Monoclonal immunoglobulin G1 directed against Aspergillus fumigatus cell wall glycoprotein protects against experimental murine aspergillosis

Most of the biological functions related to pathogenicity and virulence reside in the fungal cell wall, which, being the outermost part of the cell, mediates the host-fungus interplay. For these reasons much effort has focused on the discovery of useful inhibitors of cell wall glucan, chitin, and mannoprotein biosynthesis. In the absence of a wide-spectrum, safe, and potent antifungal agent, a new strategy for antifungal therapy is directed towards the development of monoclonal antibodies (MAbs). In the present study the MAb A9 (immunoglobulin G1 [IgG1]) was identified from hybridomas raised in BALB/c mice immunized with cell wall antigen of Aspergillus fumigatus. The immunoreactive epitopes for this IgG1 MAb appeared to be associated with a peptide moiety, and indirect immunofluorescence microscopy revealed its binding to the cell wall surface of hyphae as well as with swollen conidia. MAb A9 inhibited hyphal development as observed by MTT [3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (25.76%), reduced the duration of spore germination, and exerted an in vitro cidal effect against Aspergillus fumigatus. The in vivo protective efficacy of MAb A9 was also evaluated in a murine model of invasive aspergillosis, where a reduction in CFU (>4 log(10) units) was observed in kidney tissue of BALB/c mice challenged with A. fumigatus (2 x 10(5) CFU/ml) and where enhanced mean survival times (19.5 days) compared to the control (7.1 days) and an irrelevant MAb (6.1 days) were also observed.     

Monoclonal antibodies against Neisseria gonorrhoeae: production of antibodies directed against a strain-specific cell surface antigen.

Hybridomas secreting monoclonal antibodies against an apparent strain-specific cell surface antigen of Neisseria gonorrhoeae were produced. Spleen cells from BALB/c mice immunized with whole gonococci were fused with mouse myeloma cell line Sp2/0, and hybrid cells were selected in culture. One hybridoma that secreted antibodies reactive with the immunizing strain was cloned by limiting dilution to obtain cell lines secreting monoclonal antibodies. These antibodies reacted with purified outer membranes from the immunizing strain as well as with whole gonococci. Binding of antibodies to whole gonococci was highly strain specific, with most gonococcal strains showing less than 1% of the binding with the immunizing strain. Antibodies did not bind to the other Neisseria species tested. Binding of monoclonal antibodies to whole gonococci of the immunizing strain was not dependent on state of piliation. The extent of antibody binding did vary in different colonial variants of the immunizing strain. Antibody bound to cells from colonies that were transparent or of intermediate opacity, but did not bind to cells from deeply opaque colony variants.     

Monoclonal antibody to neural cell surface protein: identification of a glycoprotein family of restricted cellular localization

A monoclonal antibody, designated anti-NSP-4 (anti-Neural cell Surface Protein-4), was obtained from a hybridoma generated by fusing rat myeloma cells with splenocytes of a rat immunized with membranes from the cerebella of weaver mutant mice. This antibody reacted with several high-molecular weight polypeptides in extracts prepared from the newborn and adult CNS of wild-type mice. The main NSP-4-reactive bands from neonatal cerebellum and spinal cord migrated with apparent molecular weights of 220,000 and 140,000. Major bands of 160,000 and of 175,000, 160,000 and 140,000 molecular weight were revealed in the adult cerebellum and spinal cord, respectively. Reaction of the antibodies with concanavalin A-binding proteins demonstrated the glycoprotein nature of the antigen. Cell types expressing NSP-4 antigen were determined using indirect immunofluorescence on monolayer cultures of early postnatal mouse cerebellar and dorsal root ganglion cells and on sections of developing and adult mouse cerebellum. In cerebellar cultures, the antibody reacted with the surface membrane of a subpopulation of astrocytes and of a small subset of neurones. In dorsal root ganglion cultures, anti-NSP-4 antibodies were highly specific for a subclass of small neurones. Staining for NSP-4 in sections of adult cerebellum was confined to the granular layer where the antibody seemed to label astroglia. In the developing cerebellum, NSP-4 staining outlined cell bodies of neuroblasts and migrating granule cells in the external granular layer. Post-migratory granule cells and Purkinje cells were negative. As in the adult, the labeled structures in the internal granular layer were probably astrocytes. Our results on the in vivo and in vitro localization of NSP-4 show its expression by subclasses of neurones and astrocytes in the cerebellum and by a subclass of neurones in cultures from the peripheral nervous system. The developmentally-regulated changes in the molecular weight forms of the NSP-4 antigen together with the shift in its cellular localization during cerebellar ontogeny suggest a functional significance for this antigen in developmental processes.     

