WO2020245663A1

WO2020245663A1 - Nanobody-based ns1 assay for the specific diagnosis of acute zika virus infection

Info

Publication number: WO2020245663A1
Application number: PCT/IB2020/000516
Authority: WO
Inventors: Pierre Jacques LAFAYE; Marie Flamand
Original assignee: Institut Pasteur
Priority date: 2019-06-01
Filing date: 2020-05-29
Publication date: 2020-12-10

Abstract

The invention described herein relates to single variable domain antibodies, heavy-chain antibodies and other polypeptides, kits, and compositions and methods of using the same in detection and diagnosis of ZIKA virus infection. In some embodiments, the invention provides the first antigen capture ELISA specific for ZIKV NS1 using VHH/nanobodies. In a particular embodiment, the invention provides anti-NSl VHH/nanobodies and a sandwich ELISA test that is performed, in one embodiment, by using an anti-NSl monoclonal antibody for the capture and ZIKV NS1 specific nanobodies of the invention for the detection step. This assay can be used with a broad range of cross-reactive anti-NSl MAb in combination with Zika-specific nanobodies such as those of the invention.

Description

NANOBODY-BASED NS1 ASSAY FOR THE SPECIFIC DIAGNOSIS OF ACUTE ZIKA

VIRUS INFECTION

Field of the Invention

The invention described herein relates to single variable domain antibodies, heavy-chain antibodies and other polypeptides, and compositions and methods of using the same in detection and diagnosis of ZIKA virus infection, including in the early diagnosis of a Zika virus infection (DO to D5-7), which is found to be possible with detection of Zika virus NS1.

Background

Zika virus (ZIKV) is an Aedes mosquito-borne flavivirus that emerged in Brazil in 2015 and then rapidly spread throughout the tropical and subtropical Americas. As of February 1, 2016, ZIKV had emerged in 30 countries and territories in South/Central America, with alarming reports of microcephaly cases among neonates in Brazil ¹.

Based on clinical criteria alone, ZIKV infection cannot be reliably distinguished from infections with other pathogens that cause an undifferentiated systemic febrile illness, including infections with two common arboviruses, dengue virus and chikungunya virus. Diagnostics tools are thus needed to identify patients infected with Zika virus. The choice of a diagnostic method depends on the period between onset of symptoms and sample collection.

From the onset of clinical symptoms (Day 0) until the fifth/seventh day of illness (D5-7), diagnosis of Flavivirus infection can be done by virus isolation on cell culture, which presents however the disadvantages of being time-consuming and high-expertise assays. Reverse transcription- polymerase chain reaction (RT-PCR) is commonly used in this period to detect the viral RNA, and many assays have been validated for ZIKV ².

For Dengue virus (DENV), the detection of viral NS1 antigen in the same DO to D5-7 sampling window has become the reference diagnostic assay over the past few years ' . The NS1 antigen has also been detected in patients infected with yellow fever or West Nile viruses, suggesting that NS1 secretion is a hallmark of flavivirus infections ⁷.

From D5, the diagnosis of flaviviruses is based on serological methods used to highlight the presence of IgM or IgG antibodies. Serological tests have the advantage of a larger window for sampling, ease to use and reduced costs, but the diagnostic can only be reliably obtained after complete resolution of the infection. Antibodies can be of particular interest to detect NS1 because of their exquisite binding specificity toward the antigen. The use of antibodies to detect ZIKV NS1 is however limited by high cross reactivity of antibodies between NS1 from different flaviviruses. While conventional immunoglobulins are heterotetramers composed of two heavy and two light chains (each comprising a variable region (VH and VL) and a constant region), with a molecular weight of about 150 KD, in camelids a significant proportion of serum antibodies are homodimeric IgGs with a molecular weight of about 80 kD. Their heavy chains contain three domains instead of four in conventional antibodies. The variable domain of these heavy-chain only antibodies is referred to as VHH (commercially known as nanobodies). Recombinant nanobodies (-12-14 kD in size) constitute intact antigen-binding domains and exhibit a broad antigen-binding repertoire. Since nanobodies are small and have high targeting precision they are ideal to specifically target conformation specific neoepitopes ⁸. They have been raised to target numerous viruses ^{9 10}.

Summary of the Invention

Prior to this invention, the detection of ZIKV NS1 using VHH/nanobodies remained to be demonstrated. According to this disclosure, an early diagnosis of a ZIKAV infection (DO to D5-7) can be possible with detection of ZIKV NS1. In one embodiment, the invention provides the first antigen capture ELISA specific for ZIKV NS1 using VHH/nanobodies. In one embodiment, the invention provides anti-NSl VHH/nanobodies and a sandwich/antigen capture ELISA test that is performed by using an anti-NSl monoclonal antibody for the capture and ZIKV NS1 specific nanobodies of the invention for the detection. In one embodiment, the invention provides anti-NSl VHH/nanobodies and a sandwich ELISA test that is performed by using an anti-NSl monoclonal antibody for the detection and ZIKV NS1 specific nanobodies of the invention for the capture. This assay can be used with a broad range of anti-NSl MAb in combination with Zika-specific nanobodies such as those of the invention. In one embodiment, the invention provides a companion diagnostic assay for the selection of a patient for specific treatment of a ZIKA virus infection. In one embodiment, the invention provides the use of VHH/nanobodies in serologic assays.

It is to be understood that the invention is not limited in its application to the details set forth in the following embodiments, claims, description and figures. The invention is capable of other embodiments and of being practiced or carried out in numerous other ways.

The following are some exemplary embodiments of the invention: 1. A single variable domain antibody comprising three complementarity-determining regions CDR1, CDR2, and CDR3, wherein the three CDRs comprise the following sets of sequences:

CDR1 (SGRTFSNY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISW, SEQ ID NO: 2), and CDR3 (AAGEV GAFY SD YDLYD Y, SEQ ID NO: 3); and/or

CDR1 (SGRTFSNY AMD Y AMG, SEQ ID NO: 1), CDR2 (ADSV, SEQ ID NO: 4), and CDR3 (AAGEV GAFY SD YDLYD Y, SEQ ID NO: 3)

2. A single variable domain antibody of the invention comprising from the N-terminus to the C- Terminus the amino acid sequence SGRTFSNY AMD Y AMG (SEQ ID NO: 1), SGRTFSNY AMG (SEQ ID NO: 5), SGRTFYRNTMG (SEQ ID NO: 6), SGFTFSSYPMR (SEQ ID NO: 7), or SGRTFSAYAIG (SEQ ID NO: 8) (corresponding to CDR1), the amino acid sequence AAISWSGGSTYGADSV (SEQ ID NO: 9), AAISGGRTYTRYANSV (SEQ ID NO: 10), AAISWSGHSTYSADSV (SEQ ID NO: 11), SAITWSGNSTPYADSV (SEQ ID NO: 12), AAISWSGDSTYPADSV (SEQ ID NO: 13), SIINSDGSSTYYADSV (SEQ ID NO: 14), or AAISGGVVYTRYADFV (SEQ ID NO: 15) (corresponding to CDR2), and the amino acid sequence AAGEVGAFY SDYDLYDY (SEQ ID NO: 3), SASQVGSGLAPTTRDRYAV (SEQ ID NO: 16), A AGP YMT A APRT S S S YKY (SEQ ID NO: 17), ARGRGV SDPGGMD Y (SEQ ID NO: 18), or AAGQVGSGLAPTTRDRYVV (SEQ ID NO: 19) (corresponding to CDR3).

3. A single variable domain antibody comprising three complementarity-determining regions CDR1, CDR2, and CDR3, wherein the three CDRs comprise the following sets of sequences: CDR1 (SGRTFSNY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISWSGGSTYGADSV, SEQ ID NO: 9), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

CDR1 (SGRTFSNY AMG, SEQ ID NO: 5), CDR2 (AAISGGRTYTRYANSV, SEQ ID NO: 10), and CDR3 (SASQVGSGLAPTTRDRYAV, SEQ ID NO: 16);

CDR1 ( SGRTFS NY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISWSGHSTYSADSV, SEQ ID NO: 11), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

CDR1 (SGRTFYRNTMG, SEQ ID NO: 6), CDR2 (SAITWSGNSTPYADSV, SEQ ID NO: 12), and CDR3 (AAGPYMTAAPRTSSSYKY, SEQ ID NO: 17);

CDR1 ( SGRTFS NY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISWSGDSTYPADSV, SEQ ID NO: 13), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3); CDR1 (SGFTFS S YPMR, SEQ ID NO: 7), CDR2 (SIINSDGSSTYYADSV, SEQ ID NO: 14), and CDR3 (ARGRG V SDPGGMD Y, SEQ ID NO: 18); or

CDR1 (SGRTFSAYAIG, SEQ ID NO: 8), CDR2 (AAISGGVVYTRY ADFV, SEQ ID NO: 15), and CDR3 (AAGQVGSGLAPTTRDRYVV, SEQ ID NO: 19).

4. The single variable domain antibody according to any one of embodiments 1 through 3, wherein the antibody binds to the ZIKA Virus (ZIKV).

5. The single variable domain antibody according to any one of embodiments 1 through 4, wherein the antibody binds to the ZIKA NS1 protein from the ZIKV.

6. The single variable domain antibody according to any one of embodiments 1 through 5, wherein the antibody preferentially binds to NS1 protein from the ZIKV over NS1 from other flavivirus.

7. The single variable domain antibody according to embodiment 5, wherein the other flavivirus is one or more of DENV, WNV, YFV, Tick-borne encephalitis virus, and Japanese encephalitis virus.

8. The single variable domain antibody of any one of embodiments 1 through 7, wherein the antibody comprises the variable domain of the heavy-chain of a heavy-chain antibody (VHH) from a camelid, fish, or shark.

9. The single variable domain antibody of any one of embodiments 1 through 8, wherein the camelid is a camel, alpaca, or a llama.

10. The single variable domain antibody of any one of embodiments 1 through 9, wherein the antibody is conjugated to an agent.

11. The single variable domain antibody of any one of embodiments 1 through 10, wherein the agent is a detectable label.

12. The single variable domain antibody of any one of embodiments 1 through 11, wherein the detectable label comprises a peptide sequence (e.g., His-tag), an enzyme (such as horseradish peroxidase, alkaline peroxidase, glucose 6-phosphate dehydrogenase, beta-galactosidase, and luciferase, and the like), biotin, streptavidin, an acridinium compound, a radioisotope (such as 3H, 1251, 35S, 14C, 32P, and 33P), a positron emitter, a fluorophore, a chemiluminescent moiety (such as acridinium esters, thioesters, or sulfonamides; luminol, isoluminol, phenanthridinium esters, and the like), rhodamine, phycobiliproteins, R-phycoerythrin, quantum dots (e.g., zinc sulfide-capped cadmium selenide), a thermometric label, an immuno-polymerase chain reaction label, a nuclear magnetic resonance marker, a heavy metal, gold nanoparticles, colored latex beads, magnetic particles, carbon nanoparticles, selenium nanoparticles, silver nanoparticles, quantum dots, up converting phosphors, organic fluorophores, textile dyes, and liposomes.

13. The single variable domain antibody of any one of embodiments 1 through 10, wherein the agent is a solid surface or particule.

14. The single variable domain antibody of any one of embodiments 1 through 13, wherein the antibody is the antibody NSl-1, NSl-10, NS1-20, NS1-21, NS 1-22, NS 1-26, or NS1-31.

15. A heavy-chain antibody comprising a variable region (VHH), an hinge, and one or two constant regions (CH2 an CH3), wherein the variable region (VHH) comprises the sequence of the antibody of any one of embodiments 1 through 14.

16. The heavy-chain antibody of embodiment 15, wherein one or more of the constant regions is of the IgM, IgG, IgD, IgA, or IgE class.

17. The heavy-chain antibody of any one of embodiments 15 through 16, wherein one or more of the constant regions is of human origin.

18. A polypeptide comprising one or more of the following sequences:

QLQLVESGGGLVQTGGSLRLSCAASGRTFSNYAMDYAMGWFRQAPGKEREFVAAISWS GGSTYGADSVKGRFriSRDNAKNTVYLQMNSLKPEDTAVYYCAAGEVGAFYSDYDLYD YWGQGTQVTVSSEPKTPKPQP (SEQ ID NO: 20);

EVQLVESGGGLVQPGGSLRLSCAASGRTFSNYAMGWFRQAPEKEREFVAAISGGRTYTR YANSVKGRFTISRDNAKNTVYLQMNSLEPEDTAVYYCSASQVGSGLAPTTRDRYAVWG QGTQ VT V S SEPKTPKPQP (SEQ ID NO: 21);

EV QLVESGGGL V QTGGS LRLSC A ASGRTFS NY AMD Y AMG WFRQ APGEEREFV A AIS W S GHSTYSADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAGEVGAFYSDYDLYD YWGQGIQVTVSSEPKTPKPQP (SEQ ID NO: 22); QVQLVESGGGLVQAGGSLRLYCAASGRTFYRNTMGWFRQVAGKEREFVSAITWSGNST PYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAGPYMTAAPRTSSSYKYWG QGTQVTVSS (SEQ ID NO: 23);

EVQLVESGGGLVQTGGSLRLSCAASGRTFSNYAMDYAMGWFRQAPGKEREFVAAISWS GDSTYPADSVKGRFTISRDNAKNTVLLQMNSLKPEDTAVYYCAAGEVGAFYSDYDLYD YWGQGTQVTVSS (SEQ ID NO: 24);

QVQLVESGGGLVQPGGSLRLSCAASGFTFSSYPMRWVRQAPGKGLERVSIINSDGSSTYY ADSVKGRFTISRDNAKNTLYLQMNSLKPEDTGVYYCARGRGVSDPGGMDYRGKGTQV TVSS (SEQ ID NO: 25); and

DVQLIESGGGLVQVGDSLRLSCAASGRTFSAYAIGWFRQAPGKEREFVAAISGGVVYTR Y ADFVKGRFTI ARDN AKNL VSLQMN S LEPEDT A V YFC A AGQ V GS GLAPTTRDR Y V V WG QGTQVTVSS (SEQ ID NO: 26).

19. A polypeptide comprising a single variable domain antibody comprising from the N-terminus to the C-Terminus the amino acid sequence SGRTFSNYAMDYAMG (SEQ ID NO: 1), SGRTFSNYAMG (SEQ ID NO: 5), SGRTFYRNTMG (SEQ ID NO: 6), SGFTFSSYPMR (SEQ ID NO: 7), or SGRTFSAYAIG (SEQ ID NO: 8) (corresponding to CDR1), the amino acid sequence AAISWSGGSTYGADSV (SEQ ID NO: 9), AAISGGRTYTRYANSV (SEQ ID NO: 10), AAIS WSGHSTY S ADS V (SEQ ID NO: 11), SAITWSGNSTPYADSV (SEQ ID NO: 12), AAISWSGDSTYPADSV (SEQ ID NO: 13), SIINSDGSSTYYADSV (SEQ ID NO: 14), or AAISGGVVYTRYADFV (SEQ ID NO: 15) (corresponding to CDR2), and the amino acid sequence AAGEVGAFY SDYDLYDY (SEQ ID NO: 3), SASQVGSGLAPTTRDRYAV (SEQ ID NO: 16), A AGP YMT A APRT S S S YKY (SEQ ID NO: 17), ARGRGV SDPGGMD Y (SEQ ID NO: 18), or AAGQVGSGLAPTTRDRYVV (SEQ ID NO: 19) (corresponding to CDR3).

