Amplification of the expression of major histocompatibility class I antigens by inducers of differentiation and gamma interferon in murine and human solid tumor cell lines

Treatment of B16 F10-9 mouse melanoma cell line and RC-29 human renal carcinoma cell line with chemical inducers of differentiation such as sodium butyrate (SB) hexamethylene bisacetamide (HMBA) and L-histidinol significantly increased the expression of major histocompatability complex (MHC) class I antigens. This effect depends on the continued exposure of the cells to these materials. Combined treatment of the B16 F10-9 melanoma cells with recombinant murine gamma interferon and SB increased the expression of MHC class I antigens in a synergistic manner. This effect of chemical inducers of differentiation might be of importance in rendering tumor cells more sensitive to the immune defense mechanisms.