Patent Application
20220281959
The present invention relates to antibodies and their use. The invention particularly relates to antibodies against a particular domain of gp41, pharmaceutical compositions or kits or any device comprising the same, as well as the uses thereof. The invention is particularly useful for treating (e.g., curing or preventing), detecting or monitoring AIDS in a subject, either, alone or in combination with other treatments/agents.
It has been documented by the inventors that sPLA2-GIB is involved in the inactivation of CD4 T cells in HIV infected patients (see WO2015/097140). It was proposed and documented by the inventor that sPLA2-GIB modulators are effective for treating diseases in mammal, e.g., disorders associated with an immune deficiency.
Continuing their research, applicant found that the effect of sPLA2-GIB can be mediated and/or amplified by cofactors present in diseased subjects, and that such cofactors act through a gC1q receptor at the surface of T cells (see PCT/EP2019/054686). It was proposed and documented by the inventors that modulators of such cofactors are effective for treating diseases in mammal, e.g., disorders associated with an immune deficiency. In relation to HIV viremic patients, it was more specifically disclosed that gp41 acts as a cofactor that increases sPLA2-GIB inhibitory effect on human CD4 T cells. It was also shown that gp41-derived PEP3 peptide alone also increases sPLA2-GIB activity, suggesting that PEP3 gp41 sequence is a key domain for gp41 cofactor activity.
The present invention now discloses novel anti-gp41 antibodies that are specific of the PEP3 sequence. The present invention relates to such antibodies, variants thereof, their manufacture, compositions or devices containing the same, and the uses thereof e.g., for detecting, monitoring or treating HIV disorders.
More specifically, the invention provides antibodies and variants thereof selected for their binding on gp41 protein, more specifically on the PEP3 domain of gp41. The invention discloses the sequence of said antibodies and their functional properties, such as e.g., their specificity for gp41 relatively to gp120, their ability to reduce the inhibitory activity of HIV viremic patient plasma on CD4 T cells, and/or their ability to quantify gp41 products in the plasma of HIV viremic patients.
Altogether these antibodies can thus be used to follow gp41 concentration in the plasma of HIV patients or any other sample and thus to predict the severity of HIV disease or the outcome of HIV viremic patients.
The invention generally relates to novel antibodies and the uses thereof. The invention particularly discloses anti-PEP3 antibodies that can be used to inhibit gp41 cofactor activity in HIV viremic patients. In addition, these antibodies can be used to quantify gp41 in the plasma of HIV viremic patients and to follow the outcome of gp41 concentration during antiretroviral treatment.
As used herein, the term “gp41” designates the glycoprotein of essentially 41 kDa encoded by a HIV virus. The sequence of gp41 is available on Genbank, e.g., No. AAC31817.1. The amino acid sequence of an exemplary gp41 protein is shown as SEQ ID NO: 1. Amino acids 97 to 111 of SEQ ID NO: 1 (SEQ ID NO: 2) represent a domain of gp41 designated PEP3 sequence or domain or peptide.
The term gp41 designates any form of the protein, including any natural variants thereof, such as variants resulting from polymorphism or splicing. The term “gp41” designates typically a protein comprising the sequence of SEQ ID NO: 1 or any natural variants thereof, such as variants resulting from polymorphism or splicing.
Generally, the term “antibody” designates any immunoglobulin-type molecule comprising heavy and light chains. Typical antibodies possess the basic monomeric “H2L2” structure consisting of 2 Heavy and 2 Light chains. Each heavy chain is paired with a light chain. Heavy and light chains comprise a “variable region” or “variable domain”. The variable domain of the heavy chain may be referred to as “VH.” The variable domain of the light chain may be referred to as “VL.” These domains are generally the most variable parts of an antibody and contain the antigen-binding sites. A light or heavy chain variable region (VL or VH) consists of a framework region interrupted by three hypervariable regions referred to as “complementarity determining regions” or “CDRs”.
Antibody “fragments” designate any portion of an antibody that confers antigen binding. Fragments typically designate Fab, Fab′2, ScFv, nanobodies, or CDR.
Antibody “variant”, as used herein, refers to an antibody which retains the antigenic specificity of a reference antibody but wherein one or more amino acid residues are (e.g., chemically, or biologically) modified, typically to improve its properties. Examples of such chemical modifications include, e.g. by alkylation, PEGylation, acylation, ester or amide formation, and the like. In particular, a variant is an antibody as disclosed herein that is modified to contain one or more additional non-proteinaceous moieties such as water-soluble polymers. Examples of water-soluble polymers include, but are not limited to, PEG, copolymers of ethylene glycol/propylene glycol, carboxymethylcellulose, dextran and polyvinyl alcohol.
Variants may also be generated to increase or decrease the extent to which the antibody is glycosylated. Addition or deletion of glycosylation sites to an antibody may be conveniently accomplished by altering the amino acid sequence such that one or more glycosylation sites is created or removed. Where the antibody comprises an Fc region, the carbohydrate attached thereto may be altered. Native antibodies produced by mammalian cells typically comprise a branched, biantennary oligosaccharide that is generally attached by an N-linkage to Asn297 of the CH2 domain of the Fc region (see e.g., Wright et al. TIBTECH, 1997, 15:26-32). The oligosaccharide may include various carbohydrates, e.g., mannose, N-acetyl glucosamine (GlcNAc), galactose, and sialic acid, as well as a fucose attached to a GlcNAc in the “stem” of the biantennary oligosaccharide structure. In some embodiments, modifications of the oligosaccharide in an antibody of the invention may be made in order to create antibody variants with certain improved properties.
In one embodiment, the variant has a modified Fc region in order to alter ADCC (through a modulation of FcgammaRIII binding).
In one embodiment, antibody variants are provided having a carbohydrate structure that lacks fucose attached (directly or indirectly) to an Fc region. For example, the amount of fucose in such antibody may be from 1% to 80%, from 1% to 65%, from 5% to 65% or from 20% to 40%). The amount of fucose is determined by calculating the average amount of fucose within the sugar chain at Asn297, relative to the sum of all glycostructures attached to Asn 297 (e. g. complex, hybrid and high mannose structures) as measured by MALDI-TOF mass spectrometry. Asn297 refers to the asparagine residue located at about position 297 in the Fc region (Eu numbering of Fc region residues); however, Asn297 may also be located about 3 amino acids upstream or downstream of position 297, i.e., between positions 294 and 300, due to minor sequence variations in antibodies. Examples of publications related to “defucosylated” or “fucose-deficient” antibody variants include, but are not limited to, Okazaki et al. J. Mol. Biol. 336: 1239-1249 (2004) and Yamane-Ohnuki N, Satoh M. mAbs. 2009; 1:230-236. Examples of cell lines capable of producing defucosylated antibodies include Led 3 CHO cells deficient in protein fucosylation (Ripka et al. Arch. Biochem. Biophys. 249:533-545 (1986)), and knockout cell lines, such as alpha-1,6-fucosyltransferase gene, FUT8, knockout CHO cells (see, e.g., Yamane-Ohnuki et al. Biotech. Bioeng. 87: 614 (2004); Kanda, Y. et al., Biotechnol. Bioeng., 94(4):680-688 (2006)).
