Human bifunctional antibody generated by heterologous association of heavy and light chains.

Hybrid antibodies, including bifunctional antibody, were obtained by fusing two different drug-resistant clones of human hybridomas HB4C5 and SU-1. One hybridoma, producing human IgM-class monoclonal antibody reactive to porcine carboxypeptidase A (Cpase), was a 6-thioguanine resistant clone (6T-C5) of HB4C5 cell line. Another, secreting human IgM-class anti-double-stranded DNA (ds DNA) monoclonal antibody, was a 5-bromodeoxyuridine resistant clone (5B-SU) of SU-1. Hybrid hybridomas were generated by fusing the 6T-C5 and 5B-SU lines and screened by HAT selection. Among many hybrid hybridomas, A9C11 cells produced bifunctional antibody having dual specificity for Cpase and ds DNA, and the light chains of the antibody consisted of the only ones derived from 5B-SU antibody, indicating that bifunctional antibody could be generated by heterologous association of heavy and light chains.