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Immune response to oncornaviruses and tumor-associated antigens in the chicken
Abstract:
Two principal virus-directed antigens have been identified on the surface of oncornavirus-infected chick embryo cells. One is identical with the major virus type-specific envelope antigen, which is a glycoprotein with a molecular weight of 85,000. The 2nd antigen (tumor-specific cell surface antigen) is specific for transformed cells, i.e., absent from productively infected but nontransformed cells. This antigen has been identified as a glycoprotein with a molecular weight of 100,000 and was not found in the mature virion. Remarkably, both antigens induce humoral as well as cellular immunity in the chicken. It could be shown that cells can be killed in cytotoxic assays via either the tumor-specific cell surface antigen or the virus envelope glycoprotein alone.
Insights
Two main oncornavirus antigens were found on infected cells: a virus envelope glycoprotein and a tumor-specific cell surface antigen. Both trigger immune responses in chickens, enabling targeted cell killing.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Oncornaviruses can infect chick embryo cells, leading to the expression of viral antigens on the cell surface.
- Understanding these antigens is crucial for developing diagnostic and therapeutic strategies against virus-induced transformations.
Purpose of the Study:
- To identify and characterize virus-directed antigens on oncornavirus-infected chick embryo cells.
- To investigate the immunogenicity of these antigens and their role in cellular immunity.
Main Methods:
- Identification of cell surface antigens using immunological assays.
- Characterization of antigens by molecular weight and presence in virions.
- Assessment of humoral and cellular immune responses in chickens.
- Cytotoxic assays to evaluate cell killing mediated by specific antigens.
Main Results:
- Two principal virus-directed antigens were identified: a major virus type-specific envelope glycoprotein (85,000 MW) and a tumor-specific cell surface antigen (100,000 MW).
- The tumor-specific antigen was found only on transformed cells and not in mature virions.
- Both identified antigens elicited humoral and cellular immunity in chickens.
- Cytotoxic assays demonstrated that cells could be killed by targeting either the tumor-specific antigen or the virus envelope glycoprotein.
Conclusions:
- Oncornavirus infection induces distinct cell surface antigens that are immunogenic in chickens.
- The virus envelope glycoprotein and the tumor-specific cell surface antigen can independently mediate cell killing, suggesting potential for targeted immunotherapies.