| Popis: |
Human monoclonal antibodies specific for platelet membrane glycoproteins (GPs) arepotentially important reagentsfor studies of the immunogenicity of membrane glycoproteins. A human monoclonalautoantibody, 5E5, reactive with plateletGPIIIa has been developed (Nugent, et al.,Blood, 1987, in press). In this report, we describe the production of additional human monoclonal antibodies specific for GPIIIa. Peripheral blood lymphocytes fromone patient with post-transfusion purpur(PTP) and one woman who had delivered an infant with neonatal alloimmune thrombocytopenic purpura (NATP) were used as a source of antigen-specific lymphocytes. A B-lympho-cyte-enriched population was transformed with Epstein Barr virus, strain B95-8, and cultured in microtiter plates. After two weeks, culture supernatants were screened by an antigen-capture ELISA wherein murine monoclonal antibody specificfor the GPIIb-IIIa complex was used to holdcorresponding antigen from a lysate ofnormal platelets. B-lymphoblastoid cell lines producing IgG and/or IgM antibodies were expanded and either cloned by limiting dilution technqiue or hybridized with a HAT-sensitive, ouabain-resistant heterohybrid fusion line, F6, using polyethylene glycol. Hybridomas were selected in medium containing HAT andouabain. After twoweeks, hybridomas producing anti-GPIIb and/or anti-GPIIIa antibody were cloned by limiting dilution. Culture supernatants from cloned B-lymphoblastoid cell lines and cloned hybridomas were rescreened by ELISA wherein affinity-purified GPIIIa or other platelet GP weredirectly conjugatedto microtiter plates. One IgM antibody produced by acloned B-lymphoblastoid cellline (CH16) andtwo IgG antibodies produced bycloned hybridomas(Del5.19 and Del5.23) were shownto react with GPIIIa but not other GP. Further characterization of these human monoclonal antibodies, produced continuouslyin culture now for four months, is in progress. |
