[ Schistosoma japonicum heat shock protein 60 enhances regulatory T cell immunosuppressive function by promoting the expressions of IL-10 and TGF-β].

OBJECTIVE: To explore the possible mechanisms by which Schistosoma japonicum heat shock protein 60 (SjH-SP60) enhances CD4+ CD25+ regulatory T cell (Treg) immunosuppressive function.

METHODS: An in vitro method was used to investigate the effect of SjHSP60 on Treg immunosuppressive activity. Co-cultures in transwells and in vitro suppression assay were performed to investigate how SjHSP60 enhanced the immunosuppressive function of Tregs. Intracellular cytokine staining combined with flow cytometry was used to detect Treg-expressing IL-10 and TGF-β, and flow cytometry was also used to analyze the expressions of Foxp3 and CTLA-4 in Tregs.

RESULTS: SjHSP60 enhanced the immunosuppressive function of Tregs. Soluble cytokines IL-10 and TGF-β mediated inhibitory activity of SjHSP60-triggered Tregs. SjHSP60 induced significant increases in both IL-10 and TGF-β expressions of Tregs. Further investigation showed significant increased Foxp3 and CTLA-4 in SjHSP60-trggered Tregs.

CONCLUSIONS: SjHSP60 enhances Treg immunosuppressive function by promoting the expressions of IL-10 and TGF-β, possibly due to SjHSP60-mediated induction of Foxp3 and CTLA-4 in Tregs.