin solution. After washing with 2 mL of PBS, cells were incubated with 200 pL of a PBS solution containing 3 pg of plasmid and DEAE-Dextran at 0.5 mg/mL (chloride form, Sigma). After 30 min of incubation, cells were incubated at 37°C for 3h with "growth medium" - DMEM supplemented with 10% FBS, 1% penicillin/streptomycin and 80 pM chloroquine (diphosphate salt, Sigma). Cells were then shocked with a 10% DMSO in DMEM solution for 2.5 minutes in order to improve transfection efficiency. The day after transfection, the medium was exchanged to serum-free Optimem I medium (with 50 units/mL of penicillin and 50 pg/mL of streptomycin) and incubated for 5 days. Cell media were collected and centrifuged at 3000 g for at least 5 minutes. To test the inhibition of enzymatic activity of hGIB, chimeras were partially purified. Cell media from transfected cells were centrifuged for an additional time at lOO.OOOxg for 1 h to remove debris and microparticles. Clarified cell media were loaded onto His-Tag beads (Roche) previously equilibrated in a solution of T ris-HCL 50 mM pFI=8.0, NaCI 300 mM and CaCI2 5 mM. After washing with equilibration buffer to remove unbound protein, bound proteins were eluted with imidazole. Elutions containing PLA2R1 chimeras were identified by Western Blot, pooled, concentrated and buffer-exchanged in T ris-HCI 100 mM (pFI=8.0), CaCI2 10 mM using an ultracentrifugal Amicon^® filter. The purity of proteins was assessed by SDS-PAGE and silver staining. 1.3 Alpha LISA^® screening of soluble chimeras binding sPLA2hGIB

The binding affinity of mouse/human PLA2R1 chimeras to sPLA2hGIB were evaluated with a homemade AlphaLISA^® assay in which sPLA2hGIB was used as a competitor of binding of another sPLA2, called hGIIF, to HA-tagged chimeras and mutant PLA2R1 proteins. This assay thus uses the binding properties of the sPLA2hGIIF protein to PLA2R1 proteins from crude culture medium of transfected cells. The proximity of both proteins enables the transfer of chemical energy (oxygen transfer) between a donor and acceptor beads, and induces a luminescent signal. IC50 values for the binding of hGIB to the chimeras can be deduced from competition experiments with various concentrations of sPLA2hGIB. In this homogeneous assay, different reagents are sequentially added in « ½ AreaPlate » 96-well plates (Ref. 6005560, Perkin Elmer). The final volume of the well is 50 pL and all reagents are diluted in « Immunoassay buffer » (Ref. AL000C, Perkin Elmer). First, sPLA2hGIIF is added to a final concentration of 0.15 nM and pre-incubated 15 minutes with sPLA2hGIB as a competitor. Then 0.1% crude culture medium from COS cells transiently transfected with various FIA-tagged chimeras are added to the wells for 1 hour. After incubation, a biotinylated polyclonal antibody against sPLA2hGIIF is added to a final concentration of 1 nM, for another hour. Acceptor beads coupled to anti-FIA antibody (Ref. AL170C, Perkin Elmer), which are able to bind FIA-tagged chimeras, were then added to the well at a final concentration of 10 pg/mL, for 1.5 hour of incubation. Finally, donor beads coupled to streptavidin (Ref. 6760002, Perkin Elmer) were added to a final concentration of 20 pg/mL, for an incubation time of 30 minutes. The entire reaction steps were performed at room temperature. The reaction was protected from light as much as possible, and luminescence in plates was measured with an EnSpire plate-reader (Perkin Elmer). Calculations of the relative IC50 values were performed with GraphPad Prism 7 Software (San Diego, USA). A modified protocol was used to study the influence of competitors on the PLA2Rl-hGIB binding. In this test, the final concentration of hGIB was 0.3 nM, the anti-sPLA2 antibody was the 6F7 monoclonal antibody (developed by the inventors), and the raw COS cell culture media were used at 1% final concentration. Acceptor beads and donor beads were used at a final concentration of 10 pg/mL. Example 2: Demonstration that the presence of mouse CTLD3-CTLD4-CTLD5 domains is sufficient to bind sPLA2hGIB

The inventors have first demonstrated that the triple domain CTLD3-CTLD4-CTLD5 of mouse is sufficient to bind sPLA2hGIB, and that the CTLD5 domain of mPLA2Rl is essential for the binding of sPLA2hGIB. Indeed, a series of deletion mutants (produced according to the protocol of Example 1) allowed to demonstrate that the CTLD3-4-5 domains of mPLA2Rl contain the hGIB binding site and are sufficient to bind sPLA2hGIB with high affinity (~1 nM), as shown in the left diagram of Fig. IB.

