CHANGES OF ANTIGEN EXPRESSION ON HUMAN HEPATOMA-CELL LINES CAUSED BY SODIUM-BUTYRATE, A DIFFERENTIATION INDUCER

We have previously reported the effect of a differentiation inducer, sodium butyrate (SB), on human hepatocellular carcinoma (HCC) cell lines, demonstrating that it was a potent inducer of differentiation. In the present study, we investigated the alteration in expression of an antigen defined by a murine monoclonal antibody, H2, as well as alterations in the expression of other antigens, on the HCC cell lines HCC-T, HCC-M, and PLC/PRF/5, since it is known that specific antigenic changes occur during the differentiation of leukemic cells. The expression of the antigen defined by H2 increased immunocytochemically on HCC-T, HCC-M, and PLC/PRF/5 during treatment with SB. A flowcytometric study showed that almost all the HCC-T and HCC-M cells treated with SB highly expressed this antigen after 5 days' treatment. The antigen expression detected by H2 decreased after the removal of SB from the medium. On the other hand, antigen expression detected by another monoclonal antibody, 5C11, was not changed by this treatment. The expression of intracellular adhesion molecule (ICAM)-1 in HCC-T increased slightly, but that of beta2-microglobulin and HLA-DR did not change. These results demonstrated that some antigen expression was changed by SB treatment and that the antigen defined by H2 seemed to be highly expressed on human HCC cells in the differentiated state.