Requirement for splenic CD4(+) T cells in the immune privilege of the anterior chamber of the eye

Injection of antigen into the anterior chamber of the eye induces suppressi on of antigen-specific DTH, called anterior chamber-associated immune devia tion (ACAID). It has been shown that the spleen is required for the inducti on of ACAID and detecting the ACAID-inducing signal from the eye. To examin e the in vivo role of spleen cells, fractions of spleen cells were adoptive ly transferred into splenectomized mice. The present study showed that DTH was not suppressed in splenectomized mice, but was inhibited in splenectomi zed mice transferred with a primed CD4(+) T cell-containing fraction of spl een cells. This indicates that the splenic CD4(+) T cells comprise the regu latory T cells for the DTH response. When we examined the cytokine profile of the infiltrating T cells in the eye of primed mice by reverse transcript ase-polymerase chain reaction (RT-PCR), we found that they expressed IL-4, IL-10 mRNA (Th2 type), but not IL-2 and interferon-gamma (IFN-gamma) mRNA ( Th1 type). By contrast, T cells which can elicit normal DTH response expres sed IL-2 and IFN-gamma mRNA. These results suggest that splenic CD4(+) T ce lls comprising the regulatory phenotype are required for the induction of A CAID, and that a DTH response to the antigen may be prevented by Th2-domina nt CD4(+) T cells.