20. A polypeptide comprising an immunoglobulin variable domain comprising three complementarity-determining regions CDR1 , CDR2, and CDR3, wherein the three CDRs comprise the following sets of sequences:

CDR1 (SGRTFSNYAMDYAMG, SEQ ID NO: 1), CDR2 (AAISWSGGSTYGADSV, SEQ ID NO: 9), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3); CDR1 (SGRTFSNY AMG, SEQ ID NO: 5), CDR2 (AAISGGRTYTRYANSV, SEQ ID NO: 10), and CDR3 (SASQVGSGLAPTTRDRYAV, SEQ ID NO: 16);

CDR1 ( SGRTFS NY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISWSGDSTYPADSV, SEQ ID NO: 13), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

CDR1 (SGFTFS S YPMR, SEQ ID NO: 7), CDR2 (SIINSDGSSTYYADSV, SEQ ID NO: 14), and CDR3 (ARGRG V SDPGGMD Y, SEQ ID NO: 18); or

21. A nucleic acid encoding any one of the single variable domain antibodies, heavy chain antibodies, or other polypeptide of embodiments 1 through 20.

22. The nucleic acid of embodiment 21, wherein the nucleic acid encodes any one of the following sequences:

NSl-1

QLQLVESGGGLVQTGGSLRLSCAASGRTFSNYAMDYAMGWFRQAPGKEREFVAAISWS GGSTYGADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAGEVGAFYSDYDLYD YWGQGTQVTVSSEPKTPKPQP (SEQ ID NO: 20);

NSl-10

NS 1-20

EV QLVESGGGL V QTGGS LRLSC A ASGRTFS NY AMD Y AMG WFRQ APGEEREFV A AIS W S GHSTYSADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAGEVGAFYSDYDLYD YWGQGIQVTVSSEPKTPKPQP (SEQ ID NO: 22);

NS 1-21 QVQLVESGGGLVQAGGSLRLYCAASGRTFYRNTMGWFRQVAGKEREFVSAITWSGNST PYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAGPYMTAAPRTSSSYKYWG QGTQVTVSS (SEQ ID NO: 23);

NS 1-22

NS 1-26

NS1-31

23. The nucleic acid of embodiment 21, wherein the nucleic acid comprises any one of the following sequences:

>NS1-1

CAGTTGCAGCTCGTGGAGTCCGGGGGAGGATTGGTGCAGACTGGGGGCTCTCTGAG ACTCTCCTGTGCAGCCTCTGGACGCACCTTCAGTAACTATGCCATGGATTATGCCAT GGGCTGGTTCCGCCAGGCTCCAGGGAAGGAGCGTGAGTTTGTAGCAGCTATTAGCT GGAGTGGTGGTAGCACATACGGTGCAGACTCCGTGAAGGGCCGATTCACCATCTCC AGAGACAACGCCAAGAACACGGTGTATCTGCAAATGAACAGCCTGAAACCTGAGGA CACGGCCGTTTATTACTGTGCGGCCGGAGAAGTGGGGGCTTTCTATAGCGACTATGA CTTGTATGACTACTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCAGAACCCAAGA CACCAAAACCACAACCA (SEQ ID NO: 27);

>NS1-10

GAGGTGCAGCTGGTAGAGTCTGGGGGAGGATTGGTGCAGCCTGGGGGCTCTCTGAG ACTCTCCTGTGCCGCCTCTGGACGCACCTTCAGTAATTATGCCATGGGCTGGTTCCG CCAGGCTCCAGAAAAGGAGCGTGAGTTTGTAGCAGCTATTAGTGGGGGTCGTACTT ACACACGCTATGCGAACTCCGTGAAGGGCCGATTCACCATCTCCAGAGACAACGCC AAGAACACGGTGTATCTGCAAATGAACAGCCTGGAACCTGAGGACACGGCCGTTTA TTACTGTTCGGCGAGTCAGGTTGGGAGCGGACTAGCTCCTACTACACGTGATCGGTA TGCCGTCTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCAGAACCCAAGACACCAA AACCACAACCA (SEQ ID NO: 28);

>NSl-20

GAGGTGCAGCTGGTAGAGTCTGGGGGAGGATTGGTGCAGACTGGGGGCTCTCTGAG ACTCTCCTGTGCAGCCTCTGGACGCACCTTCAGTAACTATGCCATGGATTATGCCAT GGGCTGGTTCCGCCAGGCTCCAGGGGAGGAGCGTGAGTTTGTAGCAGCTATTAGCT GGAGTGGTCATAGCACATACTCTGCAGACTCCGTGAAGGGCCGATTCACCATCTCCA GAGACAACGCCAAGAACACGGTGTATCTGCAAATGAACAGCCTGAAACCTGAGGAC ACGGCCGTTTATTACTGTGCAGCCGGAGAAGTGGGGGCTTTCTATAGCGACTATGAC TTGTATGACTACTGGGGCCAGGGGATCCAGGTCACCGTCTCCTCAGAACCCAAGAC ACCAAAACCACAACCA (SEQ ID NO: 29);

>NS1-21

CAGGTGCAGCTCGTGGAGTCTGGGGGAGGATTGGTGCAGGCTGGGGGCTCTCTGAG ACTCTACTGTGCAGCCTCTGGACGCACCTTCTATAGAAATACCATGGGCTGGTTCCG CCAGGTTGCAGGGAAGGAGCGTGAGTTTGTGTCAGCGATTACCTGGAGTGGGAATA GCACACCCTATGCAGACTCTGTGAAGGGCCGATTCACCATCTCCAGAGATAACGCC AAGAACACGGTGTACCTGCAAATGAACAGCCTGAAACCTGAGGACACGGCCGTTTA TTACTGTGCAGCGGGGCCCTATATGACGGCCGCACCCCGGACCTCCAGTTCGTATAA GTACTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 30);

>NSl-22

GAGGTGCAGCTGGTAGAGTCTGGGGGAGGATTGGTGCAGACTGGGGGCTCTCTGAG ACTCTCCTGTGCAGCCTCTGGACGCACCTTCAGTAACTATGCCATGGATTATGCCAT GGGCTGGTTCCGCCAGGCTCCAGGGAAGGAGCGTGAGTTTGTAGCAGCTATTAGCT GGAGTGGTGATAGCACATACCCTGCAGACTCCGTGAAGGGCCGATTCACCATCTCC AGAGACAACGCCAAGAACACGGTGCTTCTGCAAATGAACAGCCTGAAACCTGAGGA CACGGCCGTTTATTACTGTGCAGCCGGAGAAGTGGGGGCTTTCTATAGCGACTATGA CTTGTATGACTACTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 31); >NSl-26 CAGGTGCAGCTCGTGGAGTCAGGGGGAGGCTTGGTGCAACCTGGGGGGTCTCTGAG ACTCTCCTGTGCAGCCTCTGGATTCACCTTTAGTAGCTATCCTATGAGATGGGTCCGC CAGGCTCCAGGAAAGGGGCTCGAGCGGGTCTCAATTATTAATAGTGATGGTAGTAG CACATACTATGCAGACTCCGTGAAGGGCCGGTTCACCATCTCCAGAGACAACGCCA AGAACACGCTGTATCTGCAAATGAACAGCCTGAAACCTGAGGACACGGGCGTGTAT TACTGTGCAAGAGGGCGAGGAGTAAGTGATCCGGGGGGCATGGACTATCGGGGCAA AGGGACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 32); and

>NS1-31

GATGTGCAGCTGATAGAGTCTGGGGGAGGATTGGTGCAGGTTGGAGACTCTCTGAG ACTCTCCTGTGCCGCCTCTGGACGCACCTTCAGTGCTTATGCCATAGGCTGGTTCCGC CAGGCTCCAGGGAAGGAGCGTGAGTTTGTAGCAGCTATTAGTGGGGGTGTTGTTTAT ACACGCTATGCAGACTTCGTGAAGGGCCGATTCACCATCGCCAGAGACAACGCCAA GAACTTGGTGTCCCTGCAAATGAACAGCCTGGAACCTGAGGACACGGCCGTTTATTT TTGTGCAGCAGGTCAGGTTGGGAGCGGACTAGCTCCTACTACACGTGATCGGTATGT GGTCTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 33).

24. A genetic construct comprising a nucleic acid according to any one of embodiments 21 through 23.

25. The genetic construct according to embodiment 24, wherein the genetic construct is a vector.

26. The vector according to embodiment 25, wherein the vector is an expression vector and wherein the nucleic acid is in combination with control sequences to direct its expression.

27. The vector according to embodiment 26, wherein the vector is a bacterial vector or an eukaryotic expression vector.

28. A recombinant host cell comprising a nucleic acid encoding one or more single variable domain antibodies, heavy chain antibodies, or other polypeptide according to any one of embodiments 1 thrrough 20, or a vector comprising a nucleic acid encoding one or more single variable domain antibodies, heavy chain antibodies, or other polypeptide according to any one of embodiments 1 through 20.

29. A composition comprising a single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20 and a pharmaceutically acceptable carrier. 30. A method of detecting ZIKV NS1 protein in a biological sample comprising (i) contacting the biological sample with an anti-NSl single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 21 through 23 under conditions permissive for binding of the anti-NSl antibody, heavy-chain antibody, or other polypeptide to ZIKV NS1 protein in the sample and (ii) detecting whether a complex is formed between the anti-NSl antibody, heavy-chain antibody, or other polypeptide and the ZIKV NS1 protein in the biological sample, wherein detection of the formation of the complex indicates the presence of ZIKV NS1 protein in the sample.

31. The method according to embodiment 30, wherein the presence of ZIKV NS1 in a sample from a subject indicates that the subject is or has been infected with ZIKV or is diagnostic of ZIKV infection.

32. The method according to any one of embodiments 30 through 31, wherein detection of the presence of ZIKV NS1 in the sample is done by an in vitro immunoassay.

33. The method according to embodiment 32, wherein the immunoassay is by Western Blotting, immunoprecipitation, immunocytochemistry, immunohistochemistry, immunoelectron microscopy, radioimmunoassay, optical immunoassay, Enzyme-Linked ImmunoSpot (ELISPOT) assay, 2D gel electrophoresis, digital enzyme-linked immunosorbent assay (ELISA), or analog ELISA, such as enzyme multiplied immunoassay technique (EMIT), enzyme-linked immunosorbent assay (ELISA), IgM antibody capture ELISA (MAC ELISA), and microparticle enzyme immunoassay (MEIA); capillary electrophoresis immunoassays (CEIA); radioimmunoassays (RIA); immunoradiometric assays (IRMA); fluorescence polarization immunoassays (FPIA); and chemiluminescence assays (CL).

34. The method according to any one of embodiments 32 through 33, wherein the immunoassay is an antigen capture/sandwich immunoassay with a capture anti-NSl antibody and a detection anti-NSl antibody.

35. The method according to embodiment 34, wherein either the capture antibody, the detection antibody, or both antibodies are single variable domain antibodies.

36. The method according to any one of embodiments 34 through 35, wherein the capture antibody is a monoclonal anti-NSl antibody. 37. The method according to any one of embodiments 34 through 36, wherein the capture antibody is a single variable domain anti-NSl antibody.

38. The method according to any one of embodiments 34 through 37, wherein the detection antibody is a monoclonal anti-NSl antibody.

39. The method according to any one of embodiments 34 through 38, wherein the detection antibody is a single variable domain anti-NSl antibody.

40. The method according to any one of embodiments 30 through 39, wherein at least one of the antibodies preferentially binds to NS1 protein from the ZIKA Virus (ZIKV) over NS1 from other flavivirus, as measured by at least one assay.

41. The method according to embodiment 40, wherein the other flavivirus is one or more of DENV, WNV, YFV, Tick-borne encephalitis virus, and Japanese encephalitis virus.

42. The method according to any one of embodiments 30 through 41, wherein the method is quantitative.

43. The method according to any one of embodiments 30 through 42, wherein the biological sample comprises blood, plasma, serum, saliva, cerebrospinal fluid, a tissue biopsy, cells isolated from a subject being tested (e.g., immune cells, cells isolated from cheeks or gums), cells grown and/or processed in vitro , aqueous humour, vitreous humour, bile, breast milk, endolymph, perilymph gastric juice, mucus, peritoneal fluid, pleural fluid, sebum, semen, sweat, tears, vaginal secretion, vomit, or urine.

44. The method according to any one of embodiments 30 through 43, wherein the single variable domain antibody, heavy-chain antibody, or other polypeptide is an antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20.

45. The method according to any one of embodiments 30 through 44, wherein the antibody is the NS 1-21 antibody.

46. The method according to any one of embodiments 30 through 45, wherein the antibody or polypeptide is conjugated to a His-tag or a Streptavidin tag.

47. The method according to any one of embodiments 30 through 46, wherein the antibody or polypeptide is any one of the antibodies or polypeptides of the above embodiments. 48. The method according to any one of embodiments 30 through 47, wherein the single variable domain antibody, heavy chain antibody, or other polypeptide is used in combination with an anti- NS1 antibody selected from mAbs mAh 17A12 and mAh 6B8.

49. A kit for detecting ZIKV NS1 protein in a sample comprising a single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20.

50. The kit of embodiment 49, wherein the kit is a diagnostic kit.

51. The kit according to any one of embodiments 49 through 50, wherein the single variable domain antibody, heavy chain antibody, or other polypeptide is immobilized on a support (e.g., an insoluble substrate, such as a plate or slide made of glass, plastic or metal, a polymer-coated bead, a tube, or a ceramic or metal chip) that comprises immobilized (or otherwise deposited) one or more of the antibodies or polypeptides of the invention.

52. The kit according to any one of embodiments 49 through 51, wherein the single variable domain antibodies, heavy chain antibodies, or other polypeptide is conjugated to a bead.

53. The kit according to any one of embodiments 49 through 52, wherein the single variable domain antibodies, heavy chain antibodies, or other polypeptide is labeled with a His-tag/agent or with a streptavidin-tag/agent.

54. The use of a single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20 for the preparation of a reagent to detect ZIKV NS1 protein in vitro or in vivo.

55. The use of a single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20 for the preparation of a reagent to diagnose ZIKV infection in vitro or in vivo.

56. An article of manufacture (kit) for diagnostic use, comprising packaging material and a container comprising one or more of the single variable domain antibodies, heavy-chain antibodies or other polypeptides of any one of embodiments 1 through 20.