抗血小板糖蛋白Ⅵ单克隆抗体的制备及其功能研究

目的：制备抗血小板糖蛋白Ⅵ（GPⅥ）单克隆抗体，观察其在体外抗血小板黏附和聚集功能。方法：采用基因重组技术体外表达血小板糖蛋白Ⅵ胞外区重组蛋白（rGPⅥ）。以rGPⅥ免疫小鼠，经细胞融合及筛选后制备抗GPⅥ单克隆抗体。采用血小板聚集实验观察该单抗对胶原、Convulxin及ADP诱导的血小板聚集的影响；利用平行板流动小室技术研究在高剪切力条件下该单抗对血小板在胶原表面黏附的抑制效果。结果：正确构建了rGPⅥ表达载体pET-20b（＋）-GPⅥ，rGPⅥ在原核细胞中有效表达。rGPⅥ能够被抗Penta-His单抗和抗GPⅥ多抗识别。制备的抗GPⅥ单克隆抗体SZ118能够识别rGPⅥ，并与血小板有特异的结合能力。SZ118能明显抑制纤维状胶原和Convulxin诱导的血小板聚集，呈抗体剂量依赖性；对ADP诱导的血小板聚集无明显影响。血小板黏附实验表明，SZ118能够明显阻断在高剪切力条件下血小板与纤维状胶原表面的黏附。结论：成功制备抗GPⅥ单克隆抗体SZ118，该抗体与血小板有良好的结合能力，显著抑制胶原诱导的血小板聚集并明显降低血小板与胶原的黏附反应。     

抗血小板糖蛋白VI单克隆抗体的制备及其功能研究

目的:制备抗血小板糖蛋白VI(GPVI)单克隆抗体,观察其在体外抗血小板黏附和聚集功能。方法:采用基因重组技术体外表达血小板糖蛋白VI胞外区重组蛋白(rGPVI)。以rGPVI免疫小鼠,经细胞融合及筛选后制备抗GPVI单克隆抗体。采用血小板聚集实验观察该单抗对胶原、Convu lxin及ADP诱导的血小板聚集的影响;利用平行板流动小室技术研究在高剪切力条件下该单抗对血小板在胶原表面黏附的抑制效果。结果:正确构建了rGPVI表达载体pET-20b(+)-GPVI,rGPVI在原核细胞中有效表达。rGPVI能够被抗Penta-H is单抗和抗GPVI多抗识别。制备的抗GPVI单克隆抗体SZ118能够识别rGPVI,并与血小板有特异的结合能力。SZ118能明显抑制纤维状胶原和Convu lxin诱导的血小板聚集,呈抗体剂量依赖性;对ADP诱导的血小板聚集无明显影响。血小板黏附实验表明,SZ118能够明显阻断在高剪切力条件下血小板与纤维状胶原表面的黏附。结论:成功制备抗GPVI单克隆抗体SZ118,该抗体与血小板有良好的结合能力,显著抑制胶原诱导的血小板聚集并明显降低血小板与胶原的黏附反应。     

Inhibition of T cell responses in vitro by an antibody against a novel lymphocyte surface molecule (QCA-1)

We have identified an antigen present on the surface of lymphocytes in the rat which appears to play an important role in the preliminary stages of the immune response. This antigen, which we have called quiescent cell antigen 1 because of its apparent expression only on quiescent cells, is present on the majority of peripheral T and B cells and a small percentage of thymocytes which are located mainly in the medullary region. SDS-PAGE analysis of membrane molecules shows two bands on unreduced gels at approximately 43 and 47 kd. On reduction the bands ran at approximately 46 and 60 kd. When a monoclonal antibody against this antigen (HIS45) is present in an allogeneic mixed leukocyte reaction, it inhibits the proliferation of responding cells completely. When the antibody HIS45 is added to cytotoxic T lymphocyte mediated lysis assays it does not inhibit lysis nor does it affect the specificity of this lysis. Comparison with other antibodies which have been reported to affect lymphocyte function in rats and in other species fail to reveal any which have similar properties.     

Monoclonal antibodies selectively directed against the cell wall surface of Mycobacterium tuberculosis.