In certain embodiments, it may be desirable to create cysteine engineered antibodies, e.g., “thioMAbs,” in which one or more residues of an antibody are substituted with cysteine residues. In particular embodiments, the substituted residues occur at accessible sites of the antibody. By substituting those residues with cysteine, reactive thiol groups are thereby positioned at accessible sites of the antibody and may be used to conjugate the antibody to other moieties, such as drug moieties or linker-drug moieties, to create an immunoconjugate, as described further herein. In certain embodiments, any one or more of the following residues may be substituted with cysteine: V205 (Kabat numbering) of the light chain; A118 (EU numbering) of the heavy chain; and S400 (EU numbering) of the heavy chain Fc region. Cysteine engineered antibodies may be generated as described, e.g., in U.S. Pat. No. 7,521,541.
The term “variants” also includes immunoconjugates comprising an antibody as defined above conjugated to one or more heterologous molecule(s), including but not limited to a cytotoxic agent, a detectable moiety such as a fluorescent moiety, a diagnostic radioisotope or an imaging agent; or to a solid support, such as agarose beads or the like. Examples of cytotoxic agents include, but are not limited to chemotherapeutic agents or drugs, growth inhibitory agents, toxins (e.g., protein toxins, enzymatically active toxins of bacterial, fungal, plant, or animal origin, or fragments thereof), or radioactive isotopes. Conjugates of an antibody and cytotoxic agent may be made using a variety of bifunctional protein coupling agents well known by the skilled person. The linker may be a “cleavable linker” facilitating release of a cytotoxic drug in the cell. For example, an acid-labile linker, peptidase-sensitive linker, photolabile linker, dimethyl linker or disulfide-containing linker (Chari et al., Cancer Res. 52: 127-131 (1992)) may be used. Derivatives may also be bispecific antibodies. Particular variants are labelled antibodies, carrying a label (such as a marker, tracer, tag) allowing detection or capture of an antibody. Examples of such variants include fusion molecules formed by covalent or non-covalent association of the antibody with one or more proteins or peptides, such as a reporter peptide allowing the detection, or the quantification of the fusion molecule. In some embodiments, antibody variants of the invention can be engineered, such as biotinylated, to be detectable and/or quantifiable. Variants also include humanized antibodies.
In preferred embodiments, antibodies and fragments and variants of the invention are isolated. An “isolated” antibody is one which has been separated from a component of its natural environment. In particular, the antibody may be purified to greater than 95% or 99% purity as determined by, for example, electrophoretic (e.g., SDS-PAGE, isoelectric focusing (IEF), capillary electrophoresis) or chromatographic (e.g., ion exchange or reverse phase HPLC). For review of methods for assessment of antibody purity, see, e.g. Flatman et al., J. Chromatogr. B 848:79-87 (2007).
An antibody is “selective” for an antigen, or “selectively binds” an antigen when such antibody exhibits preferential binding to said antigen as compared to other molecules. Selectivity can be determined by competitive ELISA or Biacore assays. The difference in affinity/avidity that marks selectivity can be any detectable preference, such as e.g., a ratio of more than 1:1.1, or more than about 1:5, 1:10, 1:100, 1:1000 or more.
“gC1qR” or “gC1q receptor” designates the receptor for complement C1q at the surface of cells, particularly of CD4 T cells, especially the human form of said receptor. gC1qR is also known as C1q binding protein (C1QBP), ASF/SF2-associated protein p32 (SF2P32); Glycoprotein gC1qBP; Hyaluronan-binding protein 1 (HABP1); Mitochondrial matrix protein p32; gC1q-R protein; p33; C1qBP and GC1QBP. The amino acid sequence of the receptor was disclosed in the art. An exemplary amino acid sequence of human gC1qR is depicted as SEQ ID NO: 65.
The term gC1qR designates any receptor of SEQ ID NO: 65 (accession number UniProtKB/Swiss-Prot: Q07021.1) above, as well as processed forms and variants thereof. Variants include naturally-occurring variants having e.g., at least 90% amino acid sequence identity to SEQ ID NO: 65.
Applicant has previously documented that gp41 binds Gc1qR, which triggers a signaling pathway that results in exocytosis of intracellular vesicles. Inhibiting binding of gp41 to gC1qR designates any level of inhibition, preferably at least 10%, at least 20%, at least 30%, at least 40%, or at least 50% reduction of such binding. Such activity can be verified in vitro using methods known per se in the art.
Anti-PEP3 Antibodies
In a particular aspect, the invention relates to anti-gp41 antibodies, variants or fragments thereof. Such antibodies were generated by immunization with a PEP3 peptide and subsequently selected based on their capacity to bind gp41 and/or the PEP3 domain. The antibodies were further selected for their capacity to block gp41 binding to C1qR, and/or to effectively quantify reactive gp41 in biological samples. The amino acid sequences of the heavy and light chains of antibodies of the invention were determined, allowing recombinant production thereof and generation of variants thereof. Upon testing, it was confirmed these antibodies are able to bind gp41 and/or PEP3. It was also found antibodies of the invention effectively inhibit the inhibitory effect of HIV viremic plasma on CD4 T cells. These antibodies thus exhibit remarkable properties for therapeutic and diagnostic uses.
The amino acid sequences of the light and heavy chains variable regions of these antibodies are provided in SEQ ID NOs: 3-14 (see also the FIG). The CDR domains of each variable region are also identified and provided as SEQ ID Nos: 15-50.
In a particular aspect, the invention relates to a gp41-binding antibody comprising a CDR region consisting, or consisting essentially, of a sequence selected from anyone of SEQ ID Nos: 15-50.
In a further particular embodiment, the invention relates to a monoclonal antibody comprising a light chain variable region, wherein the light chain variable region comprises (i) a CDR-L1 consisting, or consisting essentially, of a selected from SEQ ID NOs: 15, 21, 27, 33, 39, or 45, and/or (ii) a CDR-L2 consisting, or consisting essentially, of a selected from SEQ ID NOs: 16, 22, 28, 34, 40, or 46, and/or (iii) a CDR-L3 consisting, or consisting essentially, of a selected from SEQ ID NOs: 17, 23, 29, 35, 41, or 47.
