CD4+ Foxp3+ Regulatory T Cells in Autoimmune Orchitis: Phenotypic and Functional Characterization

ProblemThe phenotype and function of regulatory T (Treg) cells in rats with experimental autoimmune orchitis (EAO) was evaluated. Method of studyDistribution 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- expression was evaluated by immunofluorescence. ResultsAbsolute 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(+)CD25(bright) 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-. ConclusionOur 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- may be involved in their suppressive mechanism.