1. Hepatitis C Virus (HCV)-Specific CD8+ Cells Produce Transforming Growth Factor ß That Can Suppress HCV-Specific T-Cell Responses.
- Author
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Alatrakchi, Nadia, Graham, Camilla S., Van der Vliet, Hans J. J., Sherman, Kenneth E., Exley, Mark A., and Koziel, Margaret James
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HEPATITIS C virus , *T cells , *HIV infections , *INTERFERONS , *VIRAL antibodies , *TRANSFORMING growth factors-beta , *INTERLEUKIN-10 , *CYTOKINES - Abstract
Hepatitis C virus (HCV)-specific T-cell responses are rarely detected in peripheral blood, especially in the presence of human immunodeficiency virus (HIV) coinfection. Based on recent evidence that T-regulatory cells may be increased in chronic HCV, we hypothesized that functional blockade of regulatory cells could raise HCV-specific responses and might be differentially regulated in the setting of HIV coinfection. Three groups of subjects were studied: HCV monoinfected, HCV-HIV coinfected, and healthy controls. Frequencies of peripheral T cells specific for peptides derived from HCV core, HIV type 1 p24, and recall antigens were analyzed by gamma interferon (IFN-γ) enzyme-linked immunospot assay. HCV-specific T-cell responses were very weak in groups with HCV and HCV-HIV infections. Addition of blocking antibodies against transforming growth factor β1 (TGF-β1), -2, and -3 and interleukin-10 specifically increased the HCV-specific T-cell responses in both infected groups; however, this increase was attenuated in the group with HCV-HIV coinfection compared to HCV infection alone. No increase in recall antigen- or HIV-specific responses was observed. Flow cytometric sorter analysis demonstrated that regulatory-associated cytokines were produced by HCV-specific CD3+CD8+CD25- cells. Enhancement of the IFN-γ effect was observed for both CD4 and CD8 T cells and was mediated primarily by TGF-β1, -2, and -3 neutralization. In conclusion, blockade of TGF-β secretion could enhance peripheral HCV-specific T-cell responses even in the presence of HIV coinfection. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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