The role of gp⁷⁰ in the target antigen recognized by murine leukemia virus immune cytotoxic T‐lymphocytes

Abstract

'The role of the murine leukemia virus (MLV) envelope glycoprotein, gp70, in the formation of the target antigen recognized by in vivo generated MLV-immune cytotoxic T-lymphocytes (FMR-MLV immune TJ was studied. Treatment of the Rauscher MLV-transformed C57BU6 target cell, RBL-5, for 4 h with the protein glycosylation inhibitor tunicamycin, was found to render the cells resistant to lysis by FMR-MLV immune T, while lysis of the tunicamycin-treated RBL5 cells by allogeneic H-Zb immune T, was not decreased. This failure of FMR-MLV-immune T, to lyse tunicamycintreated RBL-5 cells correlated with an inhibitory effect of tunicamycin on the synthesis of gp70, resulting from impaired glycosylation of the gp70 precursor, gpPr90. Yet, examination of the tunicamycin-treated RBL-5 cell surface by lactoperoxidase '251 iodination and immunoprecipitation techniques, revealed (I) that neither unglycosylated gp70 nor gpPr90 antigens were detectable and (2) that the gp70 antigens from tunicamycin-treated and untreated RBLS cells were identical in their (I) migration pattern in SDS polyacrylamide gel electrophoresis (SDS PAGE) (2) isoelectric focusing profiles on a pH 3.5 -pH 10 gradient and (3) external, lactoperoxidase accessible, '151 peptides. Further, tunicamycin-treated RBL5 cells retained 33 % -50 % of their Rauscher MLV gp70 expression, as determined by quantitative absorption of a goat anti-Rauscher MLV gp70 serum. When this latter result was interpreted with reference t o the study by Lesley e t a/. (l974), who observed a linear relationship between the amount of alloantigen expressed and susceptibility t o immune T, killing, it was concluded that this quantitative change in gp70 expression could not adequately account for the failure of FMR-MLV immune T, to lyse tunicamycin-treated RBL-5 cells. It is therefore proposed that an MLV-induced antigen other than gp70 may be recognized on RBL-5 cells by FMR-MLV immune T, .

Tunicamycin Inhibits Diabetes

“…Tunicamycin inhibits the synthesis of all N-linked glycoproteins (N-glycans) and causes cell cycle arrest in 596 the G1 phase. In addition, it is used in biology as an experimental tool that induces an unfolded protein response [6][7][8][9][10][11].…”