Human CD8+ T-cell differentiation in response to viruses

Most markers that define functional subsets of CD8+ T cells are regulated by activation, which complicates their use as differentiation markers.Although during acute infection overall similarities dominate between T cells specific for different viruses, their phenotypes seem to be distinct in the memory/latency stage.Infection with cytomegalovirus has a dominant influence on the circulating CD8+ T-cell pool, promoting the generation and maintenance of a population with stable cytolytic function.Specific co-stimulatory ligands (or cytokines) present during the initial priming or memory/latency stages might direct CD8+ T-cell differentiation and account for differences between T cells that react to different viruses.