In a more specific embodiment, the light chain variable region comprises a CDR-L1, a CDR-L2 and a CDR-L3 as follows:
In a further particular embodiment, the invention relates to a monoclonal antibody comprising a heavy chain variable region, wherein the heavy chain variable region comprises (i) a CDR-H1 consisting, or consisting essentially, of a selected from SEQ ID NOs: 18, 24, 30, 36, 42, or 48, and/or (ii) a CDR-H2 consisting, or consisting essentially, of a selected from SEQ ID NOs: 19, 25, 31, 37, 43, or 49, and/or (iii) a CDR-H3 consisting, or consisting essentially, of a selected from SEQ ID NOs: 20, 26, 32, 38, 44, or 50.
In a more specific embodiment, the heavy chain variable region comprises a CDR-H1, a CDR-H2 and a CDR-H3 as follows:
In a further particular embodiment, the invention relates to a monoclonal antibody comprising a light and a heavy chain variable region as defined above. More specifically, particular monoclonal antibodies of the invention comprise:
In a more particular embodiment, the invention relates to a monoclonal antibody comprising the light chain variable region consisting, or consisting essentially, of a sequence selected from SEQ ID NOs: 3, 5, 7, 9, 11 and 13 and/or a heavy chain variable region consisting, or consisting essentially, of a sequence selected from SEQ ID NOs: 4, 6, 8, 10, 12, and 14.
In a more particular embodiment, the invention relates to a monoclonal antibody comprising a light chain variable region and a heavy chain variable region as follows:
Specific examples of antibodies of the invention are antibodies 4G1, 8D5, 3A2, 15B4, 5E12, and 9B12.
As discussed above and illustrated in the examples, antibodies of the invention bind gp41 and/or PEP3, and/or inhibit binding of gp41 to gC1qR, and/or inhibit the inhibitory effect of HIV viremic plasma on CD4 T cells.
In another embodiment, the invention relates to an anti-gp41 antibody that binds an epitope of gp41 comprising one or more amino acid residues of SEQ ID NO: 63 or 64.
Nucleic Acids. Vectors and Host Cells
The invention also relates to nucleic acids encoding an antibody or fragment as defined above, as well as cloning or expression vectors containing such nucleic acids, and recombinant host cells.
In another aspect, the present invention concerns nucleic acid molecules encoding an antibody of the invention, or a nucleic acid complementary to said encoding sequence. Preferably, the nucleic acid is an isolated or purified nucleic acid.
The nucleic acid can be DNA (cDNA or gDNA), RNA, or a mixture thereof. It can be in single stranded form or in duplex form or a mixture of the two. It can comprise modified nucleotides, comprising for example a modified bond, a modified purine or pyrimidine base, or a modified sugar. It can be prepared by any method known to one skilled in the art, including chemical synthesis, recombination, and mutagenesis. The nucleic acid according to the invention may be deduced from the sequence of the antibody according to the invention and codon usage may be adapted according to the host cell in which the nucleic acid shall be transcribed. These steps may be carried out according to methods well known to one of skill in the art and some of which are described in the reference manual Sambrook et al. (Sambrook J, Russell D (2001) Molecular cloning: a laboratory manual, Third Edition Cold Spring Harbor).
The nucleic acid of the invention may encode an amino acid sequence comprising the light chain and/or an amino acid sequence comprising the heavy chain of the antibody, or may be complementary to such encoding sequence.
Specific examples of such nucleic acid sequences include the sequences comprising anyone of SEQ ID NOs: 51-62, and the complementary sequence thereto.
The present invention further provides a vector comprising a nucleic acid of the invention. Optionally, the vector may comprise several nucleic acids of the invention. In particular, the vector may comprise a nucleic acid of the invention operably linked to a regulatory region, i.e. a region comprising one or more control sequences. Optionally, the vector may comprise several nucleic acids of the invention operably linked to several regulatory regions.
The term “control sequences” means nucleic acid sequences necessary for expression of a coding region. Control sequences may be endogenous or heterologous. Well-known control sequences and currently used by the person skilled in the art will be preferred. Such control sequences include, but are not limited to, promoter, signal peptide sequence and transcription terminator.
The term “operably linked” means a configuration in which a control sequence is placed at an appropriate position relative to a coding sequence, in such a way that the control sequence directs expression of the coding region.
The present invention further relates to the use of a nucleic acid or vector according to the invention to transform, transfect or transduce a host cell.
The present invention also provides a host cell comprising one or several nucleic acids of the invention and/or one or several vectors of the invention.
The term “host cell” also encompasses any progeny of a parent host cell that is not identical to the parent host cell due to mutations that occur during replication. Suitable host cells for cloning or expression of antibody-encoding vectors include prokaryotic or eukaryotic cells described herein.
For example, antibodies may be produced in bacteria, in particular when glycosylation and Fc effector function are not needed. For expression of antibody fragments and polypeptides in bacteria, see, e.g., U.S. Pat. Nos. 5,648,237, 5,789,199, and 5,840,523. (See also Charlton, Methods in Molecular Biology, Vol. 248 (B. K. C. Lo, ed., Humana Press, Totowa, N.J., 2003), pp. 245-254, describing expression of antibody fragments in E. coli.) After expression, the antibody may be isolated from the bacterial cell lysate in a soluble fraction and can be further purified.
In addition to prokaryotes, eukaryotic microbes such as filamentous fungi or yeast are suitable cloning or expression hosts for antibody-encoding vectors, including fungi and yeast strains whose glycosylation pathways have been “humanized,” resulting in the production of an antibody with a partially or fully human glycosylation pattern. See Gerngross, Nat. Biotech. 22: 1409-1414 (2004), and Li et al., Nat. Biotech. 24:210-215 (2006).
Suitable host cells for the expression of glycosylated antibody are also derived from multicellular organisms (invertebrates and vertebrates). Examples of invertebrate cells include plant and insect cells. Numerous baculoviral strains have been identified which may be used in conjunction with insect cells, particularly for transfection of Spodoptera frugiperda cells. Plant cell cultures can also be utilized as hosts. See, e.g., U.S. Pat. Nos. 5,959,177, 6,040,498, 6,420,548, 7,125,978, and 6,417,429.
