HCV‐specific CD27⁻ CD28⁻ memory T cells are depleted in hepatitis C virus and <i>Schistosoma mansoni</i> co‐infection

Abstract

Factors that influence the generation and maintenance of memory CD8+ T cells are not fully understood. The homeostasis of memory T cells is highly dynamic and tightly regulated by various stimuli, including cytokines and antigen-major histocompatibility complex ligands. We characterized the hepatitis C virus (HCV)-specific CD8+ T-cell responses in a cohort of HCV-infected individuals with or without Schistosoma mansoni co-infection from Egypt. We observed a significantly decreased CD27- CD28- (late differentiated) memory T-cell population in the HCV co-infected individuals compared to those with HCV infection alone. In contrast, there was no significant difference in the CD27+ CD28+ (early differentiated) memory T cells between the two groups. Analysis of human cytomegalovirus-specific CD8+ T-cell responses in the same individuals failed to reveal a similar pattern of altered memory T-cell differentiation. Thus, S. mansoni co-infection targets a specific subset of memory CD8+ T cells in HCV infection.