Antitumor effects of L6, an IgG2a antibody that reacts with most human carcinomas.

Mouse monoclonal antibody L6 (IgG2a subtype) recognizes a ganglioside antigen expressed at the surface of cells from human non-small-cell lung carcinomas, breast carcinomas, and colon carcinomas. We now show that this antibody can lyse L6 antigen-positive human tumor cells in the presence of Leu-11b-positive human lymphocytes (i.e., mediate antibody-dependent cellular cytotoxicity) or human serum (mediate complement-dependent cytotoxicity) and that it can inhibit the outgrowth of an L6 antigen-positive human tumor transplanted onto nude mice.