Example 3: Demonstration that a sPLA2hGIB-binding molecule comprising human CTLD3- CTLD4 domains and a mouse CTLD5 domain, bind to sPLA2hGIB

The inventors have also demonstrated that a sPLA2hGIB-binding molecule comprising a human CTLD3, a human CTLD4, and a mouse CTLD5 also comprise the full binding domain for sPLA2hGIB. A series of chimeras between mouse and human PLA2R1 (produced according to the protocol of Example 1) showed that the combination of mouse CTLD5 domain with CTLD3-CTLD4 domains of hPLA2Rl (expressed as a hCTLD3-hCTLD4-mCTLD5 chimera), allows to bind sPLA2hGIB with high affinity (~1 nM) (see the right diagram of Fig. IB).

Example 4: Production of modified CTLD5 domains of mouse PLA2R1

In this example, multiple modified mouse CTLD5 domains of PLA2R1 are generated according to the protocol of Example 1. The most interesting modified mouse CTLD5 domains selected by the inventors are described in details in the specification as chimeric CTLD5 domains having any of the following amino acid sequences: SEQ ID NO: 10 to 20 or 28 to 38.

Proteins comprising such a sequence selected from any one of SEQ ID NO: 10 to 20 or 28 to 38 thus represents potent sPLA2hGIB-binding molecules for use in the present invention.

Example 5: Production of modified CTLD5 domains of human PLA2R1

In this example, multiple modified human CTLD5 domains of PLA2R1 are produced according to the protocol of Example 1. The most interesting modified human CTLD5 domains selected by the inventors are described in details in the specification as chimeric CTLD5 domains having any of the following amino acid sequences: SEQ ID NO: 21 to 27 or 39 to 45.

Proteins comprising such a sequence selected from any one of SEQ ID NO: 21 to 27 or 39 to 45 thus represents potent sPLA2hGIB-binding molecules for use in the present invention. Example 6: Production and characterization of Proteinl and Protein3

6.1. Generation of chimeric Proteins 1 and 3

This example discloses the generation and properties of particular constructs suitable for therapeutic applications in humans: Proteinl (SEQ ID NO: 1) and Protein3 (SEQ ID NO: 3), as shown in Figure 3A. These proteins are produced according to the protocol as described in Example 1. Protein3 has an affinity for PLA2hGIB similar to mPLA2Rl (~1 nM) and is highly humanized (93.8% identity with CTLD3-4-5 domains of hPLA2Rl). More specifically, the CTLD5 domain of Proteins 1 and 3 is 81.9% identical to the CTLD5 domain of hPLA2Rl.

Protein3 includes hCTLD3 (AA 507-648 of SEQ ID NO: 46 comprising a CTLD3-linker from AA 507 to AA 512) and hCTLD4 (AA 649-801 of SEQ ID NO: 46 comprising a CTLD4-linker from AA 649 to AA 661) of hPLA2Rl, followed by the mouse CTLD5 domain (AA 802-942 of SEQ ID NO: 47 comprising a CTLD5-linker from AA 802 to AA 809) of which two parts of the "long loop" region (AA 878-892 and 901-915, as well as the beta-4 strand (AA 926-933) have been replaced by human sequences (Fig. 3A and 3C). Protein3 also comprises AA 943 to 956 of mouse PLA2R1.

Protein3 construction was expressed in COS cells from the vector pcDNA3.1Z-. The construction includes the signal peptide of sPLA2hGIIA, a 6xHIS tag and 3xFlag tag at the N-terminal end, and a HA tag at the C-terminal end (Fig. 4A). The inhibition properties of Protein3 on the enzymatic activity of sPLAhGIB are shown in Fig.5.

