Expression of H-2 and viral antigens and resistance to the antitumor lysis of tunicamycin-treated MBL-2 lymphoma cells.
The role of protein glycosylation in the tumor lysis mediated by effector cells derived from Moloney-sarcoma-virus(MSV)-immune mice was studied. Treatment of the Moloney-virus-induced H-2b lymphoma target cells, MBL-2, with tunicamycin (TM), an inhibitor of the protein-N-linked glycosilation, was found to cause a loss of susceptibility to lysis by MSV-immune syngeneic effectors cells, while the same target cells remained fully sensitive to the lytic action of anti-H-2b-immune lymphocytes. Examination of MBL-2 cell surface by lactoperoxidase, 125I iodination, and immunoprecipitation by antiviral protein sera revealed that env but not gag viral gene-encoded products were expressed on the surface of this lymphoma. The TM-induced alteration of cell surface expression of H-2Db, H-2Kb, and gp70 antigens was examined by a combined approach of serological and biochemical techniques. The results were concordant in indicating that (1) after 16 h of TM treatment the cells showed a decreased expression of the three glycoproteins, (2) H-2Db (the restriction element in this system) resulted more affected by the treatment than its counterpart H-2Kb (75% vs 50% reduction as compared to untreated cells), (3) an additional lighter form of H-2Kb was found on the surface of TM-treated cells. In the context of an "associative recognition' of Db and gp70 by MSV-immune effector cells, our results may explain the loss of susceptibility to antitumor effectors of TM-treated MBL-2 cells by a quantitative reduction in the expression of both molecules which interact to create the target structure of syngeneic effectors.
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis* / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000276:immunology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects*; D006183:H-2 Antigens / Q000032:analysis* / Q000235:genetics; D008223:Lymphoma / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008979:Moloney murine leukemia virus / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014415:Tunicamycin; D014759:Viral Envelope Proteins / Q000032:analysis / Q000276:immunology
D000956:Antigens, Viral; D006183:H-2 Antigens; D014759:Viral Envelope Proteins; D014415:Tunicamycin