57. The single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20, for use in the detection of ZIKV NS1 protein. 58. A nucleic acid according to any one of embodiments 21 through 23, for use in the manufacture of a reagent to use in the detection or diagnosis of ZIKV infection, preferably by ZIKV NS1 protein detection.

59. A single variable domain antibody, heavy-chain antibody, or other polypeptide according to any one of embodiments 1 through 20, for use in the manufacture of a reagent to use in the detection or diagnosis of ZIKV infection, preferably by ZIKV NS1 detection.

60. A companion diagnostic assay for the selection of a patient for specific treatment of a ZIKA virus infection, wherein the assay comprises:

(i) performing the method according to embodiments 30 through 48 to detect ZIKV in a biological sample of the patient before treatment, and

(ii) deciding whether the result of the assay is indicative for the treatment of a ZIKA virus infection,

wherein the result of the assay is indicative for the treatment of a ZIKA virus infection when a complex is formed between the anti-NSl antibody, heavy-chain antibody, or other polypeptide described herein and the ZIKV NS1 protein in the biological sample.

61. Use of a single variable domain antibody according to embodiments 1 to 14, a heavy-chain antibody according to embodiments 15 through 17 or a peptide according to embodiments 18 through 20 in an in vitro companion diagnostic assay for the selection of a patient for specific treatment of a ZIKA virus infection.

62. Use of a single variable domain antibody according to embodiments 1 to 14, a heavy-chain antibody according to embodiments 15 through 17 or a peptide according to embodiments 18 through 20 to calibrate an in vitro serologic test.

63. Use of a single variable domain antibody according to embodiments 1 to 14, a heavy-chain antibody according to embodiments 15 through 17 or a peptide according to embodiments 18 through 20 as a positive control reagent in an in vitro serologic test.

64. A product or process substantially as hereinbefore described with reference to any one of the Examples and to any one of the accompanying drawings. Legends of the figures

Figure 1 shows the nucleotide sequences of anti-ZIKV NS1 Nanobodies used in the Examples. Figure 2 shows the deduced amino acid sequences of anti-ZIKV NS1 nanobodies. CDR1, CDR2 and CDR3 are underlined.

Figure 3 exemplifies a binding analysis of nanobobodies (Nb) against ZIKV NS1 and DENV NS1 Strep-tagged NS1 proteins. Purified protein preparations were coated on a Streptactin microtiter plate. After washing, VHHs were incubated for 1 hour at 37°C. VHH detections were performed using an anti-His Tag mAb.

Figure 4 exemplifies reactivity of nanobodies (Nb) to the Strep-tagged ZIKV NS1 in the antigen capture ELISA. mAb 17A12 (A) and mAb 6B8 (B) were used as capture antibodies.

Figure 5 exemplifies the equilibrium K_d of Nanobodies for ZIKV NS1 protein. K_d of antigen/Nb interactions were determined under equilibrium conditions as described in “Material and Methods”.

Detailed Description

The invention relates to single variable domain antibody, heavy-chain antibody, or other polypeptide, uses thereof, compositions, assays and methods for the detection of ZIKV NS1 protein. Preferred embodiments, even if not explicitly stated, are those directed to one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

Some aspects of the invention relate to single variable domain antibodies. Indeed, in general, single variable domain antibodies refer to the smallest known fragments of an immunoglobulin that is still capable of binding an antigen. In other words, single variable domain antibodies are also referred to as heavy-chain variable domain antibodies and are immunoglobulin variable domains that can form a functional antigen binding site without interaction with a VL domain. They can be said to be a kind of antibody fragments consisting of a single monomeric variable antibody domain and lacking the light chain and CH domain of the heavy chain in conventional Fab region. Single domain antibodies, dAbs, VHH (from camelids), VNAR (from cartilaginous fishes), sdAb, and nanobodies, are all sources of single variable domain antibodies within the scope of the invention. Some single domain antibodies can be engineered from the VHH domain of heavy-chain antibody identified in camelids (e.g. dromedaries, camels, llamas, and alpacas). The VNAR domain of cartilaginous fishes (e.g. shark) heavy-chain antibody (known as IgNAR, immunoglobulin new antigen receptor) is another well-established source for single domain antibody development. Another approach is to split the dimeric variable domains from normal IgG of humans or mice into monomers by camelizing a few critical residues. The single variable domain antibody can be isolated, recombinant or synthetic. In a preferred embodiment, the single variable domain antibody is a Nanobody, a term that applies to commercialized single variable domain antibodies originally coined by Ablynx, most of which have sequences that are derived from VHHs of llamas and other camelids, but are then produced entirely recombinantly. Nanobody or Nanobodies are registered trademarks of Ablynx N.V. and thus may also be referred to as Nanobody™ and/or Nanobodies™). Generally, single variable domain antibody will have an amino acid sequence comprising 4 framework regions (FR1 to FR4) and 3 complementarity determining regions (CDR1 to CDR3), preferably according to the following formula: FR1-CDR1-FR2-CDR2-FR3-CDR3-FR4. In the present application, the amino acid residues/positions in an immunoglobulin heavy-chain variable domain will be indicated with the numbering according to IMGT (http://www.imgt.org/).

The invention provides for single variable domain antibodies against the ZIKA (ZIKV) virus. In one embodiment, the ZIKV is of the East Africa, West Africa, or Asian strain. In a preferred embodiment, the ZIKV is of the Asian strain.

In a preferred embodiment, the single variable domain antibodies are antibodies against ZIKV NS1 protein. In one embodiment, the NS1 protein is specified by the H/PF/2013 strain of ZIKV (GeneBank access number KJ776791). In one embodiment, recombinant Zika NS1 can be produced as previously described for dengue NS1 ⁿ.

In one embodiment, the single variable domain antibodies are VHHs. In a preferred embodiment, the single variable domain antibodies are referred to as nanobodies. In one embodiment, the VHH is isolated from, or derived from a VHH of a camelid. In one embodiment, the camelid is an Alpaca. In another embodiment, the camelid is a camel or a llama. In one embodiment, the VHH is isolated or derived from a VHH of a fish or a shark. In one embodiment, the single variable domain antibodies are humanized VHHs. In another embodiment, the single variable domain antibodies are camelized VHHs.

In one embodiment, the nanobodies preferentially bind to NS1 protein from the ZIKA virus over the NS1 protein from at least one other flavivirus, as described herein, for example, YFV-NS1 from strain 17D, WNV-NS1 from strain NY99, JEV-NS1 from strain SA-14 and TBEV-NS1 from strain Neudoerfl. https://thenativeantigencompany.com/product/flavivirus-nsl-protein-pack. In one embodiment, the other flavivirus is one or more of Dengue virus (DENV), West Nile virus (WN), Yellow fever virus (YF), Tick borne encephalitis virus (TBE), and Japanese Encephalitis virus (JE). In one embodiment, the nanobody preferentially binds the NS1 protein from ZIKV over NS1 protein of the dengue virus.

The term’’preferentially binds” means that the single variable domain antibody binds to ZIKV NS1 with an affinity that is at least 5-fold higher than the affinity to which it binds to NS1 from at least one other flavivirus, as measured by at least one routine assay for assessing antibody-ligand binding affinity. In one embodiment, the single variable domain antibody binds to ZIKV NS1 with an affinity that is at least 10-fold higher than the affinity to which it binds to NS1 from at least one other flavivirus. In one embodiment, the single variable domain antibody binds to ZIKV NS1 with an affinity that is at least 50-fold higher than the affinity to which it binds to NS1 from at least one other flavivirus. In one embodiment, the single variable domain antibody binds to ZIKV NS1 with an affinity that is at least 100-fold higher than the affinity to which it binds to NS1 from at least one other flavivirus. In one embodiment, the single variable domain antibody binds to ZIKV NS1 with an affinity that is at least 1000-fold higher than the affinity to which it binds to NS1 from at least one other flavivirus.

Of course, the definitions and the embodiments described for single variable domain antibodies apply mutatis mutandis to heavy-chain antibodies or polypeptides comprising said single variable domain antibodies.

The term“binding affinity” generally refers to the strength of the sum total of non-covalent interactions between a single binding site of a molecule (e.g., of an antibody) and its binding partner (e.g., an antigen). Unless indicated otherwise, as used herein,“binding affinity”,“bind to”,“binds to” or“binding to” refers to intrinsic binding affinity that reflects a 1: 1 interaction between members of a binding pair (e.g., antibody Fab fragment and antigen). The affinity of a molecule X for its partner Y can generally be represented by the dissociation constant (KD). In this disclosure, binding affinity refers to KD. Affinity can be measured by common methods known in the art, including those described herein. Low-affinity antibodies generally bind antigen slowly and tend to dissociate readily, whereas high-affinity antibodies generally bind antigen faster and tend to remain bound longer. A variety of methods of measuring binding affinity are known in the art, any of which can be used for purposes of the present invention. In one embodiment, the Kd is determined using the method described in the Examples section of this disclosure. In one embodiment, the Kd is determined by competitve ELISA.

The single variable domain antibody of the invention specifically binds to NS1 protein (as opposed to binding any other molecule in the ZIKA virus that is not NS1 protein). Specific binding can be characterized by an equilibrium dissociation constant of at least about lxlO ⁶ M (or lower). Methods for determining whether two molecules bind are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance, radiolabelled assays and the like. In a preferred embodiment, the Kd is determined by surface plasmon resonance analysis. For the avoidance of doubt, it does not mean that a single variable domain antibody of the invention could not bind or interfere, at a low level, to another antigen. Nevertheless, as a preferred embodiment, the single variable domain antibody of the invention binds only to the antigen NS1. In one embodiment, the single variable domain antibody of the invention binds ZIKV NS1 with a Kd of 10 ⁷ or less. In one embodiment, the single variable domain antibody of the invention binds ZIKV NS1 with a Kd from 10 ⁷ to 10 ⁸. In one embodiment, the single variable domain antibody of the invention binds ZIKV NS1 with a Kd from 10 ⁸ to 10 ⁹. In one embodiment, the single variable domain antibody of the invention binds ZIKV NS1 with a Kd from 10 ⁹ to 10 ¹⁰. In one embodiment, the single variable domain antibody of the invention binds ZIKV NS1 with a Kd from 10 ⁹ to 10 ¹². An antibody, heavy-chain antibody, or other polypeptide falls within the scope of this invention, if its affinity for NS1 is within any one of these ranges, as measured by at least one method.

The single variable domain antibodies of the invention can be modified in different ways. In one embodiment, the single variable domain antibodies are conjugated (covalently or non-covalently) or linked to an agent. Alternatively, as described herein, the agent may be conjugated to any amino acid residue within the single variable domain antibodies indirectly, that is, via a linker group. Therefore, as used throughout this disclosure, indirect conjugation means that the agent is conjugated to the linker group, which linker group is conjugated to an amino acid residue within the single variable domain antibodies. The conjugation between the accessory moiety and the linker group and between the linker group and an amino acid residue of the single variable domain antibodies may be any conjugation method and/or compound suitable for effecting such conjugation as described herein or as is otherwise known in the art. The conjugation between the agent and the single variable domain antibodies, whether direct or indirect, may be via a cleavable or non-cleavable linker.

This conjugate can be used in the kits, compositions, assays and methods of the invention.

The antibody molecules of the present invention may additionally be labelled to enable them to be employed for imaging. Techniques for labelling antibodies are well known in the art that enable the antibodies to be used in a range of imaging and spectroscopic applications. In some embodiments, the agent is a detectable label. In one embodiment, label comprises a peptide sequence (e.g., His-tag), an enzyme (such as horseradish peroxidase, alkaline peroxidase, glucose 6-phosphate dehydrogenase, beta-galactosidase, and luciferase, and the like), biotin, streptavidin, an acridinium compound, a radioisotope (such as 3H, 1251, 35S, 14C, 32P, and 33P), a positron emitter, a fluorophore, a chemiluminescent moiety (such as acridinium esters, thioesters, or sulfonamides; luminol, isoluminol, phenanthridinium esters, and the like), rhodamine, phycobiliproteins, R-phycoerythrin, quantum dots (e.g., zinc sulfide-capped cadmium selenide), a thermometric label, an immuno-polymerase chain reaction label, a nuclear magnetic resonance marker, a heavy metal, gold nanoparticles, colored latex beads, magnetic particles, carbon nanoparticles, selenium nanoparticles, silver nanoparticles, quantum dots, up converting phosphors, organic fluorophores, textile dyes, and liposomes.

One particular example of the use of the single variable domain antibodies for imaging involves the use of radionuclide labels in nuclear medicine imaging techniques, such as Single Photon Emission Computed Tomography (SPECT), an imaging technique that detects gamma rays emitted from a radionuclide to produce a two dimensional image of the distribution of the radionuclide in a sample or subject, and Positron Emission Tomography (PET), an imaging technique that three- dimensional images by detecting pairs of gamma rays emitted indirectly by a positron-emitting radionuclide introduced into a sample or subject. Single variable domain antibodies having radionuclide labels may also be employed for multi-modal studies in which imaging techniques are combined, either by selecting radionuclides that are active in more than one imaging technique or by labelling the antibody molecules with more than one type of label.

In some embodiments, the single variable domain antibodies of the present invention may be labelled with a radionuclide, for example a radionuclide provided as a complex, or conjugated to a second molecule, such as a linker, that is associated with the label. Additional examples of radionuclides for use in imaging techniques or therapy include technetium, rhenium, copper, cobalt, gallium and indium isotopes such as Tc-99m, Re-186, Re-188, Co-57, Ga-67, In-111 (SPECT), Cu-64, Cu-60, Cu-61, Cu-62, Cu-67, Tc-94m, Ga-68, Co-55 (PET).

The single variable domain antibodies of the present invention may also be derivatised to modify their properties, and in particular their pharmacological properties, such as half-life (e.g. increasing half-life), or decreasing their immunogenicity. An example is the conjugation of antibody molecules to poly(alkylene glycol) molecules, in particular polyethylene glycol (PEG) molecules, that may be used to enhance the half-life or other pharmacological properties for their use in vivo. Pegylation is a known strategy for modifying the properties of therapeutic polypeptides, such as peptides, proteins and antibodies. In general, the attachment of PEG molecules to polypeptides is used to alter their conformation, electrostatic or hydrophobic properties, and lead to improvements in their biological and pharmacological properties, such as increasing drug solubility, reducing dosage frequency, modulating (especially increasing) circulating half-life, increasing drug stability and increasing resistance to proteolytic degradation Pegylation works by increasing the molecular weight of the therapeutic polypeptide by conjugating the polypeptide to one or more PEG polymer molecules.