The results presented confirm that the CTLD5 domain of PLA2R1 is essential for the binding of sPLA2 and that the triple domain CTLD3-4-5 is the full binding domain for sPLA2hGIB. In addition, the results show that the human sequence can be murinized and/or the murine sequence humanized to generate molecules with improved binding properties. As an example, the presence of three short regions (i.e.: CTLD5-linker, alphal and alphalCl) of CTLD5 from mPLA2Rl in combination with LLR1, LLR2 and beta 4 regions from hPLA2Rl, is sufficient to confer high affinity and specificity to sPLA2hGIB (Fig. IB and Fig. 5).

6.2. Binding properties

To measure the affinity of Protein3 for sPLA2hGIB, the inventors have used an AlphaLISA^® test as described above. In this test, different sPLA2 can be introduced, which will compete with the measured signal.

The affinity of Protein3 is high for human sPLA2hGIB (~1 nM) as shown in table 1 below, but low for other sPLA2s such as sPLA2shGIIA or sPLA2hGX (data not shown). In addition, Protein3 also has a high affinity for macaque SPLA2GIB of around 1 nM (see Table 1) and a decreased affinity for mouse SPLA2GIB. Accordingly, Protein3 has a unique binding profile (as shown in Table 1).

Table 1: Binding properties of Protein3. The relative affinity of different SPLA2GIB molecules to a soluble form of mPLA2Rl and Protein3 was measured by the AlphaLISA^® test. In this assay, different SPLA2GIB molecules compete with the binding of sPLA2hGIIF and a PLA2R1 receptor (the whole extracellular region of mPLA2Rl or the Protein3, both HA-tagged).

6.3. Inhibition of hGIB enzymatic activity

Inhibition of enzymatic activity of sPLA2hGIB have been characterized with an enzymatic activity assay previously described (Rouault et al., 2007). Briefly, partially purified chimeric soluble forms were preincubated with sPLA2 for 15 minutes at room temperature in a final volume of 100 pL of enzymatic activity assay buffer [0.1 M Tris (pH 8.0), 10 mM CaCI2, and 0.1% bovine serum albumin]. Residual enzymatic activity was then measured at room temperature for 1 hour by addition of 40000 dpm of [³H] Oleate-radiolabeled E. Coli membranes in 200 pL of enzymatic activity assay buffer. Reactions were stopped by addition of 300 pL of stop buffer [0.1M EDTA (pH 8.0) and 0.1% fatty acid free bovine serum albumin]. Mixtures were centrifuged at 10,000g for 5 min, and the supernatants containing released [³H]oleate were counted.

To determine whether Protein3 inhibits the enzymatic activity of sPLA2hGIB, this latter was produced in larger amounts from COS cells and partially purified using HIS tag beads (Fig. 4B).

Protein3 (partially purified fraction) was sufficient to inhibit the sPLA2hGIB enzymatic activity in a manner similar to recombinant pure soluble mPLA2Rl (Fig. 5).

All of these experiments show that constructs of the invention, such as chimeric PLA2R1 receptors are potent sPLA2hGIB inhibitors and thus effective therapeutic agents. Example 7: Production and characterization of Protein2 and Protein4

Proteins 2 and 4 are chimeric PLA2R1 comprising the amino acid sequence of SEQ ID NO: 2 or 4, respectively, as shown in Figure 3A. These proteins are produced according to the protocol as described in Examplel. Proteins 2 and 4 are the most humanized constructions that bind to hGIB (97.56% identity with domains CTLD3-4-5 of hPLA2Rl, 92.95% identity with CTLD5 alone).

Protein4 includes domains CTLD3 (AA 507-648 comprising a CTLD3-linker from AA 507 to AA 512), CTLD4 (AA 649-801 comprising a CTLD4-linker from AA 649 to AA 661) and CTLD5 (AA 802- 942 comprising a CTLD5-linker from AA 802 to AA 809) of hPLA2Rl, of which the CTLD5-linker (AA 802-809) and two parts of the region located on both sides of the alpha-helix 1 of CTLD5 (AA 829-835 and 841-847) have been murinized (Fig. 3A and 3C). Protein4 also comprises AA 943 to

957 of human PLA2R1.

