REPLICATION OF HUMAN CYTOMEGALOVIRUS IN CELLS DEFICIENT IN BETA(2)-MICROGLOBULIN GENE-EXPRESSION

To study the roles of beta(2)-microglobulin (beta(2)-m) and major hist ocompatibility complex (MHC) class I expression in human cytomegalovir us (HCMV) infection, the ability of HCMV strain AD-169 to infect and r eplicate in a human melanoma cell line (FO-1), which is beta(2)-m-defi cient and cannot express MHC class I on its cell surface, was examined . Susceptibility of FO-1 cells was compared with human foreskin fibrob lasts (HFF) and FO-1H cells (FO-1 cells that have been transfected wit h the human beta(2)-m gene, restoring MHC I expression on the cell sur face). As judged by the HCMV immediate early 1 (IE-1) antigen expressi on, HCMV was able to infect FO-1 cells, although somewhat less efficie ntly than HFF. However, the expression of HCMV late (L) antigen and th e production of virus was significantly less for FO-1 cells than for H FF. Analysis of the FO-1H transfectants revealed that expression of IE -1 and L HCMV antigens was comparable to FO-1 cells, which lack MHC I. Treatment of FO-1 and FO-1H cells with sodium butyrate prior to inocu lation did not alter the expression of MHC I in either cell type, but did increase susceptibility of both cell types to HCMV infection, as w ell as the expression of L antigens and production of virus. These stu dies indicate that HCMV infection of FO-1 cells is independent of beta (2)-m and MHC class I expression.