AbstractThe role of the oligosaccharide portions of cell surface glycoproteins in the susceptibility of virus‐infected cells to H‐2‐restricted cytolysis was investigated by using the antibiotic tunicamycin (TM). TM inhibits the addition of sugars to the polypeptides of glycoproteins. TM treatment of P 815 cells before and during infection with vesicular stomatitis virus (VSV) inhibited glycosylation of proteins and reduced by about 50% the lysis of infected P 815 cells by VSV‐immune, H‐2‐identical killer cells. In contrast, TM treatment had a modest inhibitory effect on cytolysis of P 815 cells by alloimmune effector cells. TM treatment did not inhibit the surface expression of either H‐2 or VSV glycoprotein. Thus, glycosylation of H‐2 and/or viral glycoprotein is a prerequisite for the lysis of infected cells by H‐2‐identical, VSV‐i