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Mouse fibroblasts transformed by Rous sarcoma virus express a virus-specific non-virion transplantation antigen
Abstract:
Rous sarcoma virus (RSV)-transformed fibroblasts from different animals species a serologically detectable virus-induced non-virion cell surface antigen (VCSA), whose expression is controlled by the transforming viral src gene and by a cellular gene. Now, by in vivo immunization, we have found that RSV-transformed fibroblasts from different mouse strains share a virus-specific transplantation antigen. In fact, only animals immunized with irradiated syngeneic or allogeneic fibroblasts transformed by RSV, but not animals immunized with cells transformed by different oncogenic agents, rejected a lethal dose of syngeneic RSV-induced tumor cells. Immunoprecipitation tests with monospecific antisera showed that the expression of this antigen did not correlate with the presence of intracellular viral proteins other than the src gene product pp60src. However, hyperimmunization of mice with hamster or quail fibroblasts transformed by RSV, that express a high level of pp60src, did not induce transplantation resistance. It is concluded that the expression of both the serologically-defined VCSA and the transplantation antigen is the result of the interaction of pp60src with host cell gene product(s) rather than the simple exposure of pp60src at the outer cell surface.
Insights
Rous sarcoma virus (RSV) infection induces a unique cell surface antigen (VCSA) and transplantation antigen in fibroblasts. These antigens result from the interaction of the viral src gene product pp60src with host cell factors, not just viral protein exposure.
Area of Science:
- Oncology
- Virology
- Immunology
Background:
- Rous sarcoma virus (RSV)-transformed fibroblasts express a virus-induced non-virion cell surface antigen (VCSA).
- VCSA expression is regulated by the transforming viral src gene and a cellular gene.
Purpose of the Study:
- To investigate the nature of virus-specific transplantation antigens induced by RSV in fibroblasts.
- To determine the relationship between VCSA, transplantation antigens, and the viral src gene product pp60src.
Main Methods:
- In vivo immunization of different mouse strains with irradiated RSV-transformed fibroblasts.
- Challenging immunized animals with lethal doses of syngeneic RSV-induced tumor cells.
- Immunoprecipitation assays using monospecific antisera to detect viral proteins, including pp60src.
Main Results:
- RSV-transformed fibroblasts from different mouse strains share a virus-specific transplantation antigen.
- Animals immunized with RSV-transformed cells rejected lethal tumor cell doses, unlike those immunized with cells transformed by other oncogenic agents.
- Antigen expression correlated with the src gene product pp60src but not other intracellular viral proteins.
- Hyperimmunization with RSV-transformed cells from other species (hamster, quail) expressing high pp60src did not induce transplantation resistance.
Conclusions:
- Both serologically-defined VCSA and the transplantation antigen are products of pp60src interacting with host cell gene products.
- These antigens are not simply due to the exposure of pp60src on the cell surface.