Vertebrate cells may also be used as hosts. For example, mammalian cell lines that are adapted to grow in suspension may be useful. Other examples of useful mammalian host cell lines are monkey kidney CV1 line transformed by SV40 (COS-7); human embryonic kidney line (293 or 293 cells as described, e.g., in Graham et al., J. Gen Virol. 36:59 (1977)); baby hamster kidney cells (BHK); mouse Sertoli cells (TM4 cells as described, e.g., in Mather, Biol. Reprod. 23:243-251 (1980)); monkey kidney cells (CV1); African green monkey kidney cells (VERO-76); human cervical carcinoma cells (HELA); canine kidney cells (MDCK; buffalo rat liver cells (BRL 3A); human lung cells (W138); human liver cells (Hep G2); mouse mammary tumor (MMT 060562); TRI cells, as described, e.g., in Mather et al., Annals N. Y. Acad. Sci. 383:44-68 (1982); MRC 5 cells; and FS4 cells. Other useful mammalian host cell lines include Chinese hamster ovary (CHO) cells, including DHFR− CHO cells (Urlaub et al., Proc. Natl. Acad. Sci. USA 77:4216 (1980)); and myeloma cell lines such as Y0, NS0 and Sp2/0. For a review of certain mammalian host cell lines suitable for antibody production, see, e.g., Yazaki and Wu, Methods in Molecular Biology, Vol. 248 (B.K.C. Lo, ed., Humana Press, Totowa, N.J.), pp. 255-268 (2003).
The present invention also concerns a method for producing an antibody of the invention, comprising culturing a host cell comprising a nucleic acid of the invention or a vector of the invention, as provided above, under conditions suitable for expression of the antibody, and optionally recovering the antibody from the host cell or from the host cell culture medium. Optionally, the recovered antibody may be further purified or isolated. Suitable media, culture conditions and production method are well-known by the skilled person and can be easily chosen according to the host cell and the antibody to be produced.
Pharmaceutical and Diagnostic Compositions
The present invention further relates to pharmaceutical or diagnostic compositions comprising an antibody, a nucleic acid, a vector or a host cell of the invention. The composition may comprise one or several antibodies of the invention, one or several nucleic acids of the invention and/or one or several vectors of the invention and/or one or several host cells of the invention. Preferably, the composition comprises one or several antibodies of the invention.
Pharmaceutical compositions comprise an antibody of the invention and any suitable excipient. Typically, the antibody has the desired degree of purity and is mixed with optional physiologically acceptable carriers, vehicle or stabilizers (Remington: The Science and Practice of Pharmacy 20th edition (2000)), in the form of e.g., aqueous solutions, lyophilized or other dried formulations.
Acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations employed, and include, but are not limited to, buffering agents, stabilizing agents, preservatives, isotonifiers, non-ionic detergents, antioxidants and other miscellaneous additives.
Buffering agents help to maintain the pH in the range which approximates physiological conditions. They are preferably present at concentration ranging from about 1 mM to about 50 mM. Suitable buffering agents for use with the present invention include, but are not limited to, both organic and inorganic acids and salts thereof such as citrate, succinate, tartrate, fumarate, gluconate, oxalate, lactate and acetate buffers, as well as phosphate buffers, histidine buffers and trimethylamine salts such as Tris.
Preservatives may be added to retard microbial growth, and may be added in amounts ranging from 0.2%-1% (w/v). Suitable preservatives for use with the present invention include, but are not limited to, phenol, butyl or benzyl alcohol; meta-cresol; alkyl parabens such as methyl or propyl paraben; octadecyldimethylbenzyl ammonium chloride, benzalkonium halides (e.g., chloride, bromide, iodide); hexamethonium or benzethonium chloride; catechol; resorcinol; cyclohexanol; and 3-pentanol.
Isotonifiers may be added to ensure isotonicity of liquid compositions of the present invention and include polhydric sugar alcohols, preferably trihydric or higher sugar alcohols, such as glycerin, erythritol, arabitol, xylitol, sorbitol and mannitol.
Stabilizing agents refer to a broad category of excipients which can range in function from a bulking agent to an additive which solubilizes the therapeutic agent or helps to prevent denaturation or adherence to the container wall. Typical stabilizers can be polyhydric sugar alcohols (enumerated above); amino acids such as arginine, lysine, glycine, glutamine, asparagine, histidine, alanine, ornithine, L-leucine, 2-phenylalanine, glutamic acid, threonine, etc., organic sugars or sugar alcohols, such as lactose, trehalose, stachyose, mannitol, sorbitol, xylitol, ribitol, myoinisitol, galactitol, glycerol and the like, including cyclitols such as inositol; polyethylene glycol; amino acid polymers; sulfur containing reducing agents, such as urea, glutathione, thioctic acid, sodium thioglycolate, thioglycerol, .alpha.-monothioglycerol and sodium thio sulfate; low molecular weight polypeptides (i.e. <10 residues); proteins such as human serum albumin, bovine serum albumin, gelatin or immunoglobulins; hydrophylic polymers, such as polyvinylpyrrolidone monosaccharides, such as xylose, mannose, fructose, glucose; disaccharides such as lactose, maltose, sucrose and trisaccacharides such as raffinose; polysaccharides such as dextran. Stabilizers may be present in the range from 0.1 to 10,000 weights per part of weight therapeutic agent.
Non-ionic surfactants or detergents (also known as “wetting agents”) may be added to help solubilize the therapeutic agent as well as to protect the therapeutic protein against agitation-induced aggregation. Suitable non-ionic surfactants include, but are not limited to, polysorbates (20, 80, etc.), polyoxamers (184, 188 etc.), PLURONICS™, polyols, polyoxyethylene sorbitan monoethers (TWEEN™-20, TWEEN™-80, etc.). Non-ionic surfactants may be present in a range of about 0.05 mg/ml to about 1.0 mg/ml, preferably about 0.07 mg/ml to about 0.2 mg/ml.
Additional miscellaneous excipients include, but are not limited to, bulking agents, (e.g. starch), chelating agents (e.g. EDTA), antioxidants (e.g., ascorbic acid, methionine, vitamin E), and cosolvents.
The active ingredients may also be entrapped in microcapsule prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsule and poly-(methylmethacylate) microcapsule, respectively, in colloidal drug delivery systems (for example, liposomes, albumin micropheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are disclosed in Remington: The Science and Practice of Pharmacy 20th edition (2000).
The pharmaceutical compositions of the invention can be formulated for a topical, oral, parenteral, intranasal, intravenous, intramuscular, subcutaneous or intraocular administration and the like.
Preferably, the pharmaceutical formulation is a formulation capable of being injected. These may be in particular isotonic, sterile, saline solutions (monosodium or disodium phosphate, sodium, potassium, calcium or magnesium chloride and the like or mixtures of such salts), or dry, especially freeze-dried compositions which upon addition, depending on the case, of sterilized water or physiological saline, permit the constitution of injectable solutions.
Sterile injectable solutions may be prepared by incorporating the active compounds in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filtered sterilization. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum-drying and freeze-drying techniques which yield a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof.
In addition to the compositions formulated for parenteral administration, such as intravenous or intramuscular injection, other pharmaceutically acceptable forms include, e.g. tablets or other solids for oral administration; time release capsules; and any other form currently used.
The pharmaceutical composition of the invention may comprise one or several antibodies of the invention.
