Differential regulation of HLA-DR mRNAs and cell surface antigens by interferon.

Abstract

Human interferons‐alpha, ‐beta and ‐gamma enhance HLA‐DR mRNAs in all the human lymphoblastoid and melanoma cell lines studied. The increase concerns both alpha and beta chain mRNAs. Moreover, we show that immune interferon‐gamma preferentially enhances class II MHC mRNA. This effect of IFN‐gamma on the synthesis of alpha and beta HLA‐DR chains has been also analysed by immunoprecipitation. It is abolished by a monoclonal antibody directed against human IFN‐gamma. The effect of interferon on the cell surface level of HLA‐DR molecules does not always correspond to the enhancement of HLA‐DR mRNA. Our experiments suggest that this discrepancy between the enhancement of HLA‐DR mRNA and cell surface antigen might be due to a constitutively high level of the corresponding antigens on several of the human cells studied.