In the last few years several monoclonal antibodies against Mycobacterium tuberculosis have been described, but their use as diagnostic tools has been limited. In this study we describe eight monoclonal antibodies against M. tuberculosis for diagnostic purposes. The monoclonal antibodies were selected after enzyme-linked immunosorbent assay screening with whole bacterial suspensions of mycobacteria and other bacterial species. Four monoclonal antibodies (BS100, BS101, BS102, and BS104) reacted with a whole bacterial suspension of M. tuberculosis but not with the other mycobacteria. When tested with a cytoplasmic fraction of mycobacteria the same monoclonal antibodies showed a broad cross-reactivity. Therefore the monoclonal antibodies showed not specific but selective binding to M. tuberculosis. The molecular size of the recognized antigens ranged from 12 to 71 kilodaltons as determined by the immunoblotting technique. The ability to differentiate M. tuberculosis from mycobacteria other than tuberculosis was investigated by enzyme-linked immunosorbent assay with 131 freshly cultured strains of M. tuberculosis from patients and 36 strains of mycobacteria other than tuberculosis. The monoclonal antibody BS104 could clearly distinguish between M. tuberculosis and other mycobacterial species.     

Monoclonal antibody directed against neuroendocrine properties of both normal and malignant cells

A monoclonal antibody, 6H7, was produced by the immunization of small cell carcinoma of the lung (SCCL). Immunohistochemical examination indicated that 6H7 reacted not only with SCCL but also various neuronal and/or endocrine tumors such as neuroblastoma, pheochromocytoma, carcinoid and adrenal cortical tumors. 6H7 was also reactive with normal neuroendocrine tissues including brain, spinal cord, thyroid follicular cells, pancreatic islet cells and adrenal cells. 6H7 did not react with squamous cell carcinomas, one large cell carcinoma or most adenocarcinomas of the lung, or carcinomas of the stomach, colon, pancreas, breast and esophagus. The antigen recognized by 6H7 was analyzed on gel filtration after purification of the antigen by liquid chromatography which indicated the molecular weight of the antigen to be 270,000-300,000. From SDS-PAGE analysis the antigen reactive with 6H7 appeared to consist of polypeptide dimers of 128,000.     

Monoclonal antibody against a serotype antigen of Porphyromonas (Bacteroides) endodontalis and characteristics of the antigen.

Recent studies have demonstrated the presence of three serotypes (O1K1, O1K2, and O1K-) of Porphyromonas (Bacteroides) endodontalis. In the present study, a hybridoma cell line producing monoclonal antibody (BEE11) specific for serotype O1K1 of P. endodontalis was established. The specificity of the antibody was evaluated by enzyme-linked immunosorbent assay and immunoslot blot analysis. BEE11 antibody reacted with strains ATCC 35406, HG 400, and HG 421 of the bacterium. However, it did not react with HG 422 or HG 948. Also, the antibody did not react with any of the black-pigmented Bacteroides strains tested. Although the antibody reacted with total cell envelope and capsule materials, it did not do so with lipopolysaccharide. The antibody reacted with antigen material having a molecular mass of 110 kilodaltons (kDa), as judged from fractionation by Superose 12 prep gel chromatography. When the peak fraction from the Superose 12 column was subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot (immunoblot) analysis, the reactivity was detected as a single band at an apparent molecular mass of about 52 kDa. The antigen material purified partially by high-performance liquid chromatography was sensitive to trypsin, V8 protease, and heating to 80 degrees C but not to neuraminidase. Therefore, the present study shows that BEE11 antibody recognizes a serotype antigen of P. endodontalis which may be a dimer consisting of monomers having molecular masses of approximately 52 kDa and sensitivity to proteases and heat.     

Monoclonal antibodies directed against a 130K glycoprotein of bovine herpesvirus 2 cross-react with glycoprotein B of herpes simplex virus

Envelope proteins of bovine herpesvirus type 2 (BHV-2) and herpes simplex virus types 1 and 2 (HSV-1, -2) share cross-reacting determinants. Monoclonal antibodies directed against epitopes of a 130K glycoprotein of BHV-2 detect determinants on the surface of infected cells and react either with cytoplasmic or nuclear antigens. Biological and biochemical characterization of the proteins recognized by these antibodies revealed that the BHV-2 specific 130K glycoprotein and the gB of HSV share common epitopes. Some of them are involved in the neutralization of HSV and BHV-2.     