In some embodiments, the single variable domain antibodies of the present invention are conjugated to a solid surface or particle. In some embodiments, the solid surface is a flow path in a lateral flow assay device, a well in a microtiter plate, or a flow path in a rotor. The solid surface may be the surface of a microtiter plate. A microtiter plate or multiwell plate typically has, e.g., 6, 12, 24, 48, 96, 384, or 1536 or more sample wells arranged in a 2:3 rectangular matrix. Each well typically holds somewhere between tens of nanoliters to several milliliters of liquid. If a solid particle is used in place of or in addition to a solid surface, it may be a bead. The particle may be a magnetic bead. The bead may be a plastic or synthetic polymer bed comprising: polyethylene, polypropylene, polystyrene, polyamide, polyurethane, phenolic polymer, nitrocellulose, naturally derived polymer, latex rubber, polysaccharide, polypeptide, composite material, ceramic, silica or silica-based material, carbon, metal or metal compound, gold, silver, steel, aluminum, copper, inorganic glass, or silica material, or a combination thereof. The bead may have a spherical, disk, ring, or cube-like shape.

In some embodiments, the single variable domain antibody of the invention comprises three complementarity-determining regions CDR1, CDR2, and CDR3. In some embodiments, the single variable domain antibody comprises only two CDRs (preferably, CDR1 and CDR3). In some embodiments, only the sequence of the antibody CDR1 is any one of the sequences below. In some embodiments, only the sequence of the antibody CDR2 is any one of the sequences below. In some embodiments, only the sequence of the antibody CDR3 is any one of the sequences below. In some embodiments, only the sequence of the antibody CDR1 and CDR2 is any one of the sequences below. In some embodiments, only the sequence of the antibody CDR1 and CDR3 is any one of the sequences below. In some embodiments, only the sequence of the antibody CDR2 and CDR3 is any one of the sequences below. In some embodiments, all of the CDRs of the antibody comprise the sequences described below, but they are combined in a different manner. For example, CDR1 of NSl-1 with CDR3 of NS 1-21. All other alike combinations, although not particularly specified, are still embodiments of this invention. In some embodiments, all three CDRs comprise the following sequences (Table 1):

Table 1. CDR sequences.

The invention also provides for heavy-chain antibodies comprising a variable region (VHH), an hinge, and one or two constant regions (CH2 an CH3), wherein the variable region (VHH) comprises the sequence of any of the single variable domain antibodies discussed elsewhere in this description. In some embodiments, one or more of the constant regions of such heavy-chain antibody is of the IgM, IgG, IgD, IgA, or IgE class.

In some embodiments, the single variable domain antibody of the invention comprises from the N- terminus to the C-Terminus the amino acid sequence SGRTFSNYAMDYAMG (SEQ ID NO: 1), SGRTFS NY AMG (SEQ ID NO: 5), SGRTFYRNTMG (SEQ ID NO: 6), SGFTFSSYPMR (SEQ ID NO: 7), or SGRTFSAYAIG (SEQ ID NO: 8) (corresponding to CDR1), the amino acid sequence AAISWSGGSTYGADSV (SEQ ID NO: 9), AAISGGRTYTRYANSV (SEQ ID NO: 10), AAIS WSGHSTY S ADS V (SEQ ID NO: 11), SAITWSGNSTPYADSV (SEQ ID NO: 12), AAISWSGDSTYPADSV (SEQ ID NO: 13), SIINSDGSSTYYADSV (SEQ ID NO: 14), or AAISGGVVYTRYADFV (SEQ ID NO: 15) (corresponding to CDR2), and the amino acid sequence AAGEVGAFY SDYDLYDY (SEQ ID NO: 3), SASQVGSGLAPTTRDRYAV (SEQ ID NO: 16), A AGP YMT A APRT S S S YKY (SEQ ID NO: 17), ARGRGV SDPGGMD Y (SEQ ID NO: 18), or AAGQVGSGLAPTTRDRYVV (SEQ ID NO: 19) (corresponding to CDR3).

In some embodiments, the single variable domain antibody comprises three complementarity determining regions CDR1, CDR2, and CDR3, wherein the three CDRs comprise the following sets of sequences:

CDR1 (SGRTFSNYAMDYAMG, SEQ ID NO: 1), CDR2 (AAISWSGGSTYGADSV, SEQ ID NO: 9), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

CDR1 (SGRTFSNY AMG, SEQ ID NO: 5), CDR2 (AAISGGRTYTRYANSV, SEQ ID NO: 10), and CDR3 (SASQVGSGLAPTTRDRYAV, SEQ ID NO: 16); CDR1 ( SGRTFS NY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISWSGHSTYSADSV, SEQ ID NO: 11), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

In some embodiments, the single variable domain antibody of the invention comprises one of the following sequences, which represent the sequence of each one of the VHH/nanobodies described in the examples, in order of appearance, NSl-1, NSl-10, NS1-20, NS1-21, NS1-22, NS1-26, and NS1-31:

QVQLVESGGGLVQAGGSLRLYCAASGRTFYRNTMGWFRQVAGKEREFVSAITWSGNST PYADSVKGRFTISRDNAKNTVYLQMNSLKPEDTAVYYCAAGPYMTAAPRTSSSYKYWG QGTQVTVSS (SEQ ID NO: 23); EVQLVESGGGLVQTGGSLRLSCAASGRTFSNYAMDYAMGWFRQAPGKEREFVAAISWS GDSTYPADSVKGRFTISRDNAKNTVLLQMNSLKPEDTAVYYCAAGEVGAFYSDYDLYD YWGQGTQVTVSS (SEQ ID NO: 24);

In some embodiments, the variable region of the heavy chain antibody comprises one of the above 7 amino acid sequences (corresponding to the sequences of the VHH of the examples NSl-1, NS1- 10, NS1-20, NS1-21, NS1-22, NS1-26, and NS 1-31). In some embodiments, any one of these sequences is combined with a constant region, or a part thereof, of the IgM, IgG, IgD, IgA, or IgE class. In some embodiments, the constant region is of human origin.

The disclosed invention also provides for any other polypeptide comprising one of the above 7 amino acid sequences (corresponding to the sequences of the VHH of the examples NS 1-1 , NS1- 10, NS1-20, NS1-21, NS1-22, NS1-26, and NS1-31). In some embodiments, the polypeptide is not any type of antibody. In some embodiments, the polypeptide comprises an immunoglobulin variable domain comprising one of the above 7 amino acid sequences (corresponding to the amino acid sequences of the VHH of the examples NSl-1, NSl-10, NS1-20, NS1-21, NS 1-22, NS1-26, and NS1-31).

In some embodiments, the sequence of the single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention shows an overall degree of sequence homology or identity with the above exemplified polypeptide sequences that is at least about 30 to 40%, and is often greater than about 50%, 60%, 70%, 80%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or more. In some embodiments, the sequence of the antibody or other polypeptide of the invention shows an overall degree of sequence homology or identity with the above exemplified polypeptide sequences that is at least 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91 %, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% over the entire length of the exemplified sequence. In some embodiments, the sequence of the antibody or other polypeptide of the invention shows an overall degree of sequence homology or identity with the above exemplified polypeptide sequences that is at least 60%, 65%, 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 99.9% over the entire lenght of the exemplified sequences.

Also, in the single variable domain antibodies, heavy-chain antibody, or other polypeptide of the invention that comprise the combinations of CDR's mentioned in the above table, each CDR can be replaced by a CDR chosen from the group consisting of amino acid sequences that have at least 80%, preferably at least 90%, more preferably at least 95%, even more preferably at least 99% sequence identity (as defined herein) with the mentioned CDR's; in which (1) any amino acid substitution is preferably a conservative amino acid substitution (as defined herein); and/or (2) said amino acid sequence preferably only contains amino acid substitutions, and no amino acid deletions or insertions, compared to the above amino acid sequence(s); and/or chosen from the group consisting of amino acid sequences that have 3, 2 or only 1 (as indicated in the preceding paragraph) "amino acid difference(s)" (as defined herein) with the mentioned CDR(s), in which: (1) any amino acid substitution is preferably a conservative amino acid substitution (as defined herein); and/or (2) said amino acid sequence preferably only contains amino acid substitutions, and no amino acid deletions or insertions, compared to the above amino acid sequence(s). However, as will be clear to the skilled person, the (combinations of) CDR sequences mentioned in the above table will generally be preferred.

For the purposes of comparing two or more amino acid sequences, the percentage of "sequence identity" between a first amino acid sequence and a second amino acid sequence may be calculated by dividing [the number of amino acid residues in the first amino acid sequence that are identical to the amino acid residues at the corresponding positions in the second amino acid sequence] by [the total number of amino acid residues in the first amino acid sequence] and multiplying by [100%], in which each deletion, insertion, substitution or addition of an amino acid residue in the second amino acid sequence— compared to the first amino acid sequence— is considered as a difference at a single amino acid residue (position), i.e. as an "amino acid difference" as explained below.

Usually, for the purpose of determining the percentage of "sequence identity" between two amino acid sequences in accordance with the calculation method outlined hereinabove, the amino acid sequence with the greatest number of amino acid residues will be taken as the "first" amino acid sequence, and the other amino acid sequence will be taken as the "second" amino acid sequence. Also, in determining the degree of sequence identity between two amino acid sequences, the skilled person may take into account so-called "conservative" amino acid substitutions, which can generally be described as amino acid substitutions in which an amino acid residue is replaced with another amino acid residue of similar chemical structure and which has little or essentially no influence on the function, activity or other biological properties of the polypeptide. Such conservative amino acid substitutions are well known in the art, for example from WO 04/037999, GB-A-2 357 768, WO 98/49185, WO 00/46383 and WO 01/09300; and (preferred) types and/or combinations of such substitutions may be selected on the basis of the pertinent teachings from WO 04/037999 as well as WO 98/49185 and from the further references cited therein.

In some embodiments, conserved amino acid substitutions are made on the basis of similarity in polarity, charge, solubility, hydrophobicity, hydrophilicity, and/or the amphipathic nature of the residues involved. For example, nonpolar (hydrophobic) amino acids include alanine (Ala, A), leucine (Leu, L), isoleucine (lie, I), valine (Val, V), proline (Pro, P), phenylalanine (Phe, F), tryptophan (Trp, W), and methionine (Met, M); polar neutral amino acids include glycine (Gly, G), serine (Ser, S), threonine (Thr, T), cysteine (Cys, C), tyrosine (Tyr, Y), asparagine (Asn, N), and glutamine (Gin, Q); positively charged (basic) amino acids include arginine (Arg, R), lysine (Lys, K), and histidine (His, H); and negatively charged (acidic) amino acids include aspartic acid (Asp, D) and glutamic acid (Glu, E).

In some embodiments, such conservative substitutions preferably are substitutions in which one amino acid within the following groups (a)-(e) is substituted by another amino acid residue within the same group: (a) small aliphatic, nonpolar or slightly polar residues: Ala, Ser, Thr, Pro and Gly; (b) polar, negatively charged residues and their (uncharged) amides: Asp, Asn, Glu and Gin; (c) polar, positively charged residues: His, Arg and Lys; (d) large aliphatic, nonpolar residues: Met, Leu, lie, Val and Cys; and (e) aromatic residues: Phe, Tyr and Trp. Particularly preferred conservative substitutions are as follows: Ala into Gly or into Ser; Arg into Lys; Asn into Gin or into His; Asp into Glu; Cys into Ser; Gin into Asn; Glu into Asp; Gly into Ala or into Pro; His into Asn or into Gin; He into Leu or into Val; Leu into He or into Val; Lys into Arg, into Gin or into Glu; Met into Leu, into Tyr or into He; Phe into Met, into Leu or into Tyr; Ser into Thr; Thr into Ser; Trp into Tyr; Tyr into Trp; and/or Phe into Val, into He or into Leu.

Any amino acid substitutions applied to the polypeptides described herein may also be based on the analysis of the frequencies of amino acid variations between homologous proteins of different species developed by Schulz et al., Principles of Protein Structure, Springer- Verlag, 1978, on the analyses of structure forming potentials developed by Chou and Fasman, Biochemistry 13: 211, 1974 and Adv. Enzymol., 47: 45-149, 1978, and on the analysis of hydrophobicity patterns in proteins developed by Eisenberg et al., Proc. Nad. Acad. Sci. USA 81: 140-144, 1984; Kyte & Doolittle; J Molec. Biol. 157: 105-132, 198 1, and Goldman et al., Ann. Rev. Biophys. Chem. 15: 321-353, 1986, all incorporated herein in their entirety by reference. Information on the primary, secondary and tertiary structure of Nanobodies are given in the description herein and in the general background art cited above. Also, for this purpose, the crystal structure of a VHH domain from a llama is for example given by Desmyter et al., Nature Structural Biology, Vol. 3, 9, 803 (1996); Spinelli et al., Natural Structural Biology (1996); 3, 752-757; and Decanniere et al., Structure, Vol. 7, 4, 361 (1999). Further information about some of the amino acid residues that in conventional VH domains form the VH/VL interface and potential camelizing substitutions on these positions can be found in the prior art on Nanobodies.

The invention also provides for nucleic acids encoding any one of the single variable domain antibodies, heavy-chain antibody, or other polypeptide disclosed herein. In some preferred embodiments, the nucleic acids comprise any one of the following sequences, or codon-optimized versions of the same:

>NS1-1

CAGTTGCAGCTCGTGGAGTCCGGGGGAGGATTGGTGCAGACTGGGGGCTCTCTGAG ACTCTCCTGTGCAGCCTCTGGACGCACCTTCAGTAACTATGCCATGGATTATGCCATG GGCTGGTTCCGCCAGGCTCCAGGGAAGGAGCGTGAGTTTGTAGCAGCTATTAGCTGG AGTGGTGGTAGCACATACGGTGCAGACTCCGTGAAGGGCCGATTCACCATCTCCAGA GACAACGCCAAGAACACGGTGTATCTGCAAATGAACAGCCTGAAACCTGAGGACAC GGCCGTTTATTACTGTGCGGCCGGAGAAGTGGGGGCTTTCTATAGCGACTATGACTT GTATGACTACTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCAGAACCCAAGACACC AAAACCACAACCA (SEQ ID NO: 27);

>NS1-10

GAGGTGCAGCTGGTAGAGTCTGGGGGAGGATTGGTGCAGCCTGGGGGCTCTCTGAG ACTCTCCTGTGCCGCCTCTGGACGCACCTTCAGTAATTATGCCATGGGCTGGTTCCGC CAGGCTCCAGAAAAGGAGCGTGAGTTTGTAGCAGCTATTAGTGGGGGTCGTACTTAC ACACGCTATGCGAACTCCGTGAAGGGCCGATTCACCATCTCCAGAGACAACGCCAA GAACACGGTGTATCTGCAAATGAACAGCCTGGAACCTGAGGACACGGCCGTTTATTA CTGTTCGGCGAGTCAGGTTGGGAGCGGACTAGCTCCTACTACACGTGATCGGTATGC CGTCTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCAGAACCCAAGACACCAAAAC CACAACCA (SEQ ID NO: 28);

