T cell activation

Patent Granted Activation of CD4+ T cells occurs through the simultaneous engagement of the T cell receptor and a costimulatory molecule (like CD28, or ICOS) on the T cell by the major histocompatibility complex (MHCII) peptide and costimulatory molecules on the APC. Both are required for production of an effective immune response; in the absence of costimulation, T-cell receptor signalling alone results in anergy. The signalling pathways downstream from costimulatory molecules usually engages the PI3K pathway generating PIP3 at the plasma membrane and recruiting PH domain containing signaling molecules like PDK1 that are essential for the activation of PKCtheta, and eventual IL-2 production.