CD4+ Foxp3+ Regulatory T cells in autoimmune orchitis: phenotypic and functional characterization.

Abstract

Problem: The phenotype and function of regulatory T (Treg) cells in rats with experimental autoimmune orchitis (EAO) was evaluated. Method of study: Distribution of Treg cells in draining lymph nodes from the testis (TLN) and from the site of immunization (ILN) was analysed by immunohistochemistry. The number, phenotype and proliferative response (5-bromo-2′-deoxyuridine incorporation) of Treg cells were evaluated by flow cytometry and Treg cell suppressive activity by in vitro experiments. TGF-β expression was evaluated by immunofluorescence. Results: Absolute numbers of Treg cells and BrdU+ Treg cells were increased in LN from experimental compared to normal and control rats. These cells displayed a CD45RC−, CD62L−, Helios+ phenotype. CD4+ CD25bright T cells from TLN of experimental rats were able to suppress T cell-proliferation more efficiently than those derived from normal and control rats. Cells isolated from TLN and ILN expressed TGF-β. Conclusion: Our results suggest that Treg cells with a memory/activated phenotype proliferate extensively in the inflamed testis and LN of rats with EAO exhibiting an enhanced suppressive capacity. TGF-β may be involved in their suppressive mechanism.