>NSl-20

GAGGTGCAGCTGGTAGAGTCTGGGGGAGGATTGGTGCAGACTGGGGGCTCTCTGAG ACTCTCCTGTGCAGCCTCTGGACGCACCTTCAGTAACTATGCCATGGATTATGCCATG GGCTGGTTCCGCCAGGCTCCAGGGGAGGAGCGTGAGTTTGTAGCAGCTATTAGCTGG AGTGGTCATAGCACATACTCTGCAGACTCCGTGAAGGGCCGATTCACCATCTCCAGA GACAACGCCAAGAACACGGTGTATCTGCAAATGAACAGCCTGAAACCTGAGGACAC GGCCGTTTATTACTGTGCAGCCGGAGAAGTGGGGGCTTTCTATAGCGACTATGACTT GTATGACTACTGGGGCCAGGGGATCCAGGTCACCGTCTCCTCAGAACCCAAGACACC AAAACCACAACCA (SEQ ID NO: 29);

>NS1-21

CAGGTGCAGCTCGTGGAGTCTGGGGGAGGATTGGTGCAGGCTGGGGGCTCTCTGAG ACTCTACTGTGCAGCCTCTGGACGCACCTTCTATAGAAATACCATGGGCTGGTTCCG CCAGGTTGCAGGGAAGGAGCGTGAGTTTGTGTCAGCGATTACCTGGAGTGGGAATA GCACACCCTATGCAGACTCTGTGAAGGGCCGATTCACCATCTCCAGAGATAACGCCA AGAACACGGTGTACCTGCAAATGAACAGCCTGAAACCTGAGGACACGGCCGTTTATT ACTGTGCAGCGGGGCCCTATATGACGGCCGCACCCCGGACCTCCAGTTCGTATAAGT ACTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 30);

>NSl-22

GAGGTGCAGCTGGTAGAGTCTGGGGGAGGATTGGTGCAGACTGGGGGCTCTCTGAG ACTCTCCTGTGCAGCCTCTGGACGCACCTTCAGTAACTATGCCATGGATTATGCCATG GGCTGGTTCCGCCAGGCTCCAGGGAAGGAGCGTGAGTTTGTAGCAGCTATTAGCTGG AGTGGTGATAGCACATACCCTGCAGACTCCGTGAAGGGCCGATTCACCATCTCCAGA GACAACGCCAAGAACACGGTGCTTCTGCAAATGAACAGCCTGAAACCTGAGGACAC GGCCGTTTATTACTGTGCAGCCGGAGAAGTGGGGGCTTTCTATAGCGACTATGACTT GTATGACTACTGGGGCCAGGGGACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 31); >NSl-26 CAGGTGCAGCTCGTGGAGTCAGGGGGAGGCTTGGTGCAACCTGGGGGGTCTCTGAG ACTCTCCTGTGCAGCCTCTGGATTCACCTTTAGTAGCTATCCTATGAGATGGGTCCGC CAGGCTCCAGGAAAGGGGCTCGAGCGGGTCTCAATTATTAATAGTGATGGTAGTAGC ACATACTATGCAGACTCCGTGAAGGGCCGGTTCACCATCTCCAGAGACAACGCCAAG AACACGCTGTATCTGCAAATGAACAGCCTGAAACCTGAGGACACGGGCGTGTATTAC TGTGCAAGAGGGCGAGGAGTAAGTGATCCGGGGGGCATGGACTATCGGGGCAAAGG GACCCAGGTCACCGTCTCCTCA (SEQ ID NO: 32); and

>NS1-31

In some embodiments, the nucleotide sequences encoding the single variable domain antibodies, heavy-chain antibody, or other polypeptide of the invention are at least about 60%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% identical to any one of the sequences exemplified above. In some embodiments, the nucleotide sequences encoding the antibodies and other polypeptides of the invention are at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or more identical to those sequences exemplified above. For example, codon-optimized verrsions of the above listed sequences can be generated by one of ordinary skill in the art.

For the purposes of comparing two or more nucleotide sequences, the percentage of "sequence identity" between a first nucleotide sequence and a second nucleotide sequence may be calculated by dividing [the number of nucleotides in the first nucleotide sequence that are identical to the nucleotides at the corresponding positions in the second nucleotide sequence] by [the total number of nucleotides in the first nucleotide sequence] and multiplying by [100%], in which each deletion, insertion, substitution or addition of a nucleotide in the second nucleotide sequence— compared to the first nucleotide sequence— is considered as a difference at a single nucleotide (position). Usually, for the purpose of determining the percentage of "sequence identity" between two nucleotide sequences in accordance with the calculation method outlined hereinabove, the nucleotide sequence with the greatest number of nucleotides will be taken as the "first" nucleotide sequence, and the other nucleotide sequence will be taken as the "second" nucleotide sequence. A nucleic acid of the invention can be in the form of single or double stranded DNA or RNA, and is preferably in the form of double stranded DNA. For example, the nucleotide sequences of the invention may be genomic DNA, cDNA or synthetic DNA (such as DNA with a codon usage that has been specifically adapted for expression in the intended host cell or host organism). The nucleic acid of the invention may also be in the form of, be present in and/or be part of a vector, such as for example a plasmid, cosmid or YAC, which again may be in essentially isolated form.

The nucleic acids of the invention can be prepared or obtained in a manner known per se, based on the information on the amino acid sequences for the polypeptides of the invention given herein, and/or can be isolated from a suitable natural source. To provide analogs, nucleotide sequences encoding naturally occurring VHH domains can for example be subjected to site-directed mutagenesis, so as to provide a nucleic acid of the invention encoding said analog. Also, as will be clear to the skilled person, to prepare a nucleic acid of the invention, also several nucleotide sequences, such as at least one nucleotide sequence encoding a single variable domain antibody, VHH, or peptide, and for example nucleic acids encoding one or more linkers can be linked together in a suitable manner.

Techniques for generating the nucleic acids of the invention will be clear to the skilled person and may for instance include, but are not limited to, automated DNA synthesis; site-directed mutagenesis; combining two or more naturally occurring and/or synthetic sequences (or two or more parts thereof), introduction of mutations that lead to the expression of a truncated expression product; introduction of one or more restriction sites (e.g. to create casettes and/or regions that may easily be digested and/or ligated using suitable restriction enzymes), and/or introduction of mutations by means of a PCR reaction using one or more "mismatched" primers, using for example a sequence of a naturally occurring GPCR as a template. These and other techniques will be clear to the skilled person, and reference is again made to the standard handbooks, such as Sambrook et al. and Ausubel et ah, as well as the Examples below.

The nucleic acid of the invention may also be in the form of, be present in and/or be part of a genetic construct such as a vector, as will be clear to the person skilled in the art. Such genetic constructs generally comprise at least one nucleic acid of the invention that is optionally linked to one or more elements of genetic constructs known per se, such as for example one or more suitable regulatory elements (such as a suitable promoter(s), enhancer(s), terminator(s), etc.) and the further elements of genetic constructs referred to hereinbelow. In one embodiment, the vector is an expression vector wherein the expression vector comprises: a) the single variable domain antibody, heavy-chain antibody, or other polypeptide expression cassette; b) a selection marker expression cassette, wherein the expression cassettes are arranged unidirectional, and wherein the expression cassettes are arranged in the 5' to 3' sequence of single variable domain antibody, heavy-chain antibody, or other polypeptide expression cassette and selection marker expression cassette. In some embodiments, the expression cassette comprises in 5' to 3' direction a promoter, a nucleic acid encoding the single variable domain antibody, heavy-chain antibody, or other polypeptide, a polyA signal sequence, and optionally a terminator sequence.

The genetic constructs of the invention may be DNA or RNA, and are preferably double-stranded DNA. The genetic constructs of the invention may also be in a form suitable for transformation of the intended host cell or host organism, in a form suitable for integration into the genomic DNA of the intended host cell or in a form suitable for independent replication, maintenance and/or inheritance in the intended host organism. For instance, the genetic constructs of the invention may be in the form of a vector, such as for example a plasmid, cosmid, YAC, a viral vector or transposon. In particular, the vector may be an expression vector, i.e. a vector that can provide for expression in vitro and/or in vivo (e.g. in a suitable host cell, host organism and/or expression system).

In a preferred but non-limiting embodiment, a genetic construct of the invention comprises a) at least one nucleic acid of the invention; operably connected to b) one or more regulatory elements, such as a promoter and optionally a suitable terminator; and optionally also c) one or more further elements of genetic constructs known per se; in which the terms "regulatory element", "promoter", "terminator" and "operably connected" have their usual meaning in the art (as further described below); and in which said "further elements" present in the genetic constructs may for example be 3'- or 5'-UTR sequences, leader sequences, selection markers, expression markers/reporter genes, and/or elements that may facilitate or increase (the efficiency of) transformation or integration. These and other suitable elements for such genetic constructs will be clear to the skilled person, and may for instance depend upon the type of construct used, the intended host cell or host organism; the manner in which the nucleotide sequences of the invention are to be expressed (e.g. via constitutive, transient or inducible expression); and/or the transformation technique to be used. In some embodiments, in the genetic constructs of the invention, said at least one nucleic acid of the invention and said regulatory elements, and optionally said one or more further elements, are "operably linked" to each other, by which is generally meant that they are in a functional relationship with each other. For instance, a promoter is considered "operably linked" to a coding sequence if said promoter is able to initiate or otherwise control/regulate the transcription and/or the expression of a coding sequence (in which said coding sequence should be understood as being "under the control of" said promotor). Generally, when two nucleotide sequences are operably linked, they will be in the same orientation and usually also in the same reading frame. They will usually also be essentially contiguous, although this may also not be required.

In some embodiments, the regulatory and further elements of the genetic constructs of the invention are such that they are capable of providing their intended biological function in the intended host cell or host organism.

For instance, a promoter, enhancer or terminator should be "operable" in the intended host cell or host organism, by which is meant that (for example) said promoter should be capable of initiating or otherwise controlling/regulating the transcription and/or the expression of a nucleotide sequence— e.g. a coding sequence— to which it is operably linked (as defined herein).

Some particularly preferred promoters include, but are not limited to, promoters known per se for the expression in bacterial cells, such as those mentioned hereinbelow and/or those used in the Examples.

A selection marker should be such that it allows— i.e. under appropriate selection conditions— host cells and/or host organisms that have been (succesfully) transformed with the nucleotide sequence of the invention to be distinguished from host cells/organisms that have not been (succesfully) transformed. Some preferred, but non-limiting examples of such markers are genes that provide resistance against antibiotics (such as kanamycine or ampicilline), genes that provide for temperature resistance, or genes that allow the host cell or host organism to be maintained in the absence of certain factors, compounds and/or (food) components in the medium that are essential for survival of the non-transformed cells or organisms.

A leader sequence should be such that— in the intended host cell or host organism— it allows for the desired post-translational modifications and/or such that it directs the transcribed mRNA to a desired part or organelle of a cell. A leader sequence may also allow for secretion of the expression product from said cell. As such, the leader sequence may be any pro-, pre-, or prepro-sequence operable in the host cell or host organism. Leader sequences may not be required for expression in a bacterial cell.

An expression marker or reporter gene should be such that— in the host cell or host organism— it allows for detection of the expression of (a gene or nucleotide sequence present on) the genetic construct. An expression marker may optionally also allow for the localisation of the expressed product, e.g. in a specific part or organelle of a cell and/or in (a) specific cell(s), tissue(s), organ(s) or part(s) of a multicellular organism. Such reporter genes may also be expressed as a protein fusion with the amino acid sequence of the invention. Some preferred, but non-limiting examples include fluorescent proteins such as GFP.

Some preferred, but non-limiting examples of suitable promoters, terminator and further elements include those used in the Examples below. Some preferred, but non-limiting promoters for use with a variety of host cells include, for expression in E. coli: lac promoter (and derivatives thereof such as the lacUV5 promoter); arabinose promoter; left- (PL) and rightward (PR) promoter of phage lambda; promoter of the trp operon; hybrid lac/trp promoters (tac and trc); T7 -promoter (more specifically that of T7-phage gene 10) and other T-phage promoters; promoter of the TnlOO tetracycline resistance gene; engineered variants of the above promoters that include one or more copies of an extraneous regulatory operator sequence; for expression in S. cerevisiae: constitutive: ADH1 (alcohol dehydrogenase 1), ENO (enolase), CYC1 (cytochrome c iso-1), GAPDH (glyceraldehydes-3 -phosphate dehydrogenase); PGK1 (phosphoglycerate kinase), PYK1 (pyruvate kinase); regulated: GAL1,10,7 (galactose metabolic enzymes), ADH2 (alcohol dehydrogenase 2), PH05 (acid phosphatase), CUP1 (copper metallothionein); heterologous: CaMV (cauliflower mosaic virus 35S promoter); for expression in Pichia pastoris: the AOX1 promoter (alcohol oxidase I) for expression in mammalian cells: human cytomegalovirus (hCMV) immediate early enhancer/promoter; human cytomegalovirus (hCMV) immediate early promoter variant that contains two tetracycline operator sequences such that the promoter can be regulated by the Tet repressor; Herpes Simplex Virus thymidine kinase (TK) promoter; Rous Sarcoma Virus long terminal repeat (RSV LTR) enhancer/promoter; elongation factor 1.alpha. (hEF-1.alpha.) promoter from human, chimpanzee, mouse or rat; the SV40 early promoter; HIV-1 long terminal repeat promoter; .beta.-actin promoter. Some preferred, but non-limiting vectors include: vectors for expression in mammalian cells: pMAMneo (Clontech), pcDNA3 (Invitrogen), pMClneo (Stratagene), pSG5 (Stratagene), EBO-pSV2-neo (ATCC 37593), pBPV-1 (8-2) (ATCC 37110), pdBPV-MMTneo (342-12) (ATCC 37224), pRSVgpt (ATCC37199), pRSVneo (ATCC37198), pSV2-dhfr (ATCC 37146), pUCTag (ATCC 37460) and 1ZD35 (ATCC 37565), as well as viral- based expression systems, such as those based on adenovirus; vectors for expression in bacterials cells: pET vectors (Novagen) and pQE vectors (Qiagen); vectors for expression in yeast or other fungal cells: pYES2 (Invitrogen) and Pichia expression vectors (Invitrogen); vectors for expression in insect cells: pBlueBacII (Invitrogen) and other baculovirus vectors vectors for expression in plants or plant cells: for example vectors based on cauliflower mosaic virus or tobacco mosaic virus, suitable strains of Agrobacterium, or Ti-plasmid based vectors. Some preferred, but non limiting secretory sequences include: for use in bacterial cells such as E. coli: PelB, Bla, OmpA, OmpC, OmpF, OmpT, StII, PhoA, PhoE, MalE, Lpp, LamB, and the like; TAT signal peptide, hemolysin C-terminal secretion signal for use in yeast: alpha-mating factor prepro-sequence, phosphatase (phol), invertase (Sue), and others; for use in mammalian cells: indigenous signal in case the target protein is of eukaryotic origin; murine Ig kappachain V-J2-C signal peptide, and others.