The pharmaceutical composition may further comprise one or several additional active compounds. Examples of additional active compounds include, but are not limited to, chemotherapeutic drug, antibiotics, antiparasitic agents, antifungal agents or antiviral agents.
The amount of antibody of the invention which will be effective in the treatment of a particular disorder or condition will depend on the nature of the disorder or condition, and can be determined by standard clinical techniques. In a preferred embodiment, each dose may range from about 0.1 mg to about 25 mg per kilogram of body weight of antibody, or more preferably, from about 1 mg to about 10 mg per kilogram body weight. The dosing schedule for administration may vary form once a month to daily depending on a number of clinical factors, including the type of disease, severity of disease, and the subject's sensitivity to the therapeutic agent.
Methods of Detection, Dosage, Diagnosis
In a further aspect, the present invention relates to a method for detecting or quantifying gp41 using an antibody or fragment or variant as defined above. The method can be used or implemented for monitoring the severity or progression of HIV infection in a subject, as well as for predicting the outcome of such infection or determining the optimal treatment.
In a particular embodiment, the method comprises a) providing a sample, and b) detecting the presence or amount of gp41 protein in the sample using an antibody or fragment as defined above.
Typically, the detecting step b) comprises the steps of (i) contacting the sample, or biological replicates of the sample, with anyone of the monoclonal antibodies or fragments or variants thereof herein described, and (ii) detecting the presence of an antibody:antigen complex formed in step (i).
Detecting the presence of an antibody: antigen complex can be performed by any technique well known per se by the skilled person and extensively described in the literature. Typically, detection can be performed with a second antibody against gp41, preferably that binds an epitope distinct (and remote) from that of the first capture antibody. Alternatively, the capture antibody may be labelled and the detection step may comprise measuring the amount of label in the reaction, typically after removing unbound antibodies.
The antibody may be immobilized on a surface or particle, or not. The reaction can be performed in any appropriate support or container, such as microplate, on a chip, in a bottle, etc. Also, in a particular embodiment, the detecting step (ii) utilizes a labelled antibody, such as an antibody conjugated to a reporting group or engineered to be detectable, more preferentially said antibody is biotinylated.
The method may be used with any sample such as any biological sample, such as a serum sample, a plasma sample, whole blood, biological fluids, etc. In more particular embodiments, the sample used is obtained from a subject. The sample may be treated prior to detection, such as by dilution, concentration, enrichment, etc. It may be lyophilized, sterilized, frozen, etc., before use in a method of the invention.
In a particular embodiment, the invention thus relates to a method for detecting a HIV gp41 protein in a sample, comprising:
(i) contacting the sample with a monoclonal antibody, variant or fragment of the invention, and
(ii) detecting the presence of an antibody:antigen complex formed in step (i).
The invention is particularly relevant since the antibodies of the invention can detect or quantify the relevant (or reactive) form of gp41. Indeed, by targeting the PEP3 domain, essentially reactive gp41 protein is measured, which thus provides a relevant information about the disease/patient status.
The invention thus relates to a method for monitoring progression of HIV disease in a subject in need thereof, comprising in vitro quantifying gp41 at different time intervals in a plasma sample from the subject using a monoclonal antibody, variant or fragment of the invention.
The method of the invention may be used e.g., for monitoring anti-HIV treatment efficacy.
The method of the invention may also be used for determining if an HIV-infected subject can benefit from anti-PLA2G1B immunotherapy, preferably anti-PLA2G1B antibody therapy or trans CD4 immunotherapy.
The method of the invention can also be used for determining the severity of HIV disease in a subject, wherein an increased level of binding of the monoclonal antibody, variant or fragment of the invention in said sample as compared to a reference value is indicative of severity. For use in the invention, the reference value may be a value determined at an earlier stage in a sample from the same subject, or a mean value.
The invention mays also be used to monitor/follow the amount of gp41 (fragment) in the plasma of HIV-infected patients treated with antiretroviral molecules and correlate the gp41 levels with PLA2GIB activity and outcome of the disease.
In a further aspect, the present invention relates to kits comprising a least one antibody, or a variant or fragment thereof, as herein described, in a container (such as a plate, microplate, tube, bottle, flask, etc. The kit of the invention preferably further comprise one or more reagent(s) to perform, detect or quantify an immune reaction, or an antibody-antigen complex. The one or more reagents may be selected from e.g., diluents, substrates, labels, marker antibodies, etc., adapted to any immune reaction such as ELISA, RIA, etc.
Method of Treating HIV
The antibodies and compositions of the invention may further be used for treating HIV disease in a subject in need thereof.
In a further aspect, the invention relates to methods for treating HIV comprising administering to a subject in need thereof a composition or antibody, fragment or variant thereof as defined above.
In a further aspect, the invention relates to a composition or antibody, fragment or variant thereof as defined above for use for treating HIV disease.
As used herein, “treatment” or “treat” refers to clinical intervention in an attempt to alter the natural course of the individual being treated, and can be performed either for preventive or curative purpose. Desirable effects of treatment include, but are not limited to, preventing occurrence or recurrence of disease, alleviation of symptoms, diminishment of any direct or indirect pathological consequences of the disease, reducing viral load or replication or virulence, decreasing the rate of disease progression, amelioration or palliation of the disease state, and remission or improved prognosis. In some embodiments, compositions and methods of the invention are used to delay development of a disease or disorder or to slow the progression of a disease or disorder.
The duration, dosages and frequency of administering compounds or compositions of the invention may be adapted according to the subject and disease. The treatment may be used alone or in combination with other active ingredients, either simultaneously or separately or sequentially.
Further aspects and advantages of the invention are disclosed in the following experimental section.
Materials and Methods
Recombinant proteins and peptides—Human PLA2-GIB was produced in E. coli (gift Gerard Lambeau, purity>98%) or in CHO-S (purity>98%). HIV-1 MN gp41 (Genbank accession #AAC31817.1) recombinant protein was produced in E. coli and was obtained from Antibodies onlines (MN gp41 (565-771Delta642-725), ABIN2129703, lot 93-482, purity>95%). HXB2 gp41 recombinant protein (GenBank accession #AAB50262.1, a.a. 534-681, purity>95%) was purified from 293 cell culture and purchased from antibodies online (ABIN1605865). HIV-1 MN gp41 (GenBank accession #AAC31817.1, a.a. 542-666), D117 III gp41 (GenBank accession #AAM08364.1, a.a. 532-656) (see alignment of recombinant proteins used, slide Methods), and D117 III gp120 (Genbank accession #AAM08364.1, a.a. 31-482) were produced in S2 cells and purified at DIACCURATE (purity>98%). PEP3 peptide NH2-PWNASWSNKSLDDIW-COOH and control peptide (CTL) NH2-PWNATWTQRTLDDIW-COOH were ordered from Covalab (purity>98%).
