Immunosuppression by CD4+ regulatory T cells induced by chronic retroviral infection
AUTOR(ES)
Iwashiro, Michihiro
FONTE
The National Academy of Sciences
RESUMO
Normal levels of CD4+ regulatory T cells are critical for the maintenance of immunological homeostasis and the prevention of autoimmune diseases. However, we now show that the expansion of CD4+ regulatory T cells in response to a chronic viral infection can lead to immunosuppression. Mice persistently infected with Friend retrovirus develop approximately twice the normal percentage of splenic CD4+ regulatory T cells and lose their ability to reject certain tumor transplants. The role of CD4+ regulatory T cells was demonstrated by the transmission of immunosuppression to uninfected mice by adoptive transfers of CD4+ T cells. CD4+ T cells from chronically infected mice were also immunosuppressive in vitro, inhibiting the generation of cytolytic T lymphocytes in mixed lymphocyte cultures. Inhibition occurred at the level of blast-cell formation through a mechanism or mechanisms involving transforming growth factor-β and the cell surface molecule CTLA-4 (CD152). These results suggest a possible explanation for HIV- and human T cell leukemia virus-I-induced immunosuppression in the absence of T cell depletion.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=55402Documentos Relacionados
- CD4+ T cells are required to sustain CD8+ cytotoxic T-cell responses during chronic viral infection.
- Regulatory function of in vivo anergized CD4+ T cells
- Protective cellular retroviral immunity requires both CD4+ and CD8+ immune T cells.
- Soluble HLA-G protein secreted by allo-specific CD4+ T cells suppresses the allo-proliferative response: A CD4+ T cell regulatory mechanism
- Apoptotic depletion of CD4+ T cells in idiopathic CD4+ T lymphocytopenia.