Protein4 was expressed in COS cells from the vector pcDNA3.1Z-. The construction includes the signal peptide of sPLA2hGIIA, a 6xH IS tag and 3xFlag tag at the N-terminal end, and a HA tag at the C-terminal end (Fig. 4A). The inhibition properties of Protein4 on the enzymatic activity of sPLAhGIB, were confirmed by the experimental data.

These results further confirm that the CTLD5 domain of mPLA2Rl is essential for the binding of sPLA2 and that the triple domain CTLD3-4-5 is the full binding domain for sPLA2hGIB. These results also confirm that the transfer of three specific regions of CTLD5 from mPLA2Rl to hPLA2Rl is sufficient to confer high affinity to sPLA2hGIB (Fig. IB). For instance, the transfer of the "CTLD5-linker" located between the CTLD4 and CTLD5, and two regions of 6-7 amino acids, located on both sides of the alpha-helix 1 of CTLD5, i.e., "alpha 1 region and "alpha 1C1" region can provide improved binding properties.

Proteins 2 and 4 thus also represent potent sPLA2hGIB inhibitors suitable for use as medicaments. SEQUENCE OF PROTEINS

SEQ ID NO: 1 Proteinl

VLSDAESGCQEGWERHGGFCYKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKDSYFWIA

LQDQNDTGEYTWKPVGQKPEPVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKAMSLCKQ

PVENQEKAEYEERWPFHPCYLDWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASFAHIEEEN

FVNELLHSKFNWTEERQFWIGFNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKANKTLLPL

HCGSKREWICKIPRDVRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQ

EFIHSKIKGLTKYGVKWWIGLQEERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGSE

ECSVSMPSICKRVKIWVIEKEKPPTQPGT

SEQ ID NO: 2 Protein2

VLSDAESGCQEGWERHGGFCYKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKDSYFWIA

LQDQNDTGEYTWKPVGQKPEPVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKAMSLCKQ

PVENQEKAEYEERWPFHPCYLDWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASFAHIEEEN

FVNELLHSKFNWTEERQFWIGFNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKANKTLLPL

HCGSKREWICKIPRDVRPKFPDWYQYDVPWLFYQDAEYLFHTHPAEWATFEFVCGWLRSDFLTIHSAHEQ

EFIHSKIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSE

ECSVSMPSICKRKKVWLIEKKKDTPKQHGT

SEQ ID NO: 3 Protein3

MKTLLLLAVIMIFGLLQAHGNHHHHHHDYKDHDGDYKDHDIDYKDDDDKVLSDAESGCQEGWERHGGFC

YKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKDSYFWIALQDQNDTGEYTWKPVGQKPE

PVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKAMSLCKQPVENQEKAEYEERWPFHPCYL

DWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASFAHIEEENFVNELLHSKFNWTEERQFWIG

FNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKANKTLLPLHCGSKREWICKIPRDVRPKFPD

WYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHSKIKGLTKYGVKWWIGLQ

EERANDEFRWRDGTPVIFQNWDTGRERTVNNQSQRCVFISSITGLWGSEECSVSMPSICKRVKIWVIEKEK

PPTQPGTYPYDVPDYA

SEQ ID NO: 4 Protein4

MKTLLLLAVIMIFGLLQAHGNHHHHHHDYKDHDGDYKDHDIDYKDDDDKVLSDAESGCQEGWERHGGFC

YKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKDSYFWIALQDQNDTGEYTWKPVGQKPE

PVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKAMSLCKQPVENQEKAEYEERWPFHPCYL

DWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASFAHIEEENFVNELLHSKFNWTEERQFWIG

FNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKANKTLLPLHCGSKREWICKIPRDVRPKFPD

WYQYDVPWLFYQDAEYLFHTHPAEWATFEFVCGWLRSDFLTIHSAHEQEFIHSKIKALSKYGASWWIGLQE

ERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEECSVSMPSICKRKKVWLIEKKKD

TPKQHGTYPYDVPDYA

SEQ ID NO: 5:

VLSDAESGCQEGWERHGGFCYKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKDSYFWIA

LQDQNDTGEYTWKPVGQKPEPVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKAMSLCKQ

PVENQEKAEYEERWPFHPCYLDWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASFAHIEEEN

FVNELLHSKFNWTEERQFWIGFNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKANKTLLPL

HCGSKREWICKIPRDVKPKIPFWYQYDVPWLFYQDAEYLFHTFASEWLNFEFVCSWLHSDLLTIHSAHEQEF

IHSKIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGLWGSEEC

SVSMPSICKRKKV

SEQ ID NO: 6 VPADEQSRCPAGWERHGRFCYKIDTVLRSFEEASSGYYCSPALLTITSRFEQAFITSLISSVAEKDSYFWIALQD QNNTGEYTWKTVGQREPVQYTYWNTRQPSNRGGCVVVRGGSSLGRWEVKDCSDFKAMSLCKTPVKIWE KTELEERWPFHPCYMDWESATGLASCFKVFHSEKVLMKRSWREAEAFCEEFGAHLASFAHIEEENFVNELL HSKFNWTQERQFWIGFNRRNPLNAGSWAWSDGSPVVSSFLDNAYFEEDAKNCAVYKANKTLLPSNCASK HEWICRIPRDVRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFLTIYSAQEQEFIHSKI KGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDKGREERVDSQRKRCVFISSITGLWGTESCSVPL PSICKRVKI

SEQ ID NO: 46 human PLA2R1

MLLSPSLLLLLLLGAPRGCAEGVAAALTPERLLEWQDKGIFVIQSESLKKCIQAGKSVLTLENCKQANKHMLW KWVSNHGLFNIGGSGCLGLNFSAPEQPLSLYECDSTLVSLRWRCNRKMITGPLQYSVQVAHDNTVVASRKY IHKWISYGSGGGDICEYLHKDLHTIKGNTHGMPCMFPFQYNHQWHHECTREGREDDLLWCATTSRYERDE KWGFCPDPTSAEVGCDTIWEKDLNSHICYQFNLLSSLSWSEAHSSCQMQGGTLLSITDETEENFIREHMSSK TVEVWVGLNQLDEDAGWQWSDGTPLNYLNWSPEVNFEPFVEDHCGTFSSFMPSAWRSRDCESTLPYICK KYLNHIDHEIVEKDAWKYYATHCEPGWNPYNRNCYKLQKEEKTWHEALRSCQADNSALIDITSLAEVEFLVT LLGDENASETWIGLSSNKIPVSFEWSNDSSVIFTNWHTLEPHIFPNRSQLCVSAEQSEGHWKVKNCEERLFYI CKKAGHVLSDAESGCQEGWERHGGFCYKIDTVLRSFDQASSGYYCPPALVTITNRFEQAFITSLISSVVKMKD SYFWIALQDQNDTGEYTWKPVGQKPEPVQYTHWNTHQPRYSGGCVAMRGRHPLGRWEVKHCRHFKA MSLCKQPVENQEKAEYEERWPFHPCYLDWESEPGLASCFKVFHSEKVLMKRTWREAEAFCEEFGAHLASF AHIEEENFVNELLHSKFNWTEERQFWIGFNKRNPLNAGSWEWSDRTPVVSSFLDNTYFGEDARNCAVYKA NKTLLPLHCGSKREWICKIPRDVKPKIPFWYQYDVPWLFYQDAEYLFHTFASEWLNFEFVCSWLHSDLLTIHS AHEQEFIHSKIKALSKYGASWWIGLQEERANDEFRWRDGTPVIYQNWDTGRERTVNNQSQRCGFISSITGL WGSEECSVSMPSICKRKKVWLIEKKKDTPKQHGTCPKGWLYFNYKCLLLNIPKDPSSWKNWTHAQHFCAE EGGTLVAIESEVEQAFITMNLFGQTTSVWIGLQNDDYETWLNGKPVVYSNWSPFDIINIPSHNTTEVQKHIP LCALLSSNPNFHFTGKWYFEDCGKEGYGFVCEKMQDTSGHGVNTSDMYPMPNTLEYGNRTYKIINANMT WYAAIKTCLMHKAQLVSITDQYHQSFLTVVLNRLGYAHWIGLFTTDNGLNFDWSDGTKSSFTFWKDEESSL LGDCVFADSNGRWHSTACESFLQGAICHVPPETRQSEHPELCSETSIPWIKFKSNCYSFSTVLDSMSFEAAHE FCKKEGSNLLTIKDEAENAFLLEELFAFGSSVQMVWLNAQFDGNNETIKWFDGTPTDQSNWGIRKPDTDYF KPHHCVALRIPEGLWQLSPCQEKKGFICKMEADIHTAEALPEKGPSHSIIPLAVVLTLIVIVAICTLSFCIYKHNG GFFRRLAGFRNPYYPATNFSTVYLEENILISDLEKSDQ SEQ ID NO: 47 mouse PLA2R1

