Figure 1
From: Role of PD-1 co-inhibitory pathway in HIV infection and potential therapeutic options
Regulation of CD8 + T cells after acute/chronic viral infection. Highly complex network of co-inhibitory and co-stimulatory signaling pathways regulate the outcome of virus-specific CD8 T cells. High amount of antigen drives the exhaustion of virus-specific CD8+ T cells during chronic viral infection that is evidenced by the expression of multiple immune-inhibitory receptors. (Note: Exhausted T cells with loss of function may not control chronic viral infection). However, during acute viral infection the antigen is cleared from the host and the virus-specific CD8 T cells are fully functional and produce cytokines and have proliferative potential, survival and cytotoxicity to control viral infection.