Activation of resting T lymphocytes by a monoclonal antibody directed against an allotypic determinant on the T cell receptor

The murine monoclonal antibody F23.1 reacts with an allotypic determinant on the beta chain of the T cell receptor expressed by approximately 20% of T helper and cytotoxic T lymphocytes of most common mouse strains. This IgG2a antibody, either in soluble form or covalently coupled to Sepharose beads, can activate resting T cells from naive animals to proliferate. Interestingly, under all conditions of activation, the antibody can only induce proliferation if exogenous lymphokines in the form of Con A supernatant are provided. Thus, it is unlike most lectins and anti-T3 antibodies in this regard. Furthermore, under all conditions of culture, F23.1 activates preferentially the Lyt-2+ subset of T cells. This is the case even in the presence of accessory cells. Further evidence is provided that two soluble lymphokines, different from IL2, are required to initiate IL2-dependent growth and to allow the expression of lytic activity.     

A monoclonal antibody directed against a synthetic peptide reacts with a cell surface rabbit class I MHC molecule

Monoclonal antibodies were prepared against synthetic peptides synthetized on the basis of nucleotide sequence from cDNA and genomic clones encoding a class I antigen expressed by the rabbit RL-5 cell line. Using a peptide corresponding to positions 61-73 of the N domain, we were able to obtain an hybridoma producing monoclonal antibody which recognized the peptide as well as the native class I antigen. This hybridoma, designated anti-61, reacted with cell surface molecules on RL-5 cells and on human HeLa cells transfected with the 19-1 gene encoding RL-5 class I antigen. No reactivity with HeLa cells prior to transfection could be detected by radioimmunoassay or by fluorescent activated cell sorter analyses, although these cells were strongly positive in both assays with anti-human class I reagents. Antibody reaction to positive cells could be inhibited by the homologous peptide but not by unrelated peptides. Anti-61 antibody precipitated a 41,000 mol. wt molecule from RL-5 cells with an N-terminal amino acid sequence corresponding to the RL-5 class I antigen.     

Monoclonal antibody to a major surface glycoprotein immunogen differentiates isolates and subpopulations of Trichomonas vaginalis.

To produce monoclonal antibodies (MAbs) to highly immunogenic membrane proteins of Trichomonas vaginalis NYH286, the sera of subcutaneously infected BALB/c mice were first monitored for antibody to trichomonad surface proteins. The sera possessed antibody to one major surface protein by 7 days and antibody to numerous other trichomonad membrane proteins by 4 weeks postinfection. A hybridoma was then generated that synthesized an MAb, designated C20A3, which reacted to a parasite-derived glycoprotein possessing a molecular weight of 267,000 (267K glycoprotein). The immunogen corresponded to the single high-molecular-weight immunogenic surface protein recognized by 7-day mouse antisera. The MAb differentiated T. vaginalis isolates by a whole-cell enzyme-linked immunosorbent assay and by indirect immunofluorescence, using either fixed or live organisms. All isolates, however, possessed C20A3-reactive material when tested by enzyme-linked immunosorbent assay, using detergent extracts of the isolates incubated with MAb-coated microtiter well plates. The epitope was accessible to antibody binding on live T. vaginalis organisms expressing the major immunogen, and the 267K glycoprotein was readily removed from the parasite membranes by trypsinizing the intact trichomonads. The antigen incorporated radiolabeled glucose, mannose, and acetate. Also, an unlabeled 267K glycoprotein on nitrocellulose blots was detected by 125I-concanavalin A and 125I-wheat germ agglutinin, confirming the glycoprotein nature of the immunogen. Finally, of seven isolates used in this study, one possessed a cross-reactive 170K, rather than 267K, antigen. The data reinforce the idea that antigenic heterogeneity among T. vaginalis isolates may be a function of the presence or absence of high-molecular-weight glycoprotein immunogens from trichomonal membranes.     

RASA, a recombinant single-chain variable fragment (scFv) antibody directed against the human sperm surface: implications for novel contraceptives

BACKGROUND: A recombinant single-chain variable fragment (scFv) antibody was engineered to a tissue-specific carbohydrate epitope located on human sperm agglutination antigen-1 (SAGA-1), a sperm glycoform of CD52. METHODS AND RESULTS: cDNAs encoding the variable regions of the S19 [IgG(1)kappa] monoclonal antibody (mAb) were identified, linked, and cloned into the pCANTAB 5E vector. The recombinant anti-sperm antibody (RASA) was expressed in E. coli HB2151 cells as a 29 kDa monomer and, remarkably, also formed multimers of approximately 60 and 90 kDa. RASA reacted with the endogenous SAGA-1 antigen by Western blot analysis, labelled the entire human sperm surface by indirect immunofluorescence, and aggregated human spermatozoa in a tangled (head-to-head, head-to-tail, tail-to-tail) pattern of agglutination, as was also observed with the native S19 mAb. CONCLUSIONS: These results demonstrate that active recombinant antibodies can be produced to a tissue-specific carbohydrate epitope on the human sperm surface, thereby opening opportunities for novel contraceptive agents.     

