Potentiation of cytotoxicity against a CEA positive cell line by the bispecific antibody OH1 using LAK cells from cancer-bearing patients.

Bispecific antibody, OH1 was developed, which simultaneously recognizes CD3 on T cells and carcinoembryonic antigen (CEA) on tumor cells. Although there was not significant difference, PBMCs pretreated with OH1 showed tendency to prolong survival of KATO III-injected SCID mice compared with control groups. although cytotoxicity of LAK cells from cancer-bearing patients was suppressed compared with that of cells of healthy donors, LAK cells from the patients pretreated with OH1 showed significantly increased cytotoxicity against KATO III cells. These results suggest that OH1 could be useful in immunotherapy with LAK cells for carcinomas that express CEA on the membrane.