Abrogation of cell surface expression of @entity1 class I transplantation antigens by an adenovirus protein in XXXX oocytes.

@entity1 @entity2262 @entity1238 @entity1735
Class I transplantation antigens form complexes with a virus protein encoded in the early region E3 of the adenovirus-2 genome. The interaction between this viral glycoprotein, E19, and nascent @entity1 class I antigens has been examined by microinjecting purified mRNA into @entity1238 oocytes. Both E19 and the two class I antigen subunits, the heavy chain and @entity2262 ( @entity2262 ), were efficiently translated. The heavy chains did not become terminally glycosylated, as monitored by endoglycosidase H digestion, and were not expressed on the oocyte surface unless they were associated with @entity2262 . The E19 protein did not become terminally glycosylated, and we failed to detect this viral protein on the surface of the oocytes. Co-translation of heavy chain and E19 mRNA demonstrated that the two proteins associate intracellularly. However, neither protein appeared to be transported to the trans-Golgi compartment. Similar observations were made in adenovirus-infected HeLa cells. Heavy chains bound to @entity2262 became terminally glycosylated in oocytes in the presence of low concentrations of E19. At high concentrations of the viral protein, no @entity1735 modifications and no cell surface expression of class I antigens were apparent. Thus, @entity2262 and E19 have opposite effects on the intracellular transport of the heavy chains. These data suggest that adenovirus-2 may impede the cell surface expression of class I antigens to escape immune surveillance.
