Parasite immunology 2016 8 23() doi 10.1111/pim.12358
Opisthorchis viverrini, causes public health problems in Southeast Asia. Recently, TGF-β and IL-10 have been reported to increase in O. viverrini infected hamsters but the sources of these cytokines are still unknown. In this study, the CD4(+) T cells in infected hamsters were investigated. It was demonstrated that IL-4(+) CD4(+) T cells were significantly increased in hamster spleens and mesenteric lymph nodes (MLNs) during chronic infection. Interestingly, IL-10(+) CD4(+) T cells were also discovered at a significant level while Treg (T regulatory)-like TGF-β(+) CD4(+) T cells were in MLNs of infected hamsters. Moreover, the CD4(+) CD25(+) Foxp3(+) Treg cell response was significantly found both in spleens and MLNs in infected hamsters. The findings were then confirmed by development of T cell clones against crude somatic antigens (CSAg) in immunized BALB/c mice. Five clones named TCC21, TCC23, TCC35, TCC41 and TCC108 were established. The TCC21 was found to be the TGF-β(+) CD4(+) while TCC35, TCC41 and TCC108 were IL-4(+) CD4(+) and TCC23 was IFN-γ(+) CD4(+) . This TGF-β(+) CD4(+) T clone showed an inhibitory function in vitro in mononuclear cell proliferation via TGF-β mediated mechanisms. This study indicated that O. viverrini infected hamsters could induce TGF-β(+) CD4(+) Treg-like cells. The CSAg specific Tregs secreted high TGF-β, and limited immune cell proliferation. This article is protected by copyright. All rights reserved.