Production and the characterization of monoclonal antibody against CD43, K06

A monoclonal antibody against human CD43 has been developed and designated as K06. Its reactivity in the lymphoid organs was different from that of known anti-CD43 monoclonal antibodies suggesting that this may recognize a novel epitope of human CD43 molecule. The CD43 epitope detected by anti-K06 monoclonal antibody was highly expressed in cortical thymocytes, platelets, and myeloid cells of normal peripheral blood, and its reactivity was comparable to that of known anti-CD43 monoclonal antibodies. However, the density of this epitope was lower in the medullary thymocytes. Biochemical studies indicated that anti-K06 monoclonal antibody could recognize glycosylated moiety of CD43 antigen. The expression profile of anti-K06 monoclonal antibody in several cell lines was somewhat different from that of known anti-CD43 antibodies. In addition, CD43 ligation through the K06 epitope appeared to induce apoptosis in human leukemic cell line, Molt-4. We therefore assume that K06 epitope of human CD43 might have some role in T-cell development.