MVQWLAMLQLLWLQQLLLLGIHQGIAQDLTHIQEPSLEWRDKGIFIIQSESLKTCIQAGKSVLTLENCKQPN EHMLWKWVSDDHLFNVGGSGCLGLNISALEQPLKLYECDSTLISLRWHCDRKMIEGPLQYKVQVKSDNTV VARKQIHRWIAYTSSGGDICEHPSRDLYTLKGNAHGMPCVFPFQFKGHWHHDCIREGQKEHLLWCATTSR YEEDEKWGFCPDPTSMKVFCDATWQRNGSSRICYQFNLLSSLSWNQAHSSCLMQGGALLGIADEDEEDFI RKHLSKVVKEVWIGLNQLDEKAGWQWSDGTPLSYLNWSQEITPGPFVEHHCGTLEVVSAAWRSRDCESTL PYICKRDLNHTAQGILEKDSWKYHATHCDPDWTPFNRKCYKLKKDRKSWLGALHSCQSNDSVLMDVASLA EVEFLVSLLRDENASETWIGLSSNKIPVSFEWSSGSSVIFTNWYPLEPRILPNRRQLCVSAEESDGRWKVKDC KERLFYICKKAGQVPADEQSRCPAGWERHGRFCYKIDTVLRSFEEASSGYYCSPALLTITSRFEQAFITSLISSV AEKDSYFWIALQDQNNTGEYTWKTVGQREPVQYTYWNTRQPSNRGGCVVVRGGSSLGRWEVKDCSDFK AMSLCKTPVKIWEKTELEERWPFHPCYMDWESATGLASCFKVFHSEKVLMKRSWREAEAFCEEFGAHLAS FAHIEEENFVNELLHSKFNWTQERQFWIGFNRRNPLNAGSWAWSDGSPVVSSFLDNAYFEEDAKNCAVYK ANKTLLPSNCASKHEWICRIPRDVRPKFPDWYQYDAPWLFYQNAEYLFHTHPAEWATFEFVCGWLRSDFL TIYSAQEQEFIHSKIKGLTKYGVKWWIGLEEGGARDQIQWSNGSPVIFQNWDKGREERVDSQRKRCVFISSI TGLWGTESCSVPLPSICKRVKIWVIEKEKPPTQPGTCPKGWLYFNYKCFLVTIPKDPRELKTWTGAQEFCVAK GGTLVSIKSELEQAFITMNLFGQTTNVWIGLQSTNHEKWVNGKPLVYSNWSPSDIINIPSYNTTEFQKHIPLC ALMSSNPNFHFTGKWYFDDCGKEGYGFVCEKMQDTLEHHVNVSDTSAIPSTLEYGNRTYKIIRGNMTWYA AGKSCRMHRAELASIPDAFHQAFLTVLLSRLGHTHWIGLSTTDNGQTFDWSDGTKSPFTYWKDEESAFLGD CAFADTNGRWHSTACESFLQGAICHVVTETKAFEHPGLCSETSVPWIKFKGNCYSFSTVLDSRSFEDAHEFC KSEGSNLLAIRDAAENSFLLEELLAFGSSVQMVWLNAQFDNNNKTLRWFDGTPTEQSNWGLRKPDMDHL

