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T lymphocyte function as the principal target of lymphocytic choriomeningitis virus-induced immunosuppression
Abstract:
Plaque-forming cell responses against sheep erythrocytes, Escherichia coli lipopolysaccharide, pneumococcal polysaccharide, and polyvinylpyrrolidone were examined in mice infected with lymphocytic choriomeningitis virus. A 92 to 96 percent reduction of the thymus-dependent anti-sheep erythrocyte responses was observed 2 to 4 weeks after infection. However, the thymus-independent responses against the three other antigens were close to normal at all stages of the infetion. Studies on allograft immunity of infected C3H mice against DBA/2 mastocytoma cells revealed a severe suppression of the T cell-mediated cytotoxic response which was temporally related to the impaired humoral responsiveness against sheep erythrocytes. The capacity of spleen cells from infected mice to restore immune responsiveness of lethally irradiated recipients against sheep erythrocytes was significantly reduced. The adoptive responses, however, were clearly improved when normal thymus cells were added to the inferior spleen cells. Moreover, it appeared that the spleen cells from immunosuppressed donor mice could not confer suppression to normal lymphoid cells. The presented findings are consistent with the assumption that a numeric deficiency of T cells, or cells belonging to some T cell subpopulation, is the primary cause of lymphocytic choriomeningitis virus-induced immunosuppression.
Insights
Lymphocytic choriomeningitis virus infection severely impairs thymus-dependent immune responses in mice. This immunosuppression is linked to a numerical deficiency in T cells, affecting cell-mediated immunity.
Area of Science:
- Immunology
- Virology
- Cell Biology
Background:
- Lymphocytic choriomeningitis virus (LCMV) is a known immunosuppressive pathogen.
- Understanding the mechanisms of viral-induced immunosuppression is crucial for managing opportunistic infections in immunocompromised individuals.
Purpose of the Study:
- To investigate the impact of LCMV infection on different types of immune responses in mice.
- To elucidate the cellular basis of LCMV-induced immunosuppression.
Main Methods:
- Mice infected with LCMV were assessed for plaque-forming cell responses against thymus-dependent (sheep erythrocytes) and thymus-independent antigens (E. coli lipopolysaccharide, pneumococcal polysaccharide, polyvinylpyrrolidone).
- Allograft immunity and T cell-mediated cytotoxicity were evaluated.
- Spleen cell activity in restoring immune responses in irradiated recipients was examined, with and without added normal thymus cells.
Main Results:
- LCMV infection caused a significant reduction (92-96%) in thymus-dependent anti-sheep erythrocyte responses.
- Thymus-independent responses remained largely unaffected.
- T cell-mediated cytotoxic responses against allografts were severely suppressed.
- Spleen cells from infected mice showed reduced capacity to restore immunity, an effect ameliorated by adding normal thymus cells.
Conclusions:
- LCMV infection induces profound immunosuppression primarily affecting thymus-dependent and T cell-mediated immunity.
- Findings suggest a numerical deficiency of T cells or a specific T cell subpopulation is the main cause of LCMV-induced immunosuppression.
- This highlights the critical role of T cells in orchestrating effective adaptive immunity against viral challenges.