| Purpose: To study the expression and functional characteristics of programmed death-1 (PD-1) and its ligands in the spleen of mice undergoing anterior chamber associated immune deviation (ACAID).
Methods: ACAID was induced in BALB/c mice by intracameral injection of ovalbumin (OVA). The expression of PD-1 and its ligands in the spleen from ACAID mice were determined by quantitative real-time PCR, Western blotting, and flow cytometry. In vitro proliferation assays, enzyme-linked immunosorbent assays and adoptive transfer assays were used to investigate the functional characteristics of splenic CD4+PD-1+ T cells of ACAID mice.
Results: Both mRNA and protein of PD-1, PD-L1 and PD-L2 were markedly up-regulated in the spleen of ACAID mice as compared to controls. CD4+PD-1+ T cells from ACAID mice produced a large amount of IL-10 and exhibited an in vitro antigen-specific suppressive activity. CD4+PD-1+ T cells from ACAID mice were able to significantly inhibit the antigen-specific delayed-type hypersensitivity response when adoptively transferred to naïve mice.
Conclusions: CD4+PD-1+ T cells from ACAID mice, as regulatory cells, are involved in the induction of antigen-specific suppression in association with enhanced expression of IL-10. CD4+PD-1+ T cells in the murine spleen may represent a substantial population of regulatory T cells possibly responsible for the induction of ACAID after intracameral injection of antigen.
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