Differential effect of adenovirus 2 E3/19K glycoprotein on the expression of H-2Kb and H-2Db class I antigens and H-2Kb- and H-2Db-restricted SV40-specific CTL-mediated lysis.

The E3/19-kDa glycoprotein (E3/19K) coded by adenovirus type 2 (Ad2) is known to inhibit the cell-surface expression of major histocompatibility complex (MHC) class I antigens by binding to the MHC antigens intracellularly, and thus reduces recognition of antigens by MHC-restricted cytotoxic T lymphocytes (CTL). We have studied the effect of the E3/19K expression in SV40-infected monkey cells, TC-7/H-2Kb and TC-7/H-2Db expressing transfected H-2Kb and H-2Db antigens, respectively, on the cell-surface H-2 class I antigens and on lysis of the cells by SV40 large tumor (T)-antigen-specific H-2Kb- and H-2Db-restricted CTL clones. H-2Db antigen expression on TC-7/H-2Db cells was drastically reduced by infection with Ad2 but not with an E3/19K-negative SV40-Ad2 hybrid virus, Ad2+ND1, as early as 12 hr postinfection. However, H-2Kb antigen expression on Ad2-infected TC7/H-2Kb cells remained unaltered, even at 24 hr postinfection. Specific lysis of SV40-infected TC-7/H-2Db cells by H-2Db-restricted SV40 T-antigen-specific CTL clones, Y-1 and Y-3, was strongly reduced by coinfection of the target cells with Ad2 but not with Ad2+ND1. Lysis of SV40-infected TC-7/H-2Kb cells by a H-2Kb-restricted SV40 T-antigen-specific CTL clone Y-4 was also reduced significantly by Ad2 infection, but not Ad2+ND1. These results indicate that the E3/19K protein affects cell-surface expression of H-2Db antigen but not H-2Kb antigen.