For some (further) non-limiting examples of the promoters, selection markers, leader sequences, expression markers and further elements that may be present/used in the genetic constructs of the invention— such as terminators, transcriptional and/or translational enhancers and/or integration factors— reference is made to the general handbooks such as Sambrook et al. and Ausubel et al. mentioned above. Other examples will be clear to the skilled person. Reference is also made to the general background art cited above and the further references cited hereinbelow.

Often, the genetic constructs of the invention will be obtained by inserting a nucleotide sequence of the invention in a suitable (expression) vector known per se. Some preferred, but non-limiting examples of suitable expression vectors are those used in the Examples below, as well as those mentioned below.

The nucleic acids of the invention and/or the genetic constructs of the invention may be used to transform a host cell or host organism. The host cell or host organism may be any suitable (fungal, prokaryotic or eukaryotic) cell or cell line or any suitable fungal, prokaryotic or eukaryotic organism, for example: a bacterial strain, including but not limited to gram-negative strains such as strains of Escherichia coli ; of Proteus , for example of Proteus mirabilis of Pseudomonas, for example of Pseudomonas fluorescens and gram-positive strains such as strains of Bacillus, for example of Bacillus subtilis or of Bacillus brevis, of Streptomyces , for example of Streptomyces lividans; of Staphylococcus, for example of Staphylococcus carnosus, and of Lactococcus, for example of Lactococcus lactis a fungal cell, including but not limited to cells from species of Trichoderma, for example from Trichoderma reesei; of Neurospora, for example from Neurospora crassa; of Sordaria, for example from Sordaria macrospora; of Aspergillus, for example from Aspergillus niger or from Aspergillus sojae or from other filamentous fungi; a yeast cell, including but not limited to cells from species of Saccharomyces, for example of Saccharomyces cerevisiae; of Schi/osaccharomycev, for example of Schizosaccharomyces pombe; of Pichia, for example of Pichia pastoris or of Pichia methanolica; of Hansenula, for example of Hansenula polymorpha; of Kluyveromyces , for example of Kluyveromyces lactis, of Arxula, for example of Arxula adeninivorans; of Yarrowia, for example of Yarrowia lipolytica ; an amphibian cell or cell line, such as Xenopus oocytes; an insect-derived cell or cell line, such as cells/cell lines derived from lepidoptera, including but not limited to Spodoptera SF9 and Sf21 cells or cells/cell lines derived from Drosophila, such as Schneider and Kc cells; a plant or plant cell, for example in tobacco plants; and/or a mammalian cell or cell line, for example a cell or cell line derived from a human, from the mammals including but not limited to HEK293 cells, NSO cells, CHO-cells, BHK-cells (for example BHK-21 cells) and human cells or cell lines such as HeLa, COS (COS, e.g., COS-1, COS-7), PER.C6, BSC-1, human hepatocellular carcinoma cells (e.g., Hep G2), SP2/0, HeLa, Madin-Darby bovine kidney (MDBK), myeloma and lymphoma cells, as well as all other hosts or host cells known per se for the expression and production of antibodies which will be clear to the skilled person. Engineered variants include, e.g., glycan profile modified and/or site-specific integration site derivatives. Reference is also made to the general background art cited hereinabove, as well as to for example WO 94/29457; WO 96/34103; WO 99/42077and the further references cited herein.

In some embodiments, the single variable domain antibodies, heavy-chain antibody, or other polypeptide of the invention are produced in mammalian cell lines, in particular Chinese hamster ovary (CHO) cells, which can be used for large scale expression/production/fermentation, and in particular for large scale pharmaceutical expression/production/fermentation. Such expression/production systems are commercially avaiable. In some embodiments, the single variable domain antibodies of the invention may also be expressed as so-called "intrabodies", as for example described in WO 94/02610, WO 95/22618 and U.S. Pat. No. 7,004,940; WO 03/014960; in Cattaneo, A. & Biocca, S. (1997) Intracellular Antibodies: Development and Applications. Landes and Springer- Verlag; and in Kontermann, Methods 34, (2004), 163-170.

In some embodiments, the antibodies and polypeptides of the invention can for example also be produced in the milk of transgenic mammals, for example in the milk of rabbits, cows, goats or sheep (see for example U.S. Pat. Nos. 6,741,957, 6,304,489 and 6,849,992 for general techniques for introducing transgenes into mammals), in plants or parts of plants including but not limited to their leaves, flowers, fruits, seed, roots or tubers (for example in tobacco, maize, soybean or alfalfa) or in for example pupae of the silkworm Bombyx mori.

Furthermore, the antibodies and polypeptides of the invention can also be expressed and/or produced in cell-free expression systems, and suitable examples of such systems will be clear to the skilled person. Some preferred, but non-limiting examples include expression in the wheat germ system; in rabbit reticulocyte lysates; or in the E. coli Zubay system.

The choice of the specific expression system would depend in part on the requirement for certain post-translational modifications .

The invention also provides for compositions comprising one or more of the single variable domain antibodies, heavy-chain antibody, or other polypeptide described herein. The invention also provides for compositions comprising one or more of the nucleic acids described herein.

Compositions comprising the subject single variable domain antibody, heavy-chain antibody, or other polypeptideor comprising the subject nucleic acids may comprise one or more suitable excipients or pharmaceutically acceptable carriers, one or more additional ingredients, or some combination of these. Particularly, the antibodies or other polypeptides may be provided as dry powders, usually lyophilized, including excipients which on dissolution will provide an antibody solution having the appropriate concentration.

In preferred but non-limitating embodiments, the compositions comprise at least 1 ng/ml, preferably at least 10 ng/ml, more preferably at least 100 ng/ml of the single variable domain antibodies, heavy-chain antibody, or other polypeptide described herein. In preferred but non-limitating embodiments, the compositions comprise at least 1 ng/ml, 5 ng/ml, 10 ng/ml, 50 ng/ml, 100 ng/ml, 500 ng/ml, 1 mg/ml, 5 mg/ml or 10 mg/ml of the single variable domain antibodies, heavy-chain antibody, or other polypeptide described herein.

In another aspect, the invention provides a substrate, such as a solid support (e.g., an insoluble substrate, such as a plate or slide made of glass, plastic or metal, a polymer-coated bead, a tube, or a ceramic or metal chip) that comprises immobilized (or otherwise deposited) one or more of the antibodies of the invention. In some embodiments, the antibodies are immobilized (or deposited) at discrete locations (e.g., in the wells of a multiwall plate, or deposited in an array on a biochip). In some embodiments, the substrate comprising the antibodies may be part of a kit for detecting NS1 in a biological sample obtained from a subject.

The invention also provides methods of detecting ZIKV, in particular ZIKV NS1 protein, in a sample using a single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention. In some embodiments, the methods are diagnostic methods, in particular for diagnosing ZIKA virus infection. In some embodiments, the methods are able to detect ZIKV NS1 protein in vivo. In other embodiments, the methods are able to detect ZIKV NS1 protein in vitro. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

In some embodiments, the sample is a biological sample. In some embodiments, the biological sample comprises blood, plasma, serum, saliva, cerebrospinal fluid, a tissue biopsy, cells isolated from a subject being tested (e.g., immune cells, cells isolated from cheeks or gums), cells grown and/or processed in vitro, aqueous humour, vitreous humour, bile, breast milk, endolymph, perilymph gastric juice, mucus, peritoneal fluid, pleural fluid, sebum, semen, sweat, tears, vaginal secretion, vomit, or urine. In one embodiment, the biological sample comprises blood. In one embodiment, the biological sample comprises serum.

In some embodiments, the invention provides methods of detecting NS1 protein as a surrogate for the presence of or infection by ZIKV in the source of the sample using any one of the antibodies of the invention. A method of detecting ZIKV in a biological sample comprising (i) contacting the biological sample with an anti-NSl single variable domain antibody, heavy-chain antibody, or other polypeptide under conditions permissive for binding of the anti-NSl single variable domain antibody, heavy-chain antibody, or other polypeptide to ZIKV NS1 protein in the sample and (ii) detecting whether a complex is formed between the anti-NSl single variable domain antibody, heavy-chain antibody, or other polypeptide and the ZIKV NS1 protein in the biological sample, wherein detection of the formation of the complex indicates the presence of ZIKV in the sample. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

In some embodiments, the presence of ZIKV NS1 in a sample from a subject indicates that the subject is or has been infected with ZIKV or is diagnostic of ZIKV infection.

The single variable domain antibody, heavy-chain antibody, or other polypeptide can be used diagnostically (in vivo, in situ or in vitro ) to, for example, monitor the development or progression of a ZIKV infection as part of a clinical testing procedure to, e.g., determine the efficacy of a given treatment regimen. Detection can be facilitated by coupling the single variable domain antibody, heavy-chain antibody, or other polypeptideto a detectable label, as described elsewhere in this specification.

The invention also provides for diagnostic agents comprising a single variable domain antibody, heavy-chain antibody, or other polypeptide described herein linked directly or indirectly, covalently or non-covalently to a substance of interest, especially a detectable label, as described elsewhere in the specification.

Various methods of in vivo diagnostic imaging with radiolabeled antibodies are well known in the art and these and other labels suitable for detection of NS1 in vivo with the antibodies of the invention are described elsewhere in this specification (e.g. PET).

In some embodiments, the detection method is by Western Blotting, immunoprecipitation, immunocytochemistry, immunohistochemistry, immunoelectron microscopy, radioimmunoassay, optical immunoassay, Enzyme-Linked ImmunoSpot (ELISPOT) assay, 2D gel electrophoresis, digital enzyme-linked immunosorbent assay (ELISA), or analog ELISA, such as enzyme multiplied immunoassay technique (EMIT), enzyme-linked immunosorbent assay (ELISA), IgM antibody capture ELISA (MAC ELISA), and microparticle enzyme immunoassay (MEIA); capillary electrophoresis immunoassays (CEIA); radioimmunoassays (RIA); immunoradiometric assays (IRMA); fluorescence polarization immunoassays (FPIA); and chemiluminescence assays (CL). For example, by radioactively labeling an antibody, it is possible to detect the antibody through the use of radioimmune assays. In some embodiments, the detection method is by sandwich or antigen capture ELISA. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

In some embodiments of a "sandwich ELISA", a first antibody (e.g. anti-NSl) is linked to a solid phase (i.e. a microtiter plate) and exposed to a biological sample containing antigen (e.g. NS1). The solid phase is then washed to remove unbound antigen. A second labeled antibody (e.g. enzyme linked) is then bound to the bound-antigen (if present) forming an antibody- anti gen- antibody sandwich. Examples of enzymes that can be linked to the antibody are provided elsewhere in this application, whereby the enzymes are characterized as detectable labels. In one embodiment, the enzyme linked antibody reacts with a substrate to generate a colored reaction product that can be measured. In some embodiments, the reaction can be quantified. The scoring may be carried out by standard colour development (e.g. secondary antibody with horseradish peroxidase and tetramethyl benzidine with hydrogenperoxide). The reaction in certain wells is scored by the optical density, for example at 450 nm. Typical background (=negative reaction) may be 0.1 OD, typical positive reaction may be 1 OD. This means the difference (ratio) positive/negative can be more than 10 fold. In some embodiments, the first antibody is a single variable domain antibody, heavy- chain antibody, or other polypeptide of the invention and the second antibody is any other anti- NSl antibody (e.g., one that binds to a different epitope of NS1). In some embodiments, the first antibody is any anti-NSl antibody (e.g., one that binds to a different epitope of NS1 that those of the invention) and the second antibody is a single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention. In some embodiments, the anti-NSl antibody (e.g., one that binds to a different epitope of NS1 that those of the invention) is cross-reactive against more than one flavi virus NS1 protein.

Various protocols for immunoassays are well known in art. For example, a conventional sandwich assay can be used with an analog detection method, or a conventional competitive assay format can be used with an analog detection method. In other embodiments, the detection method is digital. For a discussion of some suitable types of assays, see Current Protocols in Immunology. In certain embodiments, an single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention is immobilized on a solid or semi -solid surface or carrier by means of covalent or non-covalent binding, either prior to or after the addition of the sample containing the NS1 protein. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

Devices for performing specific binding assays, especially immunoassays, are known and can be readily adapted for use in the present methods. Solid phase assays, in general, are easier to perform than heterogeneous assay methods which require a separation step, such as precipitation, centrifugation, filtration, chromatography, or magnetism, because separation of reagents is faster and simpler. Solid-phase assay devices include microtiter plates, flow-through assay devices (e.g., lateral flow immunoassay devices), dipsticks, and immunocapillary or immunochromatographic immunoassay devices.

In some embodiments of the invention, the single variable domain antibody, heavy-chain antibody, or other polypeptide is provided with a suitable label which enables detection. Conventional labels may be used which are capable, alone or in concert with other compositions or compounds, of providing a detectable signal. Suitable labels include, but are not limited to, enzymes (e.g., HRP, beta-galactosidase, alkaline phosphatase, etc.), fluorescent labels, radioactive labels, colored latex particles, and metal-conjugated labels (e.g., metallic nanolayers, metallic nanoparticle- or metallic nanoshell-conjugated labels). Suitable metallic nanoparticle or metallic nanoshell labels include, but are not limited to, gold particles, silver particles, copper particles, platinum particles, cadmium particles, composite particles, gold hollow spheres, gold-coated silica nanoshells, and silica-coated gold shells. Metallic nanolayers suitable for detectable layers include nanolayers comprised of cadmium, zinc, mercury, and noble metals, such as gold, silver, copper, and platinum. Additional suitable agents that can be conjugated to the single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention for detection purposes have been described in detail above.

