| Abstract: | ![]()
The nature of the target antigen, expressed on murine sarcoma virus (MSV) and related murine tumors which reacts with T killer lymphocytes, remains ill-defined. The experiments reported here show that: (a) the previously described H-2 restriction phenomenon is found under all experimental conditions including 3–4 and 16–20-h chromium release tests. With 16–20 h tests and highly efficient T lymphocytes however, quantitative methods are necessary to demonstrate the H-2 restriction. These results support the hypothesis that H-2 molecules may be determinant in the structure and/or in the function of the cytolytic T lymphocyte (CTL) reactive antigen. (b) Under syngeneic conditions (i.e. using H-2-identical immune lymphocytes, stimulators and target cells), the pattern of specificities recognized by anti-MSV or anti-Friend T killer cells on 20 different lymphomas suggests that the main reactive antigen is an “FMR-like” substance. Identical conclusions were drawn from competition experiments. (c) Blockings were obtained by pre-incubation of the target cells with a goat anti-gp70, suggesting a possible role of the viral gp70 in the antigen recognized. However, this could be due to nonspecific reactions as two other anti-gp70 sera as well as with antisera directed against the viral components gp45, pr60, p30, p15, p12 and p10 did not block. The CTL/tumor cell interaction was not inhibited by virion-associated antigens added to the medium. Lysostrip and co-capping experiments have failed to reveal an association between H-2 and gp70. The nature of the viral protein bearing the “FMR-like” substance therefore remains to be established. |
