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Murine leukemia virus-associated cell surface antigens in rats neonatally infected with Gross murine leukemia virus
Abstract:
The inoculation of newborn W/F, Lew, AS and DA rats with Gross murine leukemia virus (G-MuLV) resulted in the prompt appearance of cells with viral protein antigens (VPA) on their surfaces. These were first found in the bone marrow and spleen and later in the thymus gland. As the animals developed, the VPA-positive population expanded and the intensity of the fluorescence increased. In the spleen, the cells with the strongest fluorescence had the properties of T-cells, but in both spleen and bone marrow low levels of VPA were found on non-T-cells. The VPA-positive population expanded long before malignant cells could be detected and, in most animals, the entire T-cell compartment became antigen-positive. These animals were unable to respond to G-MuLV antigens and many eventually developed leukemia. However, some animals apparently broke the tolerance that followed neonatal infection and eliminated VPA-positive cells from their tissues
Insights
Neonatal infection with Gross murine leukemia virus (G-MuLV) in rats led to widespread viral protein antigen (VPA)-positive cells, causing immune tolerance and leukemia. Some rats overcame this tolerance, eliminating VPA-positive cells.
Area of Science:
- Immunology
- Virology
- Oncology
Background:
- Neonatal exposure to viruses can induce immune tolerance.
- Gross murine leukemia virus (G-MuLV) is known to cause leukemia in rodents.
Purpose of the Study:
- To investigate the early immunological effects of neonatal G-MuLV infection in rats.
- To determine the fate of viral protein antigen (VPA)-positive cells following infection.
Main Methods:
- Inoculation of newborn rats (W/F, Lew, AS, DA strains) with G-MuLV.
- Flow cytometry and immunofluorescence to detect VPA on cell surfaces.
- Characterization of VPA-positive cells (T-cells vs. non-T-cells).
Main Results:
- VPA-positive cells rapidly appeared in bone marrow, spleen, and thymus after G-MuLV inoculation.
- The VPA-positive cell population expanded, with T-cells showing the strongest fluorescence.
- Neonatal infection induced tolerance to G-MuLV antigens, leading to leukemia in most rats.
- A subset of rats developed tolerance and cleared VPA-positive cells.
Conclusions:
- Early G-MuLV infection establishes widespread VPA expression and immune tolerance.
- Tolerance can be broken, allowing for the elimination of infected cells and potentially preventing leukemia.