Splenic CD8 + T cells secrete TGF-β1 to exert suppression in mice with anterior chamber-associated immune deviation

Background CD8 + regulatory T cells (Treg) have been considered to be involved in a model of ocular-induced tolerance, known as anterior chamber-associated immune deviation (ACAID). The mechanisms of suppression by CD8 + T cells in ACAID remain only poorly understood. TGF-β1 is considered as an inhibitory cytokine for immunosuppression in some models. The production of TGF-β1 by CD8 + T cells in ACAID, and whether CD8 + T cells exert suppression through TGF-β1, is unknown. Methods The suppressive effect of CD8 + T cells in ACAID mice was determined by a local adoptive transfer (LAT) assay. The production of TGF-β1 by CD8 + T cells was measured by enzyme-linked immunosorbent assay (ELISA). Anti-TGF-β1 antibodies were used in the LAT assay to test if they could block the inhibitory effect of CD8 + T cells. Results CD8 + T cells from ACAID mice were shown to block the delayed-type hypersensitivity (DTH) response in an antigen-specific manner in a LAT assay. These CD8 + T cells secreted TGF-β1, and their suppression could partially be blocked by anti-TGF-β1 antibodies. Conclusions Our study confirms that CD8 + T cells from ACAID mice possess inhibitory properties. This population exerts part of its suppressive function via the production of TGF-β1.