Foxp3+CD4+CD25+ T cells control virus-specific memory T cells in chimpanzees that recovered from hepatitis C.
Hepatitis C virus (HCV) poses a global health problem because it readily establishes persistent infection and a vaccine is not available. CD4(+)CD25(+) T cells have been implicated in HCV persistence because their frequency is increased in the blood of HCV-infected patients and their in vitro depletion results in increased IFN-gamma production by HCV-specific T cells. Studying a well-characterized cohort of 16 chimpanzees, the sole animal model for HCV infection, we here demonstrate that the frequency of Foxp3(+)CD4(+)CD25(+) regulatory T cells (T(Regs)) and the extent of suppression was as high in spontaneously HCV-recovered chimpanzees as in persistently HCV-infected chimpanzees. Foxp3(+)CD4(+)CD25(+) T(Regs) suppressed IFN-gamma production, expansion, and activation-induced cell death of HCV-specific T cells after recovery from HCV infection and in persistent HCV infection. Thus, T(Reg) cells control HCV-specific T cells not only in persistent infection but also after recovery, where they may regulate memory T-cell responses by controlling their activation and preventing apoptosis. However, Foxp3(+)CD4(+)CD25(+) T(Reg) cells of both HCV-recovered and HCV-infected chimpanzees differed from Foxp3(+)CD4(+)CD25(+)T(Reg) cells of HCV-naive chimpanzees in increased IL-2 responsiveness and lower T-cell receptor excision circle content, implying a history of in vivo proliferation. This result suggests that HCV infection alters the population of Foxp3(+)CD4(+)CD25(+) T(Reg) cells.
Immunology Section, Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Tobias
T
Manigold
Eui-Cheol
EC
Shin
Eishiro
E
Mizukoshi
Kathleen
K
Mihalik
Krishna K
KK
Murthy
Charles M
CM
Rice
Ciriaco A
CA
Piccirillo
Barbara
B
Rehermann
D000818:Animals; D017209:Apoptosis; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000502:physiology*; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000276:immunology*; D007156:Immunologic Memory; D007371:Interferon-gamma; D008213:Lymphocyte Activation; D002679:Pan troglodytes; D037182:T-Cell Antigen Receptor Specificity; D013601:T-Lymphocytes / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000502:physiology*
D051858:Forkhead Transcription Factors; D007371:Interferon-gamma