The role of E proteins in the CD8+ T cell immune response

CD8 + T cells are essential cells of the immune system because they mediate control of infection by intracellular pathogens such as bacteria, viruses and protozoan parasites. Naïve CD8 + T cells, upon encounter with antigen, differentiate into effector T cells, which rapidly elicit an immune response to eliminate infected cells. Upon removal of the pathogen, a subset of effector cells will further differentiate into memory T cells, remaining to respond to subsequent infection. E proteins and their inhibitors, the Id proteins, have been shown to be crucially important in regulating the development of T cells in the thymus. We have also recently shown that Id2 protein, an inhibitor of E protein DNA binding, is essential for CD8 + T cell responses. We speculate that E proteins, and their transcriptional targets, regulate the activation and formation of CD8 + effector T cells during an immune response. Using E2A‐GFP reporter mice and EMSA studies, we show that E proteins are up‐regulated and bound to DNA during the early stages of the T cell immune response. Using E protein conditional knock‐out mice, we are currently studying the role of E proteins in the in vivo CD8 + T cell response.