KPHPCVVLRIPEGIWHFTPCEDKKGFICKMEAGIPAVTAQPEKGLSHSIVPVTVTLTLIIALGIFMLCFWIYKQK

SDIFQRLTGSRGSYYPTLNFSTAHLEENILISDLEKNTNDEEVRDAPATESKRGHKGRPICISP

REFERENCES

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Claims

1. A sPLA2hGIB-binding molecule, wherein said molecule comprises a modified C-type lectin-like domain 5 (CTLD5) of PLA2R1 receptor.

2. The binding molecule of claim 1, wherein said CTLD5 domain is a chimeric CTLD5 domain.

3. The binding molecule of claim 1 or 2, wherein said CTLD5 domain is a murine domain in which the long loop region 1 (LLR1) and/or long loop region 2 (LLR2) are humanized.

4. The binding molecule of any one of claims 1 to 3, wherein said CTLD5 domain is a murine domain in which the β4 region is humanized.

5. The binding molecule of claim 1 or 2, wherein said CTLD5 domain is a human domain in which the a 1 and/or α1C1 regions are murinized.

6. The binding molecule of any one of the preceding claims, which further comprises CTLD3 and/or CTLD4 domain(s).

7. The binding molecule of claim 6, which further comprises a CTLD5-linker located between CTLD4 and CTLD5 domains.

8. The binding molecule of any one of the preceding claims, which does not comprise a CTLD1 and/or CTLD2 and/or CTLD6 and/or CTLD7 and/or CTLD8 domain(s).

9. The binding molecule of any one of the preceding claims, which comprises:

- a murine CTLD5 domain, preferably with humanized LLR1 and/or LLR2 and/or β4,

- a murine CTLD5-linker, and

- human CTLD3 and CTLD4 domains.

10. The binding molecule of any one of claims 1 to 8, which comprises:

- a human CTLD5 domain, preferably with murinized α 1 and/or α1C1,

- a CTLD5-linker, preferably a murinized CTLD5-linker, and

- human CTLD3 and CTLD4 domains.

11. The binding molecule of any one of the preceding claims, which is soluble.

12. The binding molecule of any one of the preceding claims, comprising an amino acid sequence of any one of SEQ ID NOs: 1 to 4 or 10 to 45, or comprising, consisting, or consisting essentially of a sequence having at least 80%, 85%, 90%, or more sequence identity to any one of SEQ ID NOs: 1 to 6 or 10 to 45, over the entire length thereof.

13. The binding molecule of claim 12, which further comprises a signal peptide, a polyhistidine-tag, preferably comprising at least 6 histidine repeats, and a 3xFlag peptide at the N-terminal end, as well as an HA-tag at the C-terminal end.

14. The binding molecule of claim 13, wherein the signal peptide is the signal peptide of SPLA2 hGIIA (SEQ ID NO: 7).

15. A nucleic acid molecule encoding for a molecule according to any one of claims 1 to 14.

16. A vector comprising a nucleic acid of claim 15.

17. A host cell comprising a nucleic acid of claim 15 or a vector of claim 16.

18. The host cell of claim 17, wherein the host cell is a mammalian cell such as a COS cell.

19. A method of expressing a molecule, said method comprising:

(i) culturing the host cell of claim 17 or 18 under condition suitable for the expression of the nucleic acid, and (ii) recovering the encoded molecule.

20. A composition comprising a binding molecule according to any one of claims 1 to 14, and a pharmaceutically acceptable carrier.

21. A composition comprising a nucleic acid according to claim 15 and a pharmaceutically acceptable carrier.

22. The binding molecule according to any one of claims 1 to 14, for use to modulate, preferably stimulate an immune response in a subject in need thereof.

23. The binding molecule according to any one of claims 1 to 14, for use to induce CD4 T cells in a subject.

24. The binding molecule according to any one of claims 1 to 14, for use in treating an infectious disease, immune disorder, immunodeficiency or cancer in a subject in need thereof.