Chronic Viral Infection Compromises the Quality of Circulating Mucosal-Associated Invariant T Cells and Follicular T Helper Cells via Expression of Inhibitory Receptors

• Background: Chronic viral infection results in impaired immune responses rendering viral persistence. Here, we compared the quality of T-cell responses among chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-infected individuals by examining the levels of expression of selected immune activation and exhaustion molecules on circulating MAIT cells and Tfh cells. Methods: Cytokines were measured using a commercial Bio-plex Pro Human Cytokine Grp I Panel 17-plex kit (BioRad, Hercules, CA, USA). Inflammation was assessed by measuring an array of plasma cytokines, and phenotypic alterations in CD4(+) T cells including circulating Tfh cells, CD8(+) T cells, and TCR iV alpha 7.2(+) MAIT cells in chronic HBV, HCV, and HIV-infected patients and healthy controls. The cells were characterized based on markers pertaining to immune activation (CD69, ICOS, and CD27) proliferation (Ki67), cytokine production (TNF-alpha, IFN-gamma) and exhaustion (PD-1). The cytokine levels and T cell phenotypes together with cell markers were correlated with surrogate markers of disease progression. Results: The activation marker CD69 was significantly increased in CD4(+hi) T cells, while CD8(+) MAIT cells producing IFN-gamma were significantly increased in chronic HBV, HCV and HIV infections. Six cell phenotypes, viz., TNF-alpha(+)CD4(+lo) T cells, CD69(+)CD8(+) T cells, CD69(+)CD4(+) MAIT cells, PD-1(+)CD4(+hi) T cells, PD-1(+)CD8(+) T cells, and Ki67(+)CD4(+) MAIT cells, were independently associated with decelerating the plasma viral load (PVL). TNF-alpha levels showed a positive correlation with increase in cytokine levels and decrease in PVL. Conclusion: Chronic viral infection negatively impacts the quality of peripheral MAIT cells and Tfh cells via differential expression of both activating and inhibitory receptors.

Ämnesord

NATURVETENSKAP  -- Biologi -- Immunologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Immunology (hsv//eng)

Nyckelord

HBV; HIV; MAIT cells; PD-1; T cell exhaustion

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