Kinetics of CD8+ effector T cell responses and induced CD4+ regulatory T cell responses during Friend retrovirus infection.

Cytolytic CD8+ T cells are critical for the control of acute Friend virus (FV) infection yet they fail to completely eliminate the virus during chronic infection because they are functionally impaired by regulatory T cells (Treg). We performed a kinetic analysis of T cell responses during FV infection to determine when dysfunction of CD8+ T cells and suppressive activity of CD4+ regulatory T cells develops. At 1 week post infection, virus-specific CD8+ T cells with effector phenotype and cytolytic potential expanded.