[Cloning of anti-breast cancer monoclonal antibodies from phage antibody libraries].

Rodent monoclonal antibodies (McAbs) with anti-tumor specificity can be isolated from hybridomas by screening reactivity against tumor cells. Here, as an approach to bypass hybridoma technology, we attempted to isolate anti-tumor rodent McAbs directly from phage antibody libraries. We first used RT-PCR reactions to amplify diverse repertoires of heavy (Fd part) and light chains from spleen lymphocytes of Balb/c mice immunized with human cancer cell line BCap37 and then, by recombination of the repertoires in bacteria, generated a repertoire (1.0 x 10(7)) of Fab fragments displayed on filamentous phage. Four rounds of selection against living cancer cells showed specific enrichment of phage antibodies. After the fourth round of selection 174 out of 182 clones exhibited cancer cell binding capacity. The specificity of those clones was verified by reactivity against 12 human tumor cell lines, human lymphocytes and fibroblasts. In the production of monoclonal antibodies toward human cancer, this strategy may provide an alternative approach, and even surpass the hybridoma technology.