Use of silica to identify host mechanisms involved in suppression of established Friend virus leukemia
Abstract:
Silica, an agent predominantly toxic for macrophages, inoculated i.v. to Friend leukemia virus (FLV)-infected mice, blocks the FLV-leukemosuppressive effects of chlorite-oxidized oxyamylose (COAM)-statolon treatment. FLV-infected, COAM-statolon-treated mice that have received silica and have failed to suppress FLV leukemia produced normal amounts of interferon, but did not make antibodies cytotoxic for FLV leukemic cells. Transfer of untreated spleen cells, splenic T cells, or thymocytes from mice with suppressed FLV erythroleukemia to FLV-infected mice treated with silica and COAM-statolon restores the humoral immune response to FLV antigens and results in leukemosuppression. Thus, T lymphocytes from mice with suppressed erythroleukemia participate in FLV leukemosuppression either directly as effector cells, or indirectly as helper cell in the production of antibodies to FLV antigens.
Insights
Silica blocks chlorite-oxidized oxyamylose (COAM)-statolon
Area of Science:
- Immunology
- Virology
- Oncology
Background:
- Friend leukemia virus (FLV) infection causes immunosuppression.
- Chlorite-oxidized oxyamylose (COAM)-statolon is a potential therapeutic agent for FLV leukemia.
- Silica is known to be toxic to macrophages, key immune cells.
Purpose of the Study:
- To investigate the role of silica in modulating the immune response to Friend leukemia virus (FLV).
- To understand the mechanism by which COAM-statolon exerts its leukemosuppressive effects.
- To determine the involvement of T lymphocytes in FLV leukemosuppression.
Main Methods:
- Inoculation of silica and COAM-statolon in FLV-infected mice.
- Assessment of interferon production and antibody response.
- Cell transfer experiments using spleen cells, T cells, and thymocytes.
Main Results:
- Silica treatment blocked the leukemosuppressive effects of COAM-statolon.
- Mice treated with silica and COAM-statolon produced interferon but lacked cytotoxic antibodies.
- Transfer of T lymphocytes restored the humoral immune response and resulted in leukemosuppression.
Conclusions:
- T lymphocytes are crucial for the humoral immune response against FLV antigens.
- T lymphocytes play a direct or indirect role in FLV leukemosuppression.
- Silica interferes with T lymphocyte-mediated immune responses to FLV.