Lymphocytotoxic antibody in multiple sclerosis: activity against T cell subsets and correlation with disease activity.

Lymphocytotoxic activity has been found by previous investigators in multiple sclerosis (MS) sera. We confirmed the presence of this activity in MS sera using techniques designed to eliminate possible sources of erroneous conclusion not considered in previous studies. We further characterized this activity and found it to be non-dialysable and complement dependent, and, therefore, presumably to be an antibody. This lymphocytotoxic antibody (LCA) is found in those patients with active or progressive disease, and appears to be preferentially directed against the suppressor subset of T cells, as defined by monoclonal antibodies. The LCA may play a role in the pathogenesis of acute exacerbation of MS.     

Development and characterization of a bispecific single-chain antibody directed against T cells and ovarian carcinoma

Bispecific antibodies with specificity for tumor antigen and CD3 have been shown to redirect the cytotoxicity of T cells against relevant tumor. Our objective was to generate single-chain bispecific antibodies (bsSCA) that could retarget mouse cytotoxic T lymphocytes (CTL) to destroy human ovarian carcinoma in a xenogeneic setting. A bsSCA, 2C11 x B43.13, was constructed by genetic engineering and expressed in mammalian cells. Molecular characteristics, binding properties, and ability to retarget CTL were studied. Western blot analysis showed that the product is a 65-kDa protein. Purification of antibodies could be done by single-step affinity chromatography using protein L-agarose with an unoptimized yield of 200 microg/L. BsSCA 2C11 x B43.13 was capable of binding to mouse CD3 and human CA125 as detected by FACS analysis of EL4 and OVCAR Nu3H2 cells, respectively. It could also bridge activated splenic T cells and human ovarian carcinoma as demonstrated by a bridge FACS assay. Redirected mouse CTL could mediate human target cell lysis in a 20-h 51Cr release assay despite that they are xenogeneic. Prolonged incubation of redirected CTL and tumor targets resulted in a dramatic reduction in tumor cell number. CD28 co-stimulation enhanced redirected CTL function in both types of assays. BsSCA 2C11 x B43.13 thus can be used as a preclinical immunotherapeutic model for human ovarian cancer in a xenogeneic setting.     

Monoclonal antibody BM89 recognizes a novel cell surface glycoprotein of the L2/HNK-1 family in the developing mammalian nervous system.

A monoclonal antibody, BM89, obtained with Triton X-114-treated pig synaptic membranes as an immunogen, recognizes a neuronal antigen in the newborn porcine nervous system. By immunohistochemistry, BM89 staining was observed within the neuropil of all areas of the forebrain and spinal cord tested. In addition, BM89 labeled the cell bodies and proximal dendrites of spinal cord neurons. In the peripheral nervous system, BM89 immunoreactivity was present in a subpopulation of dorsal root ganglion neurons and was predominantly associated with non-myelinated axons in peripheral nerves. Initial biochemical characterization of the antigen in pig brain showed that it is an integral membrane glycoprotein with a molecular weight of 41,000. Moreover, it cross-reacts with the L2/HNK-1 carbohydrate epitope expressed by members of a large family of glycoproteins. Homologous antigens with molecular weights of 41,000-43,000 were identified in the rat, rabbit and fetal human brain. Immunoblotting and immunohistochemistry revealed that the epitope recognized by BM89 is developmentally regulated in the rat nervous system. In cryostat sections from rat cerebellum, spinal cord and dorsal root ganglia, an age-dependent decline of BM89 immunoreactivity was observed during postnatal development. In the cerebellum, the BM89 epitope was very abundant in cells of the external and the internal granular layers between postnatal days 5 and 15. During this period some staining was also identified in the developing molecular layer and the prospective white matter. Subsequently, and in the adult, overall staining was greatly reduced and remaining immunoreactivity was associated only with the internal granular layer. In the spinal cord and dorsal root ganglia, staining was very prominent at postnatal day 5; it decreased considerably thereafter and was barely detectable in the adult. Immunostaining of rat brain and dorsal root ganglion cultures revealed that the BM89 antigen is a cell surface molecule expressed by a subpopulation of central and peripheral nervous system neurons. The biochemical properties in conjunction with the topographical location and the developmental profile of the antigen recognized by BM89 suggest that it may represent a developmentally important recognition molecule.     