In a preferred embodiment, the detection assay is a sandwich ELISA or antigen-capture ELISA. A detailed example of such assay is described in the Examples section. In an embodiment of an ELISA, a first anti-NSl protein antibody that crossreacts with the NS1 protein of different flavivirus is immobilized on a surface, such as a ninety-six-well ELISA plate or equivalent solid phase. The plates are then incubated with a biological sample (or, for a positive control, purified NS1 protein). The immobilized first antibody binds to the NS1 protein in the biological sample and the excess is washed off. The plate is then incubated with one or more of the antibodies of the invention, which would preferentially bind, or only bind to, the NS1 protein already bound to or captured by the first anti-NSl antibody coating the plate if that protein is ZIKV NS1. After a suitable number of washes with standard washing buffers, the antibody of the invention that is bound to the captured NS1 is detected by any appropriate method. Conditions for performing ELISA assays are well-known in the art. In a preferred embodiment, the antibody of the invention is strep-tagged and it is detected with an anti-strep tagged antibody. The amount of NS1 protein in the sample may then be measured through a calibration curve. In this preferred embodiment, the single variable domain antibody, heavy-chain antibody or other polypeptide of the invention serves as the detection antibody. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

In an embodiment of an ELISA, any first anti-NSl protein antibody that binds ZIKV NS1 (not cross-reactive) is immobilized on a surface, such as a ninety-six-well ELISA plate or equivalent solid phase. The plates are then incubated with a biological sample (or, for a positive control, purified NS1 protein). The immobilized first antibody binds to the NS1 protein in the biological sample and the excess is washed off. The plate is then incubated with one or more single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention that binds to NS1 protein already bound to or captured by the first anti-NSl antibody coating the plate if that protein is ZIKV NS1. After a suitable number of washes with standard washing buffers, the single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention that is bound to the captured NS1 is detected by any appropriate method. Conditions for performing ELISA assays are well-known in the art. In a preferred embodiment, the antibody of the invention is strep-tagged and it is detected with an anti-strep tagged antibody. The amount of NS1 protein in the sample may then be measured through a calibration curve. In this preferred embodiment, the single variable domain antibody, heavy-chain antibody or other polypeptide of the invention serves as the detection antibody. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

In an embodiment of an ELISA, one or more of the first single variable domain antibody, heavy- chain antibody, or other polypeptide of the invention is immobilized on a surface, such as a ninety- six-well ELISA plate or equivalent solid phase. The plates are then incubated with a biological sample (or, for a positive control, purified NS1 protein). The immobilized first antibody binds to the NS1 protein in the biological sample and the excess is washed off. The plate is then incubated with one or more single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention that binds to NS1 protein already bound to or captured by the first anti-NSl antibody coating the plate if that protein is ZIKV NS1. After a suitable number of washes with standard washing buffers, any first anti-NSl protein antibody that binds ZIKV NS1 that is bound to the captured NS1 is detected by any appropriate method. Conditions for performing ELISA assays are well-known in the art. In a preferred embodiment, the antibody of the invention is strep-tagged and it is detected with an anti-strep tagged antibody. The amount of NS1 protein in the sample may then be measured through a calibration curve. In this preferred embodiment, the single variable domain antibody, heavy-chain antibody or other polypeptide of the invention serves as the capture antibody. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

Any other anti-NSl antibody, (that is cross-reactive NS1 antibody or that is not cross-reactive to NS1 proteins from different flavivirus) can be used as the detection or capture antibody, in combination with the single variable domain antibody, heavy-chain antibody or other polypeptide of the invention, so long as it binds ZIKV NS1. In one embodiment, an anti-NSl antibody that is cross-reactive to NS1 proteins from different flavivirus is used for capture. In one embodiment, an anti-NSl antibody that is not cross-reactive to NS1 proteins from different flavivirus is used for detection, so long as it binds ZIKV NS1. In one embodiment, the capture antibody is anti-NSl 17A12 mAb, previously described^{15 16}. In one embodiment, the capture antibody is anti-NSl mAh C23-21. In one embodiment, the capture antibody is a monoclonal or a polyclonal antibody. Any other anti-NSl antibody, (that is cross-reactive NS1 antibody or that is not cross-reactive to NS 1 proteins from different flavivirus) can be used as the detection antibody, so long as it binds ZIKV NS1. In one embodiment, an anti-NSl antibody that is cross-reactive to NS1 proteins from different flavivirus is used for detection. In one embodiment, an anti-NSl antibody that is not cross reactive to NS1 proteins from different flavivirus is used for detection, so long as it binds ZIKV NS1. In one embodiment, the detection antibody is anti-NSl 17A12 mAb, previously described^{15 16}. In one embodiment, the detection antibody is anti-NSl mAb C23-21. In one embodiment, the capture antibody is a monoclonal or a polyclonal antibody.

In some embodiments, the single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention is the capture antibody, and the non-specific/cross-reactive anti-NSl antibody (which binds nonspecifically to NS1 protein from various flavivirus) is the detection antibody. As described above, in some embodiments, the capture antibody preferentially binds the NS1 protein from the ZIKA Virus (ZIKV) over NS1 from other flavivirus. In some embodiments, the other flavivirus is one or more of DENV, WNV, YFV, Tick-borne encephalitis virus, and Japanese encephalitis virus.

In some embodiments, the detection methods that use the single variable domain antibody, heavy- chain antibody, or other polypeptide of the invention are quantitative. A quantitative method refers to any means of measuring an amount of NS1 protein present in a sample by using an single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention. In other embodiments, the detection methods are qualitative. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure. The invention also provides kits (i.e., a packaged combination of reagents in predetermined amounts) comprising one or more anti-NSl single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention that can be used for the detection and/or diagnostic methods of the invention. In one embodiment, the present invention is also directed to commercial kits for the detection and diagnosis of ZIKV infection (as early as DO to D5-7)). The kit can be in any configuration well known to those of ordinary skill in the art and is useful for performing one or more of the methods described herein for the detection of NS1 protein, as a surrogate for the presence of the ZIKV infection. The kits are convenient in that they supply many if not all of the essential reagents for conducting an assay for the detection of NS1 in a biological sample. In addition, the assay is preferably performed simultaneously with a standard or multiple standards that are included in the kit, such as a predetermined amount of at least one NS1 protein, so that the results of the test can be quantitated or validated. In some embodiments, the kit contains reagents necessary for performing an ELISA in accordance with the methods of the present invention (such as the ELISA performed in Example below). Such kits can include, without limitation, one or more antibodies to NS1 protein, purified NS1 protein, a secondary antibody (e.g., a biotinylated secondary antibody), wash buffer, blocking buffer, a signal molecule (such as, but not limited to Streptavidin-HRP), substrate solution, and/or stop solution (such as sulfuric acid). In some embodiments, the assay (e.g. ELISA) is sensitive to only ZIKV NS1 and does not cross react with flavivirus NS1 protein. In some embodiments, the reagents contained in the kit can detect at least about 1 ng/mL ZIKV NS1 protein in the sample. In other embodiments, the reagents contained in the kit can detect at least about 10 ng/mL ZIKV NS1 protein in the sample. In some embodiments, the reagents contained in the kit can detect at least about 100 ng/mL ZIKV NS1 protein in the sample. In other embodiments, the reagents contained in the kit can detect at least about 1 pg/mL ZIKV NS1 protein in the sample. In some embodiments, the reagents contained in the kit can detect at least about 10 pg/mL ZIKV NS1 protein in the sample. In other embodiments, the reagents contained in the kit can detect at least about 100 pg/mL ZIKV NS1 protein in the sample. In the prefered embodiments, the kit comprises one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure.

In some embodiments, the kit comprises a single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention as a detection agent. In some embodiments, the kit comprises a single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention as a capture agent.

In some embodiments, the single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention is immobilized on a support (e.g., an insoluble substrate, such as a plate or slide made of glass, plastic or metal, a polymer-coated bead, a tube, or a ceramic or metal chip) that comprises immobilized (or otherwise deposited) one or more of the antibodies or other polypeptides of the invention. In some embodiments, the antibody or other polypeptide is conjugated to a bead. Several bead possibilities are described where the agents that can be linked/conjugated to the antibodies or other polypeptides of the invention are described. In some embodiments, the antibody or other polypeptide is labeled with a His-tag/agent or with a streptavidin-tag/agent.

In some embodiments, the antibody or other polypeptide of the invention is immobilized on a support (e.g., an insoluble substrate, such as a plate or slide made of glass, plastic or metal, a polymer-coated bead, a tube, or a ceramic or metal chip) that comprises immobilized (or otherwise deposited) one or more of the antibodies or other polypeptides of the invention. In some embodiments, the antibody or other polypeptide is conjugated to a bead. Several bead possibilities are described where the agents that can be linked/conjugated to the antibodies or other polypeptides of the invention are described. In some embodiments, the antibody or other polypeptide is labeled with a His-tag/agent or with a streptavidin-tag/agent.

In some embodiments, the assay can detect at least about 1 ng/mL ZIKV NS1 protein in the sample. In other embodiments, the assay can detect at least about 10 ng/mL ZIKV NS1 protein in the sample. In some embodiments, the assay can detect at least about 100 ng/mL ZIKV NS1 protein in the sample. In other embodiments, the assay can detect at least about 1 pg/mL ZIKV NS1 protein in the sample. In some embodiments, the assay can detect at least about 10 pg/mL ZIKV NS1 protein in the sample. In other embodiments, the assay can detect at least about 100 pg/mL ZIKV NS1 protein in the sample. In some embodiments, the assay/detection method can detect from 1 ng/mL to 300 ng/mL ZIKV NS1 protein.

In one embodiment, the single variable domain antibody, heavy-chain antibody, or other polypeptide of the invention can be used in the early diagnosis of a ZIKAV infection (DO to D5-7) via its detection of ZIKAV NS1. In one embodiment, the single variable domain antibody, heavy- chain antibody, or other polypeptide of the invention can be used in the early diagnosis of a ZIKAV infection (DO to D5-7) via its detection of ZIKAV NS1 in a biological sample. In some of these embodiments, the biological sample comprises blood. In some of these embodiments, the biological sample comprises serum. In the prefered embodiments, the method uses one or more of the nanobodies/VHH whose CDRs are described elsewhere in this disclosure. In a preferred embodiment, the method uses the antibody NS 1-21.

The invention is also related to a companion diagnostic assay for the selection of a patient for specific treatment of a ZIKA virus infection, wherein the assay comprises:

(i) performing a method as described above to detect ZIKV in a biological sample of the patient before treatment, and

By“compagnion diagnostic assay” is meant, according to the invention, a test that is carried out before treating a patient in order to determine if the patient will be responsive to said treatment. The ZIKV NS1 protein is used as a biomarker for the companion diagnostic test. The detection of ZIKV NS1 in the tested biological sample is indicative of the patient being suitable for a treatment against a ZIKA infection.

The presence of ZIKV NS1 in the sample is preferably determined by an in vitro immunoassay such as Western Blotting, immunoprecipitation, immunocytochemistry, immunohistochemistry, immunoelectron microscopy, radioimmunoassay, optical immunoassay, Enzyme-Linked ImmunoSpot (ELISPOT) assay, 2D gel electrophoresis, digital enzyme-linked immunosorbent assay (ELISA), or analog ELISA, such as enzyme multiplied immunoassay technique (EMIT), enzyme-linked immunosorbent assay (ELISA), IgM antibody capture ELISA (MAC ELISA), and microparticle enzyme immunoassay (MEIA); capillary electrophoresis immunoassays (CEIA); radioimmunoassays (RIA); immunoradiometric assays (IRMA); fluorescence polarization immunoassays (FPIA); and chemiluminescence assays (CL).

The invention also relates to the use of a single variable domain antibody, a heavy-chain antibody or a peptide as decribed above in an in vitro companion diagnostic assay for the selection of a patient for specific treatment of a ZIKA virus infection.

The invention also relates to the use of a single variable domain antibody, a heavy-chain antibody or a peptide as decribed above to calibrate an in vitro serologic test.

The invention also relates to the use of a single variable domain antibody, a heavy-chain antibody or a peptide as decribed above as a positive control reagent in an in vitro serologic test.The invention is also related to the use of an antibody or other polypeptide according to the invention for the preparation of a reagent to detect ZIKV NS1 protein in vitro or in vivo. The reagents are described elsewhere in this disclosure as the antibodies, compositions, labels, objects, etc. that are a part of the invention.

The invention is also related to the use of an antibody or other polypeptide according to the invention for the preparation of a reagent to diagnose ZIKV infection in vitro or in vivo.

The invention is also related to an article of manufacture (e.g., a kit as described above) for diagnostic use, comprising packaging material and a container comprising one or more of the antibodies or other polypeptides of any one of claims.

One embodiment is directed to the single variable domain antibody, heavy-chain antibody, or other polypetideof the invention for use in the detection of ZIKV.

One embodiment is directed to the single variable domain antibody, heavy-chain antibody, or other polypetideof the invention for use in the in vitro, in vivo or in situ detection of ZIKV.

One embodiment is directed to a nucleic acid according to the invention, for use in the manufacture of a reagent to use in the detection or diagnosis of ZIKV infection, preferably by ZIKV NS 1 protein detection.

One embodiment is directed to a single variable domain antibody, heavy-chain antibody, or other polypeptide according to the invention, for use in the manufacture of a reagent for use in the detection or diagnosis of ZIKV infection, preferably by ZIKV NS1 protein detection. One embodiment is directed to a product or process substantially as hereinbefore described with reference to any one of the Examples and to any one of the accompanying drawings.

It should also be understood that, unless clearly indicated to the contrary, in any methods claimed herein that include more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

In the claims, as well as in the specification above, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "composed of," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" shall be closed or semi-closed transitional phrases, respectively.

While several inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of examples only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

Examples

EXAMPLE 1: MATERIALS AND METHODS

1. Production, selection and purification of VHH/nanobodies 1.1. Antigen preparation and induction of a humoral immune response in alpaca

Recombinant Zika NS1 was produced as previously described for dengue NS1 ⁿ. Briefly, a synthetic gene coding for the ZIKV NS1 protein (Asian strain), which was codon optimized for Drosophila expression, was initially inserted into a modified pMT/BiP plasmid in frame with the BiP signal sequence encoding segment upstream and a segment containing the thrombin cleavage site downstream followed by two Strep-tag sequences separated by glycine-serine linkers (GGGS). The resulting plasmids were used to transfect Drosophila S2 cells together with the pCoPuro plasmid. Stable cell lines were selected and maintained in serum-free Insect-Xpress medium containing 7 pg/mL puromycin. Cells were grown at 28°C in Insect-Xpress medium containing antibiotics (1% penicillin/streptomycin) to about lxlO⁷ cells/mL and protein expression was induced with 4 mM CdC12 or alternatively with 500 mM CuS04. After 4 days, S2 cells supernatants were harvested, concentrated 10-fold by ultrafiltration and supplemented with 10 pg/mL avidin and 0.1 M Tris-HCl pH 8.0, clarified by filtration. The recombinant NS1 protein was purified by streptactin affinity chromatography according to the manufacturer’s instructions.

125pg of antigen was mixed with 250 mΐ of Freund complete adjuvant for the first immunization, and with 250 mΐ of Freund incomplete adjuvant for the following immunizations. One young adult female alpaca Pachamama ( Lama paces ) was immunized at days 0, 21 and 40 with the immunogen. The alpaca was bled at day 52. The immune response was monitored by titration of serum samples by ELISA on coated NS1. The bound alpaca antibodies were detected with polyclonal rabbit anti- alpaca IgGs (obtained by immunizing rabbits with alpaca IgGs isolated on protein A and protein G columns).

1.2. Library construction and panning

250 ml of blood of the immunized animals was collected at day 52 and the peripheral blood lymphocytes isolated by centrifugation on a Ficoll (Pharmacia) discontinuous gradient and stored at -80°C until further use. Total RNA and cDNA was obtained as previously described ¹² and DNA fragments encoding VHH domains amplified by PCR using CH2FORTA4 and VHBACKA6 primers, which anneal to the 3' and 5' flanking region of the VH genes, respectively. The amplified product was used as template in a second round of PCR using either the primers VHB ACKA4 and VHFOR36 ¹³. The primers were complementary to the 5' and 3' ends of the amplified product and incorporated Sfil and Not] restriction sites at the ends of the VHH genes. The PCR products were digested and ligated into phage expression vector pHENl. Phages were produced and isolated.