Development of anti-gp41 antibodies—Antibodies specific for the PEP3 sequence (PWNASWSNKSLDDIW) in HIV-1 MN strain gp41 were generated at BIOTEM (France) by immunization of OF1 mice with the peptide NH2-C-PWNASWSNKSLDDIW-COOH conjugated to KLH (KLH-PEP3). Mice were immunized 5 times every 3 weeks. First immunization was subcutaneous and intraperitoneal with 50 μg of peptides and complete freund's adjuvant. Then mice were intraperitoneally injected three times with 50 μg of peptides and incomplete freund's adjuvant. The antibody titer in serum was evaluated by ELISA on PEP3 and MN gp41 protein (ABIN2129703). The mouse with the best titer on protein and peptide was selected and injected intravenously with 5 μg of KLH-PEP3 alone. Three days later the spleen was collected and cells were fused with myeloma (Sp2/0-Ag14) cells to generate hybridoma. Among 1093 supernatants from fusion 1072 were positive on BSA-PEP3 peptide. The best 123 were selected and tested another time on BSA-PEP3 peptide and MN gp41. The isotypes of 27 clones were determined and they were frozen including 6 clones that were maintained in cell culture to obtain stable clone (Table 1). These 6 clones, 4G1, 8D5, 3A2, 15B4, 5E12 and 9B12, were seeded in High Yielding Performance Flask (hyperflask) for cell culture to produce 560 ml of supernatant with 10% Low IgG fetal bovine serum (FBS) in DMEM medium. IgG were purified from supernatant by affinity chromatography on protein A in low endotoxin condition (<10 EU/mg, LAL test). Antibodies binding to BSA-PEP3, MN gp41 and HXB2 gp41 was studied as indicated in the patent and the cDNA sequence coding the variable regions of these antibodies was determined (see below).
Anti-HR2 antibodies specific for the sequence 5184-3 (EKSQTQQEKNEQELLELDK, a.a. 648-666, into HR2 region) in HIV-1 MN strain gp41 were generated at BIOTEM (France) by immunization of OF1 mice with the peptide NH2-C-EKSQTQQEKNEQELLELDK-COOH conjugated to KLH (KLH-5184-3). 3 mice were immunized 5 times with 3 weeks between the first 3 immunizations and immunizations #4 and #5 but 4 months between immunizations #3 and #4. First immunization was subcutaneous and intraperitoneal with 20 μg (S11 and S12 mice) or 50 μg (S13 mouse) of peptides and complete freund's adjuvant. The second immunization was intraperitoneal with 20 μg (S11 and S12 mice) or 50 μg (S13 mouse) of peptides and incomplete freund's adjuvant. Third and fourth injection were intraperitoneal with 10 μg of peptides and incomplete freund's adjuvant. The antibody titer in serum was evaluated by ELISA on 5184-3 peptide, MN gp41 and HXB2 gp41. Mice S12 and S13 had the best titers. Thus they were both intravenously injected with 2.5 μg of both MN gp41 and HXB2 gp41. Three days later the spleen was collected and cells were fused with myeloma (Sp2/0-Ag14) cells to generate hybridoma. Among 515 supernatants from fusion of S12 mouse cells, 3 were positive on BSA-5184-3 peptide by ELISA and confirmed by ELISA on BSA-5184-3, MN gp41 (produced in S2 cells) and HXB2 gp41 proteins (63G4, 69D6 and 67D7). Among 301 supernatants from fusion of S13 mouse cells, 1 was positive on BSA-5184-3 peptide by ELISA and confirmed by ELISA on BSA-5184-3, MN gp41 and HXB2 gp41 proteins (72D7). We obtained 4 clones that produced anti-HR2 Ab (anti-5184-3). They were frozen and the isotype was determined.
ELISA—ELISA on peptides or proteins were performed on microtiter plates coated overnight at room temperature (RT) with 50 μl of a solution in PBS (pH7.4) of BSA-PEP3, MN gp41 protein (screening of anti-PEP3 Ab,
ELISA with anti-PEP3 mAb on coated MN gp41 (produced in S2 cells) or HXB2 gp41 (
To further study anti-PEP3 mAbs their pairing with biotinylated 4G1 or biotinylated goat anti-gp41 pAb (PA1-73100, Thermofisher Scientific) were tested by sandwich ELISA (
To further study the pairing of 72D7 with 4G1 or goat anti-g41 pAb, 72D7 was tested as capture Ab and the biotinylated 4G1 or anti-gp41 pAb were tested as detection Ab (
Sequencing and analysis of cDNA coding variable region of the 6 anti-PEP3 mAbs—RNA was extracted from cloned hybridoma and reverse transcribed into cDNA at BIOTEM (France) with high fidelity reverse transcriptase. The cDNA was amplified by PCR with high fidelity Taq polymerase and degenerated primers flanking variable regions of light and heavy chains. Both strands of the bulk of PCR products were directly sequenced. Sequences were aligned to obtain sequences coding the variable domains of light (VL) and heavy (VH) chains with partial sequences of the constant domains. Based on these nucleotide sequences, protein sequences were deduced and isotypes of light and heavy chains were confirmed. Using the IMGT web site, (the international ImMunoGeneTics Information System® http://www.imgt.org) the percentage of identity between anti-PEP3 mAb VL and VH sequences and mouse germinal sequences was determined, the functional structure subdomains FR1-FR4 and CDR1-3 and a model of representation of 3D structures in colliers de Perles (IMGT Colliers de Perles) were predicted.
Characterization of monoclonal 4G1 anti-gp41 specificity on gp41 and gp120 recombinant proteins—Recombinant MN gp41, D117 III gp41 and D117 III gp120 were produced in S2 cells. Microtiter plates were coated in triplicate with 10 μg/well of either recombinant D117 III gp120 or recombinant D117 III gp41 in carbonate buffer pH 9.6. After overnight incubation at 4° C., nonspecific binding sites were blocked with Pierce blocking buffer (37572, Pierce). Anti-PEP3 mAb 4G1 was added to a final dilution of 1 μg/well in blocking buffer. Bound antibody was detected by interaction with a goat-anti mouse HRP-conjugated antibody, followed by the addition of 100 μl/well TMB substrate (UP664781, Interchim). The reaction was stopped by adding 50 μl 0.1 M H2SO4 and the O.D.450nm was measured using a Tecan Infinite M1000 Pro.
