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Identification of an FMR cell surface antigen associated with murine leukemia virus-infected cells
Abstract:
FMR antigens are found on the surface of cells infected with Friend, Moloney, and Rauscher murine leukemia viruses (MuLV). These antigens are serologically distinct from the G cell surface antigens that are found on cells infected with endogenous MuLV (AKR and Gross virus). Cell surface antigens of both virus groups are immunogenic in mice, and immunization with appropriate virus-infected cells leads to the production of cytotoxic antisera. The cytotoxic activity of FMR antisera can be absorbed by disrupted preparations of Rauscher MuLV, but not by AKR MuLV. FMR antisera precipitate the viral envelope proteins gp70, pl5(E), and p12(E) from detergent-disrupted preparations of [3H]leucine-labeled MuLV. The reaction of these antisera with p15(E) and p12(E) proteins is directed against group-specific antigens and can be absorbed with AKR MuLV; in contrast, the reaction of these antisera with gp70 is directed against type-specific antigens and is absorbed only by viruses of the FMR group. In immune precipitation assays with detergent-disrupted 125I surface-labeled cells, FMR antisera react only with type-specific antigens of the viral envelpe protein. On the basis of these findings we conclude that the FMR cell surface antigen is a determinant on the MuLV env gene product.
Insights
FMR antigens on cells infected with murine leukemia viruses (MuLV) are distinct from G cell surface antigens. These FMR antigens are type-specific determinants on the MuLV envelope protein, crucial for viral identification.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Murine leukemia viruses (MuLV) induce distinct cell surface antigens.
- FMR antigens are present on cells infected with Friend, Moloney, and Rauscher MuLV.
- G cell surface antigens are associated with endogenous MuLV (AKR, Gross virus).
Purpose of the Study:
- To serologically characterize FMR antigens.
- To determine the viral components recognized by FMR antisera.
- To elucidate the nature of the FMR cell surface antigen.
Main Methods:
- Immunization of mice with virus-infected cells to produce cytotoxic antisera.
- Absorption assays using disrupted MuLV preparations.
- Immune precipitation of viral proteins from labeled MuLV and cells.
Main Results:
- FMR antisera exhibit cytotoxic activity against MuLV-infected cells.
- FMR antisera precipitate gp70, p15(E), and p12(E) viral proteins.
- gp70 is recognized by type-specific determinants, while p15(E) and p12(E) involve group-specific determinants.
Conclusions:
- FMR cell surface antigen is a type-specific determinant on the MuLV envelope (env) gene product.
- Distinguishes between exogenous (FMR) and endogenous (G) MuLV antigen groups.
- Provides insights into MuLV-host interactions and viral protein characterization.