The library was panned against ZIKV NS1 protein containing a Streptag. For the first round of panning, Phage- VHHs were incubated with the protein (10 nM) for 1 hour at room temperature (RT). The complex phages-NSl were then trapped via the Streptag by magnetic streptactin beads (IBA, Goettingen, Germany) for 30 min. For the following round of pannings and to eliminate the cross- reacting phage- VHHs, phages were first incubated with Dengue NSl-Streptag (ImM) and the complexes phages-dengue NS1 were removed by the use of magnetic Streptactin beads. The remaining phage- VHHs were then incubated with ZIKV NS1 Streptag. Three rounds of counter selection were performed. Phage- VHHs clones were screened by standard EFISA procedures using an HRP/anti-M13 monoclonal antibody conjugate (GE Healthcare) for detection (see below).

1.3. Expression of VHHs

The coding sequence of the selected VHH/nanobodies in vector pHENl was sub-cloned into a bacterial expression vector pET23d containing a 6-Histidine tag using Ncol and Notl restriction sites. Transformed E. coli BF21 (DE3) FysS cells express VHH in the cytoplasm after overnight induction with IPTG (0.5 mM) at 16°C. Purified VHHs were isolated by IMAC from cytoplasmic extracts using Cobalt agarose beads (Jena bioscience, Jena, Germany), according to the manufacturer’s instructions. The VHHs were eluted in 50mM sodium phosphate, 300mM NaCl and 500mM imidazole buffer and dialyzed in PBS buffer containing 300 mM NaCl (PBS/NaCl). 1.4. ELISA

Streptactin microtiter plates (IBA, Goettingen, Germany) were coated by incubation overnight at 4°C with 1 pg/ml of ZIKV NSl-streptag or DENV NSl-streptag proteins. Plates were washed with 0.1% Tween 20 in PBS buffer (buffer A). VHHs were diluted in PBS containing 0.5% gelatin and 0.1% Tween 20 (buffer B). After lh incubation at 37°C, plates were washed again before adding a rabbit anti-His tag polyclonal antibody (eBiosciences) followed by peroxidase labeled goat anti rabbit immunoglobulins (Abeam). Peroxidase activity was quantified using OPD (o- phenylendiamine dihydrochloride, Dako) substrate according to the manufacturer's protocol.

A sandwich EFISA was performed to determine the specificity of nanobodies against NS1 from different proteins (Flavivirus NS1 protein pack, the Native Antigen company, Oxford UK). Microtiter plates (Nunc, Denmark) were coated during an overnight incubation at 4°C with 1 pg/ml of flavivirus-crossreactive anti-NSl 17A12 mAh diluted in PBS. Plates were washed with buffer A. A His-tagged NS1 protein diluted in buffer B was added at various concentrations. After lh incubation at 37°C, plates were washed again before adding the different strep-tagged VHHs diluted in buffer B. After lh incubation at 37°C, plates were washed again before adding respectively a home-made biotinylated anti-strep tag mAh C23-21 followed by peroxidase labeled streptavidin (Pierce) and a final incubation in OPD.

1.5. Antigen capture ELISA

Microtiter plates (Nunc, Denmark) were coated by an overnight incubation at 4°C with 1 pg/ml of flavivirus-crossreactive anti-NSl 6B8 or 17A12 mAbs diluted in PBS. Plates were washed with buffer A. A Strep-tagged NS1 protein diluted in buffer B was added at various concentrations. After lh incubation at 37°C, plates were washed again before adding the different VHHs diluted in buffer B. The VHH concentration used was deduced from preliminary ELISA calibrations. Subsequent steps were performed as described above.

1.6. Determination of dissociation constants

Binding affinity of VHHs was determined according to the method of Friguet et al (1985)¹⁴. Briefly, various concentrations of ZIKV-NS1 were incubated in solution overnight at 4°C with a defined quantity of VHHs until equilibrium was reached. The VHH concentration used was deduced from preliminary ELISA calibrations. Each mixture (100 pi) was transferred to a well of a microtiter plate previously coated with antigen and was incubated for 15 min at 4°C. After washing with buffer A, bound VHH were detected by the addition of rabbit anti-His tag polyclonal antibody, followed by b -galactosidase-conjugated goat anti- rabbit immunoglobulins. Subsequent steps were performed as described above. The Kds were estimated by slope measurement of the regression curve obtained by plotting the reciprocal of the fraction bound of VHH versus the reciprocal of the molar concentration of the antigen. Example 2: RESULTS

2.1. Development of nanobodies specific ofZika virus NS1

VHHs were amplified by PCR and cloned in vector pHEN 1. Subsequent transformations yielded one library of about 4,8xl0⁸ clones. VHHs displaying the best affinity were selected by phage display through 4 panning cycles with ZIKV-NS1 and counter-selected against dengue NS1 protein to remove the cross reactive VHH. 96 individual clones were tested by ELISA on ZIKV NS1 and DENV NS1 proteins. 31 clones were found to bind specifically to the ZIKV NS1 protein. These clones were sequenced and 7 different VHHs were found (FIGs. 1 & 2).

These VHH were subcloned in vector pET23 or in vector pASK IBA2 to allow a high level of expression of VHH with, respectively, a His-tag or a Streptavidin-tag. Yields of <1 mg/1 of bacterial culture were obtained. The single domain products were shown to be pure to homogeneity by SDS- PAGE (data not shown). Affinity measurements were performed by ELISA as described in Material and Methods and the different nanobodies showed a Kd in the nanomolar range (FIG.6). ELISA experiments were performed using either ZIKV NS1 or DENV NS1. First, Strep-tagged ZIKV NS1 and DENV NS1 were coated on a Streptactin-ELISA microtiter plate. FIG. 3 showed that the different His-tagged VHHs recognized only ZIKV NS1 and not DENV NS1. Then, NS1 originated from different flaviviruses; West Nile virus (WN), Yellow fever virus (YF), Tick borne encephalitis virus (TBE), and Japanese Encephalitis virus (JE) were used. These different proteins contained a His tag and Strep-tagged nanobodies were used for their detection. The presence of the VHH was revealed using a biotinylated anti-Streptag mAb. These VHHs showed no cross reactivity with NS1 from different flaviviruses (data not shown).

2.2. Development of the antigen capture ELIS As using these novel nanobodies

The sensitivity of the antigen capture ELISAs prepared with these 7 nanobodies was tested. Two mAbs mAb 17A12 and mAb 6B8 were used as capture antibodies. As shown in FIG. 4A and 4B, the different nanobodies detected Strep-tagged-ZIKV NS1 from 300ng/ml up to 4 ng/ml in the antigen capture ELISA. The best combination was mAb 17A12 as capture antibody and nanobody NS 1-21 for detection (FIG. 5). The detection limit is 4 ng/ml of NS1 equivalent to what was obtained with 2 mAbs.

References

All references cited above or below are herein incorporated by reference.

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2. Waggoner, J. J. & Pinsky, B. A. Zika Virus: Diagnostics for an Emerging Pandemic Threat. J. Clin. Microbiol. 54, 860-7 (2016).

3. Hermann, L. L. et al. Evaluation of a dengue NS1 antigen detection assay sensitivity and specificity for the diagnosis of acute dengue virus infection. PLoS Negl. Trop. Dis. 8, e3193 (2014). 4. Hunsperger, E. A. et al. Evaluation of commercially available diagnostic tests for the detection of dengue virus NS1 antigen and anti-dengue virus IgM antibody. PLoS Negl. Trop. Dis. 8, e3171 (2014).

5. Muller, D. A. & Young, P. R. The flavivirus NS1 protein: molecular and structural biology, immunology, role in pathogenesis and application as a diagnostic biomarker. Antiviral Res. 98, 192-208 (2013).

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8. Lafaye, P., Achour, I., England, P., Duyckaerts, C. & Rougeon, F. Single-domain antibodies recognize selectively small oligomeric forms of amyloid b, prevent Ab-induced neurotoxicity and inhibit fibril formation. Mol. Immunol. 46, (2009).

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13. Li, T. et al. Cell-penetrating anti-GFAP VHH and corresponding fluorescent fusion protein VHH-GFP spontaneously cross the blood-brain barrier and specifically recognize astrocytes:

Application to brain imaging. FASEB J. 26, (2012).

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Claims

1. A single variable domain antibody comprising three complementarity-determining regions CDR1, CDR2, and CDR3, wherein the three CDRs comprise the following sets of sequences: CDR1 (SGRTFSNY AMD Y AMG, SEQ ID NO: 1), CDR2 (AAISW, SEQ ID NO: 2), and CDR3 (AAGEV GAFY SD YDLYD Y, SEQ ID NO: 3); and/or

CDR1 (SGRTFSNY AMD Y AMG, SEQ ID NO: 1), CDR2 (ADSV, SEQ ID NO: 4), and CDR3 (AAGEV GAFY SD YDLYD Y, SEQ ID NO: 3).

2. A single variable domain antibody comprising from the N-terminus to the C-Terminus the amino acid sequence SGRTFSNY AMD YAMG (SEQ ID NO: 1), SGRTFSNY AMG (SEQ ID NO: 5), SGRTFYRNTMG (SEQ ID NO: 6), SGFTFSSYPMR (SEQ ID NO: 7), or SGRTFSAYAIG (SEQ ID NO: 8) (corresponding to CDR1), the amino acid sequence AAISWSGGSTYGADSV (SEQ ID NO: 9), A AISGGRT YTRY AN S V (SEQ ID NO: 10), AAISWSGHSTYSADSV (SEQ ID NO: 11), SAITWSGNSTPYADSV (SEQ ID NO: 12), AAISWSGDSTYPADSV (SEQ ID NO: 13), SIINSDGSSTYY ADSV (SEQ ID NO: 14), or AAISGGVVYTRY ADFV (SEQ ID NO: 15) (corresponding to CDR2), and the amino acid sequence AAGEVGAFYSDYDLYDY (SEQ ID NO: 3), SASQVGSGLAPTTRDRYAV (SEQ ID NO: 16), AAGPYMTAAPRTSSSYKY (SEQ ID NO: 17), ARGRGVSDPGGMD Y (SEQ ID NO: 18), or AAGQVGSGLAPTTRDRYVV (SEQ ID NO: 19) (corresponding to CDR3).

CDR1 ( SGRTFS NY AMD Y AMG , SEQ ID NO: 1), CDR2 (AAISWSGHSTYSADSV, SEQ ID NO: 11), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

CDR1 (SGRTFYRNTMG, SEQ ID NO: 6), CDR2 (SAITWSGNSTPYADSV, SEQ ID NO: 12), and CDR3 (AAGPYMTAAPRTSSSYKY, SEQ ID NO: 17); CDR1 (SGRTFSNYAMDYAMG, SEQ ID NO: 1), CDR2 (AAISWSGDSTYPADSV, SEQ ID NO: 13), and CDR3 (AAGEVGAFYSDYDLYDY, SEQ ID NO: 3);

CDR1 (SGFTFSSYPMR, SEQ ID NO: 7), CDR2 (SIINSDGSSTYYADSV, SEQ ID NO: 14), and CDR3 (ARGRGV SDPGGMD Y, SEQ ID NO: 18); or

CDR1 (SGRTFSAYAIG, SEQ ID NO: 8), CDR2 (AAISGGVVYTRYADFV, SEQ ID NO: 15), and CDR3 (AAGQVGSGLAPTTRDRYVV, SEQ ID NO: 19).

4. A heavy-chain antibody comprising a variable region (VHH), an hinge, and one or two constant regions (CH2 an CH3), wherein the variable region (VHH) comprises the sequence of the antibody of any one of claims 1 to 3.

5. A polypeptide comprising a single variable domain antibody comprising from the N- terminus to the C-Terminus the amino acid sequence SGRTFSNYAMDYAMG (SEQ ID NO: 1), SGRTFS NY AMG (SEQ ID NO: 5), SGRTFYRNTMG (SEQ ID NO: 6), SGFTFSSYPMR (SEQ ID NO: 7), or SGRTFSAYAIG (SEQ ID NO: 8) (corresponding to CDR1), the amino acid sequence AAISWSGGSTYGADSV (SEQ ID NO: 9), AAISGGRTYTRYANSV (SEQ ID NO: 10), AAIS WSGHSTY S ADS V (SEQ ID NO: 11), SAITWSGNSTPYADSV (SEQ ID NO: 12), AAISWSGDSTYPADSV (SEQ ID NO: 13), SIINSDGSSTYYADSV (SEQ ID NO: 14), or AAISGGVVYTRYADFV (SEQ ID NO: 15) (corresponding to CDR2), and the amino acid sequence AAGEVGAFY SDYDLYDY (SEQ ID NO: 3), SASQVGSGLAPTTRDRYAV (SEQ ID NO: 16), A AGP YMT A APRT S S S YKY (SEQ ID NO: 17), ARGRGV SDPGGMD Y (SEQ ID NO: 18), or AAGQVGSGLAPTTRDRYVV (SEQ ID NO: 19) (corresponding to CDR3).

6. A nucleic acid encoding any one of the single variable domain antibodies, heavy chain antibodies, or polypeptide as defined in any one of claims 1 to 5.

7. A genetic construct comprising a nucleic acid as defined in claim 6.

8. A recombinant host cell comprising a nucleic acid encoding one or more single variable domain antibodies, heavy chain antibodies or polypeptide as defined in any one of claims 1 to 5.

9. A composition comprising a single variable domain antibody, heavy-chain antibody or polypeptide as defined in any one of claims 1 to 5 and a pharmaceutically acceptable carrier.

10. A method of detecting ZIKV NS1 protein in a biological sample comprising (i) contacting the biological sample with a single variable domain antibody, heavy chain antibody or polypeptide as defined in any one of claims 1 to 5 under conditions permissive for binding of the antibody, heavy-chain antibody or polypeptide to ZIKV NS1 protein in the sample and (ii) detecting whether a complex is formed between the antibody, heavy-chain antibody or polypeptide and the ZIKV NS 1 protein in the biological sample, wherein detection of the formation of the complex indicates the presence of ZIKV NS1 protein in the sample.

11. A kit for detecting ZIKV NS1 protein in a sample comprising a single variable domain antibody, heavy-chain antibody or polypeptide as defined in any one of claims 1 to 5.

12. An article of manufacture (kit) for diagnostic use, comprising packaging material and a container comprising one or more of the single variable domain antibodies, heavy-chain antibodies or polypeptides as defined in any one of claims 1 to 5.

13. The single variable domain antibody, heavy-chain antibody or polypeptide as defined in any one of claims 1 to 5, for use in the in vitro detection of ZIKV NS1 protein.

14. A companion diagnostic assay for the selection of a patient for specific treatment of a ZIKA virus infection, wherein the assay comprises:

(i) performing a method as defined in claim 10 to detect ZIKV in a biological sample of the patient before treatment, and

15. The use of a single variable domain antibody, a heavy-chain antibody or a peptide as defined in any one of claims 1 to 5 to calibrate an in vitro serologic test or as a positive control reagent in an in vitro serologic test.