For western blot analysis, 500 ng or 1 μg of recombinant MN gp41 or D117 III gp120 proteins were run on 4%-20% Tris-Bis SDS-PAGE (BIO-RAD) gels under reducing conditions. Antigens were transferred to PVDF membranes (BIO-RAD) using a Trans-Blot Turbo (BIO-RAD). After blocking nonspecific binding sites with 5% skimmed milk/0.05% tween 20 in PBS, antibody binding was tested at 1 μg/ml for 4G1 and 5 μg/ml for the polyclonal anti-gp41 (PA1-7219, Thermofisher). Goat anti-mouse (31430, Pierce) and donkey anti-goat (705-035-003, Jackson Immunoresearch) HRP-conjugated antibodies were used at a 1:10,000 dilution. Detection occurred directly on the membrane using SuperSignal West Pico Plus Substrate (34580, ThermoScientific).
Purification of Human CD4 T-lymphocytes—Venous blood was obtained from healthy volunteers through the EFS (Etablissement Français du Sang, Centre Necker-Cabanel, Paris). CD4 T-cells were purified from whole blood using RosetteSep Human CD4+ T cell Enrichment Cocktail (Stem Cell, 15062). This cocktail contains mouse and rat monoclonal antibodies purified from mouse ascites fluid or hybridoma culture supernatant, by affinity chromatography using protein A or Protein G sepharose.
These antibodies are bound in bispecific tetrameric antibody complexes which are directed against cell surface antigens on human hematopoietic cells (CD8, CD16, CD19, CD36, CD56 CD66b, TCRγ/δ) and glycophorin A on red blood cells. The rosetteSep antibody cocktail crosslinks unwanted cells in human whole blood to multiple red blood cells, forming immunorosettes. This increases the density of unwanted cells, such that they pellet along with the free red blood cells when centrifuged over a buoyant density medium such as lymphocytes separation medium (Eurobio, CMSMSL01-01).
Whole blood was incubated with RosetteSep Human CD4+ T cell Enrichment Cocktail at 50 μl/ml for 20 minutes at room temperature under gentle shaking (100 rpm), diluted with an equal volume of PBS/2% FBS and mixed gently. The diluted samples were centrifuged 20 minutes at 1200× g on top of lymphocytes separation medium. The enriched cells were then collected from the density medium at plasma interface and washed twice with PBS/2% FBS. Cells were subsequently resuspended in RPMI 1640 medium (Lonza) supplemented with 5% FBS, 50 mM HEPES pH 7.4, glutamine, penicillin, streptomycin and fungizone (complete medium), counted with a Moxi Z mini automated cell counter (ORFLO, MXZ000). Cells suspension was adjusted at 7×106 cells/ml and equilibrated at least 2 h at 37° C. in a 5% CO2 humidified atmosphere.
The enriched CD4-T cell population was controlled by flow cytometry on a cytoflex (Beckman coulter). The quiescence of recovered CD4 T-cells was controlled by the low level of IL-2Rα (CD25). CD4 T cells were labeled with anti-Human CD3 eFluor780 (eBioscience, clone UCHT1, 47-0038-42), anti-Human CD25-PE (Biolegend, clone BC96, 302605) and anti-human CD4-PerCP (BD, clone SK3, 345770). The enriched CD4-T cell population contains >95% CD3+CD4+ and less than 8% of CD25+.
PLA2-GIB bioassay on CD4 T cells and labelling of specific proteins for optical microscopy—Equilibrated purified CD4 T-cells were loaded (3.5×105 cells/50 μl in complete medium) on poly-L-Lysine-coated (Sigma, P8920) round coverslips (14 mm-diameter, Marienfeld) in 24-well polystyrene plates at 37° C. in a thermo-regulated water and mixed with 50 μl of a suspension in PBS/1% BSA containing peptides, recombinant proteins together with recombinant PLA2-GIB or not or containing viremic patient plasma (1 or 3%) or healthy donor plasma. The cells suspension was either pretreated with 40 μl of peptides, recombinant protein or HIV-1 NDK particles or mock dilutions in PBS/1% BSA for 15 minutes with subsequent addition of 10 μl PLA2-GIB (5 nM at the end) for 30 minutes or directly treated with 50 μl of dilution in PBS BSA 1% with peptides or recombinant protein together with PLA2-GIB (5 nM at the end) for 45 minutes. Cells were activated for 15 minutes with 2 nM recombinant glycosylated human IL-7 (Accrobio System). Cells supernatant was removed and cells were fixed by addition of 500 μl of a 4% paraformaldehyde solution in PBS (Fisher, PFA 32% Electron Microscopy Science, 15714) for 15 minutes at 37° C. and then permeabilized overnight in 500 μl of ice-cold 90% methanol/water solution.
Cells were then rehydrated for 15 min in PBS plus 5% FBS and then labeled. Thus, slides were washed twice after methanol treatment in PBS and rehydrated for 15 min in PBS supplemented with 5% FBS at room temperature. Slides were labelled with primary antibodies (1/120) in 60 μl of PBS 5% FBS for 1 h, washed in PBS buffer 15 times, 5 times in PBS/FBS buffer and then stained with secondary antibodies (1/300) for 1 h. Slides were washed 5 times in PBS 5% FBS buffer, rinsed 15 times in PBS and then mounted in fresh Prolong Gold Antifade (ThermoFisher Scientific, P36930) mounting medium for confocal microscopy. The primary antibodies used consisted of rabbit anti-pSTAT5 (pY694, 9359, Cell Signalling), mouse anti-CD4 (BD Pharmingen, 555344) and secondary antibodies were Donkey anti-mouse IgG-AF488 (Invitrogen, A21202) and Donkey anti-rabbit IgG-AF555 (Invitrogen, A31572).
Confocal Microscopy—Images were acquired above the diffraction limit on an inverted laser scanning confocal microscope (LSM700, Zeiss), with an oil-immersion plan-apochromatic 63x/1.4 NA objective lens (Zeiss) for PFA-fixed cells. Images were acquired and analyzed with the ZEN software (Zeiss).
