Virus-Specific CD8+ T Cells Upregulate Programmed Death-1 Expression during Acute Friend Retrovirus Infection but Are Highly Cytotoxic and Control Virus Replication (original) (raw)

CD8 + T cells are crucial for the control of virus replication during infections, and their functionality can be influenced by the expression of inhibitory receptors like programmed death-1 (PD-1). This study examines the expression of PD-1 on CD8 + T cells during acute Friend retrovirus infection, revealing that activated CD8 + T cells predominantly upregulate PD-1, forming two subsets: PD-1 hi and PD-1 lo. The PD-1 lo subset is associated with higher production of antiviral cytokines, while PD-1 hi cells exhibit strong cytotoxic characteristics. Importantly, enhanced PD-1 expression does not signify T cell exhaustion in the context of acute infection, as both subsets play critical roles in controlling virus replication.