THE EFFECT OF ALPHA-INTERFERON AND GAMMA-INTERFERON ON CELL-GROWTH AND HISTOCOMPATIBILITY ANTIGEN EXPRESSION BY HUMAN RENAL-CARCINOMA CELLSIN-VITRO

Tumour cells were separated from 19 renal carcinomas and cultured in v itro. The effect of interferon (IFN) alpha and gamma on cell prolifera tion was measured and compared to the effect of IFN on the expression of class I and class II major histocompatibility complex (MHC) antigen s. When tested within the first 14 days of culture, IFN-alpha inhibite d protein synthesis in 12 of 15 and IFN-gamma in four of nine tumours. Reduction in cell counts was in parallel. In six tumours the culture period was extended and in all six the effect of IFN-alpha was lost. E xposure to IFN-alpha induced or enhanced class I antigen expression in eight of 19 tumours and class II expression in two of 19. The analogo us figures for IFN-gamma were five and three tumours. In four of five cases where a comparison could be made there was a correlation between the effects of IFN-alpha on cell proliferation and class I antigen ex pression. The efficacy of IFN in the treatment of renal carcinomas may thus, in part, result from inhibition of cell proliferation and enhan cement of antigen expression.