Review Article

Shaping Successful and Unsuccessful CD8 T Cell Responses Following Infection

Figure 2

Successful activation of CD8 T cells requires three signals by APCs and CD4 T cell help. CD8 T cells engage cognate peptide-MHC complexes presented on APCs with their TCR (1). The APC also provides costimulation to the T cell via expression of CD80/CD86 molecules, which bind to CD28 on the T cell (2). Finally, the APC produces IL-12 after activation with inflammatory mediators or in response to CD40L interactions with CD4 T cells, and IL-12 provides signal 3 to the responding CD8 T cell. (3) CD4 T cells also produce cytokines that provide growth and differentiation signals to responding CD8 T cells.
159152.fig.002