title: Induction of regulatory T cells by Opisthorchis viverrini.
abstract: Opisthorchis viverrini causes public health problems in South-East 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.
authors.affiliation: Department of Microbiology, Khon Kaen University, Khon Kaen, Thailand.|Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: C
authors.initials: C
authors.lastname: Kaewraemruaen
authors.affiliation: Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand.|Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: R W
authors.initials: RW
authors.lastname: Sermswan
authors.affiliation: Department of Microbiology, Khon Kaen University, Khon Kaen, Thailand. sura_wng@kku.ac.th.|Melioidosis Research Center, Khon Kaen University, Khon Kaen, Thailand. sura_wng@kku.ac.th.
authors.forename: S
authors.initials: S
authors.lastname: Wongratanacheewin
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D006224:Cricetinae; D016207:Cytokines / Q000276:immunology; D051858:Forkhead Transcription Factors; D015847:Interleukin-4 / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009889:Opisthorchiasis / Q000276:immunology* / Q000469:parasitology; D009891:Opisthorchis / Q000502:physiology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology
chemical_list: D016207:Cytokines; D051858:Forkhead Transcription Factors; D015847:Interleukin-4
keywords:  Opisthorchis viverrini ; BALB/c mice; hamster; regulatory T cells