Determination of gp41 and PEP3 plasma cofactor peptide activity on healthy donor CD4 T cells—The role of plasma gp41 as a regulator of PLA2-GIB activity was evaluated by immunodepleting endogenous gp41 with specific antibodies. Briefly, 1 ml VP or HD plasma was incubated with 100 μg goat anti-gp41 polyclonal antibody (PA1-7219, Thermofisher) or the control goat polyclonal antibody (preimmune, AB108-C, R&D Systems), to immunodeplete gp41, in 1.5-ml Eppendorf tubes overnight (Test tube-rotor, 34528, Snijders, Netherland) at 4° C. As the goat anti-gp41 pAb initially contained 0.1% sodium azide, it was washed five times with PBS on 10 kDa Amicon (051828, Millipore) spin filters by centrifugation at 16,100×g for 2 min at 4° C. to remove the sodium azide before proceeding to immunodepletion. The normal goat IgG control was treated similarly as the anti-gp41 pAb. Then, 200 μl Protein G Sepharose 4 Fast Flow beads (17-0618-01, GE healthcare), that had been washed three times in PBS/1% BSA, was added to each sample and the samples incubated for 3h at 4° C. Beads were removed by centrifugation of the samples at 400× g for 2 min at 4° C., collection of the supernatant then centrifugation at 16,100×g for 15 min at 4° C. The goat anti-gp41 pAb bind specifically to recombinant gp41 but not gp120 (
VP or HD plasma (500 μl) from three VPs and three HDs were fractionated on Amicon spin filters with a 30 kDa cut-off (051850, Millipore) and then a 10 k Da cut-off (051828, Millipore). The 10-30 kDa fraction was collected and treated with control isotype (Mouse IgG2b/k, 16-4732-85, Thermofisher) or gp41 was immunodepleted with 100 μg of 4G1 mAb as described above. The 4G1 mAb bind specifically to recombinant gp41 but not gp120 (
The effect of gp41 on PLA2-GIB activity on CD4 T cells was assessed by incubating purified CD4 T cells in PBS/1% BSA containing peptides, recombinant proteins, together or not with recombinant PLA2-GIB, VP or HD plasma, or the 10-30 kDa fraction previously depleted, or not, of gp41.
The effect of the recombinant gp41 and PEP3 gp41 peptide on PLA2-GIB activity was tested by pretreating the cell suspension for 15 min with 40 μl of the recombinant gp41 protein or peptides with subsequent addition of 10 μl PLA2G1B for 30 min (
Results and Discussion
1. HIV-1 gp41 Increases PLA2-GIB Inhibitory Activity on pSTAT5 NT in CD4 T Cells Stimulated with IL-7
We analyzed pSTAT5 NT response to IL-7 in cells pretreated with a dose of PLA2-GIB that cannot inhibit pSTAT5 NT in absence of cofactor (5 nM), together or not with a recombinant gp41 protein or with gp41 protein alone, without PLA2-GIB (w/o GIB). As shown on
2. The PEP3 Motif in gp41 Inhibits pSTAT5 NT in CD4 T Cells Stimulated with IL-7
CD4 T cells were exposed to a 15 amino acids peptide domain of gp41 containing a gC1qR binding element and a highly conserved SWSNKS motif. The cells were also exposed to a control (CTL) peptide (
3. HIV-1 gp41 Protein Plays a Critical Role in the Inhibitory Activity of Viremic Patient Plasma on pSTAT5 NT in CD4 T Cells Stimulated with IL-7
We first identified polyclonal antibodies that are specific of gp41 relatively to gp120, another HIV envelope subunit, in immunoblot (
4. Development of Anti-PEP3 Monoclonal Antibodies
The above demonstration that PEP3 peptide alone is able to increase the inhibitory activity of PLA2-GIB (
5. The 4G1 Anti-PEP3 mAb Almost Abrogates the Inhibitory Activity of Viremic Patient Plasma on pSTAT5 NT in CD4 T Cells Stimulated with IL-7
We depleted viremic patient (VP) plasma with the 4G1 anti-PEP3 mAb (anti-PEP3 mAb) or control isotype (mAb ctrl). The plasma of healthy donor (HD) was similarly treated as negative control. The inhibition of pSTAT5 NT was 47% with 75 nM and 67% with 250 nM of PLA2-GIB and 49% with 1% and 58% with 3% of VP plasma without antibody (
6. Detection of gp41 in HIV Viremic Plasma: Development of Anti-gp41 Ab and ELISA
Another challenge is to quantify gp41 products in the plasma of HIV viremic patient. The presence of anti-gp41 antibodies in the plasma of HIV viremic patients has been well described (Boyd and James, 1992; Butler et al., 2019; Mikell et al., 2011; Trama et al., 2014; Vaidya et al., 2018; Williams et al., 2015). The first anti-HIV protein monoclonal antibodies observed from blood plasma cells of acute HIV-1-infected individuals are predominantly targeted to gp41 (Butler et al., 2019; Trama et al., 2014). However to our knowledge the gp41 protein has never been detected in the plasma of HIV infected patients which suggests that the concentration of gp41 is very low and/or the anti-gp41 antibodies that have been developed have too low affinity to allow the detection of gp41 in plasma.
Among the 6 anti-PEP3 mAbs we developed, the 4 mAbs that bind with the highest affinity to gp41 proteins are 4G1, 8D5, 3A2 and 15B4 (
In order to further increase the efficiency of the antibodies to detect gp41 in ELISA, we generated additional antibodies against gp41. Our experiments have shown that the gp41 fragment in VP plasma contains the PEP3 sequence and is into the 10-30 kDa fraction of VP plasma. So, we hypothesized that it could be a part of/or the ectodomain of the gp41 protein. We thus decided to immunize OF1 mice against the peptide that we named 5184-3 present at the C-terminal part of the second heptad repeat region (HR2) of gp41 (
We selected two mice (S12 and S13) based on the titer of their serum on 5184-3 peptide and HXB2 gp41 protein. Among 816 supernatants 4 clones that produced anti-HR2 Ab (anti-5184-3) were positive on BSA-5184-3 peptide by ELISA and confirmed by ELISA on BSA-5184-3, MN gp41 (produced in S2 cells) and HXB2 gp41 protein (63G4, 69D6 and 67D7 from mouse S12 and 72D7 from mouse S13,
Then we tested the 4 anti-HR2 Ab capacity to be used in sandwich ELISA with 4G1 mAb. A mini production of these anti-HR2 antibodies was performed in vivo after injection of hybridoma in nude mice. Purity and quantity obtained were high for 67D7 and 72D7 but low for 63G4 and 69D6 (
Then the pairing of 4G1, 63G4, 69D6, 67D7 and 72D7 as capture Ab and 4G1-biot, 72D7-biot and 67D7-biot as detection Ab were tested using HXB2-gp41 antigen (
The pairing of 72D7 with 4G1-biot was confirmed on various dilutions of HXB2 gp41 protein and compared with goat anti-gp41 pAb (
7. Test of Detection and Quantification of gp41 Fragment in Plasma of HIV Viremic Plasma Using the Single Molecule Array (SIMOA) Technology.
The concentration of gp41 in the plasma of HIV viremic plasma is probably very low, that would explain that even if anti-gp41 antibodies have been well described in the plasma of viremic patient plasma, the gp41 protein itself has not been detected by classical ELISA or immunoblot assays. The anti-PEP3 and 72D7 mAb can be used to detect gp41 in VP plasma using the ultrasensitive technique SIMOA that in general increases the 1000-fold the sensitivity in comparison to ELISA.
| Number | Date | Country | Kind |
|---|---|---|---|
| 19306033.2 | Aug 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/073805 | 8/26/2020 | WO |