Monoclonal anti-IL 1 is directed against a common site of human IL 1 alpha and IL 1 beta

Cytokines exhibiting interleukin 1 (IL 1) activity are known as important mediators of immunity and inflammation. Therefore, the ability of a monoclonal anti-IL 1 antibody to neutralize and bind IL 1 was investigated. Anti-IL 1 IgG blocked the IL 1-mediated thymocyte and fibroblast proliferation and also inhibited the biological activity of epidermal cell-derived thymocyte activating factor (ETAF), but did not affect interleukin 2 (IL 2) and interleukin 3 (IL 3) activity. Monoclonal anti-IL 1 blocked the activity and bound to both human IL 1 alpha and IL 1 beta. Additionally using anti-IL 1, it was possible to immunoprecipitate 31 kD, 17 kD and 4 kD biosynthetically radiolabeled biologically active species of IL 1. These data indicate that IL 1 alpha and IL 1 beta share a common site which is responsible for the biological activity. Moreover, this part of the IL 1 molecule also appears to be located within the low mw 4 kD break-down product. Since anti-IL 1 also was capable to detect surface bound IL 1 on LPS-stimulated mononuclear adherent cells, the antibody may help to elucidate the role of surface IL 1 during an immune response. In addition, anti-IL 1 IgG may be very helpful to investigate the in vivo role of IL 1 during the pathogenesis of inflammatory diseases.     

Mapping the conformational epitope of a neutralizing antibody (AcV1) directed against the AcMNPV GP64 protein

The envelope glycoprotein GP64 of Autographa californica nucleopolyhedrovirus (AcMNPV) is necessary and sufficient for the acid-induced membrane fusion activity that is required for fusion of the budded virus (BV) envelope and the endosome membrane during virus entry. Infectivity of the budded virus (BV) is neutralized by AcV1, a monoclonal antibody (MAb) directed against GP64. Prior studies indicated that AcV1 recognizes a conformational epitope and does not inhibit virus attachment to the cell, but instead inhibits entry at a step following virus attachment. We found that AcV1 recognition of GP64 was lost upon exposure of GP64 to low pH (pH 4.5) and restored by returning GP64 to pH 6.2. In addition, the AcV1 epitope was lost upon denaturation of GP64 in SDS, but the AcV1 epitope was restored by refolding the protein in the absence of SDS. Using truncated GP64 proteins expressed in insect cells, we mapped the AcV1 epitope to a 24 amino acid region in the central variable domain of GP64. When sequences within the mapped AcV1 epitope were substituted with a c-Myc epitope and the resulting construct was used to replace wt GP64 in recombinant AcMNPV viruses, the modified GP64 protein appeared to function normally. However, an anti-c-Myc monoclonal antibody did not neutralize infectivity of those viruses. Because binding of the c-Myc MAb to the same site in the GP64 sequence did not result in neutralization, these studies suggest that AcV1 neutralization may result from a specific structural constraint caused by AcV1 binding and not simply by steric hindrance caused by antibody binding at this position in GP64.     

Monoclonal antibody against pertussis toxin: effect on toxin activity and pertussis infections.

Antibody-producing hybridomas of myeloma SP2/O and spleen cells of BALB/c mouse immunized with pertussis toxoid and pertussis toxin were selected by the binding ability of the monoclonal antibody to the subunit protein of the toxin. Two monoclonal antibodies, 1B7 and 3F10, specific for a subunit which has no binding activity to haptoglobin and sheep erythrocytes, named S1, and one antibody, 1H2, for a subunit related to the binding activity of the pertussis toxin molecule to haptoglobin or sheep erythrocytes, named S4, were examined for mouse protective activity against pertussis infection. Antibody 1B7 not only neutralized leukocytosis-promoting and islet-activating activities of the toxin but also protected mice against intracerebral and aerosol challenge with Bordetella pertussis. The antibody, furthermore, showed therapeutic effects on mice showing severe clinical signs with pertussis infection. The other two antibodies, 3F10 and 1H2, showed neither neutralizing nor protecting activity, nor significant synergistic effects on antibody 1B7.