RESUMO
A study was made of the stability of the murine bispecific trinoma OC/TR with respect to secretion of both types of parental heavy and light chains. OC/TR is a cell line producing bispecific antibody that reacts with the CD3 antigen on T cells and the folate-binding receptor--frequently found to be overexpressed on ovarian carcinoma cells. Of the 10 different IgG combinations theoretically possible with 2 heavy and 2 light chains, 6 combinations were secreted. Subclones varied considerably in relative production of the two parental heavy and light chains. A detailed analysis was made of the binding characteristics and retargeting activity of each of the IgGs produced. From a clone producing a relatively high quantity of bispecific IgG, a large-scale production was initiated. The purification of clinical grade bispecific F(ab')2 from harvest fluids is described. The yield from this purification process was found to be comparable to the yield of bispecific F(ab')2 after chemical cross-linking of two different Fab'.
Assuntos
Anticorpos Biespecíficos/imunologia , Anticorpos Antineoplásicos/imunologia , Complexo CD3/imunologia , Proteínas de Transporte/imunologia , Fragmentos Fab das Imunoglobulinas/imunologia , Proteínas de Neoplasias/imunologia , Neoplasias Ovarianas/imunologia , Receptores de Superfície Celular , Animais , Anticorpos Biespecíficos/isolamento & purificação , Anticorpos Antineoplásicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Feminino , Receptores de Folato com Âncoras de GPI , Humanos , Hibridomas/imunologia , Fragmentos Fab das Imunoglobulinas/isolamento & purificação , Imunoglobulina G/imunologia , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias Leves de Imunoglobulina/imunologia , Camundongos , Linfócitos T/imunologiaRESUMO
We isolated a monoclonal antibody that immunoprecipitated two proteins of 22 and 27 kilodaltons (kDa) from nononcogenic adenovirus type 5 early region 1 (E1)-transformed rat cells but not from oncogenic adenovirus type 12 E1-transformed rat cells. In a variety of adenovirus-transformed cells including cells transformed by E1A and the c-H-ras oncogene, we found a perfect, inverse correlation between the presence of these two proteins and the oncogenicity of these cells in syngeneic immunocompetent rats. Characterization of the two proteins revealed that they occur in a large (700-kDa) complex and that the 27-kDa protein is identical to the already known 27-kDa (28-kDa) heat shock protein hsp27. The suppression of the hsp27 protein in oncogenic cells is further demonstrated by the fact that its mRNA is absent even after heat-shock induction.