OBJECTIVESProgrammed death-1 (PD-1) up-regulation impairs virus-specific CD8+ T-cell responses during chronic viral infection. Whether PD-1 expression influences the virus-specific CD8+ T cells in humans with acute viral infection remains largely undefined. This study aims to characterize the PD-1 expression during acute hepatitis B (AHB), and further addresses the association between the PD-1 dynamics and memory T-cell formation during acute HBV infection.

METHODSPeripheral HBV-specific CD8+ T cells from 11 HLA-A2-positive AHB patients were longitudinally quantitatively analyzed, and PD-1, memory markers CCR7, CD45RA and CD127 and activation marker CD38 on HBV-specific CD8+ T cells were measured using flow cytometric assay. Serum ALT, HBsAg, HBsAb and HBV-DNA levels were evaluated for each subject.

RESULTSAll 11 AHB patients examined had multiple pentamer-positive CD8+ T-cell responses in their early phase of HBV infection. Specifically, their PD-1 on pentamer-positive CD8+ T-cells was significantly up-regulated at the onset of their disease. Following their disease resolution, the dynamic decrease in PD-1 expression was found to correlate with the phenotypic development of memory CD8+ T cells, indicated by the increases in CCR7, CD45RA and CD127 and decrease in CD38.

CONCLUSIONPD-1-mediated negative signaling may be closely associated with memory T-cell formation during acute self-limited hepatitis B.