• To appreciate the critical role that IL-2 plays in T cell activation • To understand what regulatory T cells (T regs) are, how they are activated, what their
 immunological role is and how they carry out their regulatory functions • To be able to recall the name and function of the key molecules involved in: - the activation and effector function of Th1 cells - the activation and effector function of Th2 cells, as well as - the activation and effector function of Th17 cells
 Today we will focus on the clonal expansion/proliferate of T cells after they become activated (from naïve T cell  gets presented with antigens with MHC molecules on the surface of the cell). With co-stimulation, the naïve T cell will transform to become an activated T cell. There are 2 main types of T cells – – Effector T cells: To be able to eliminate the pathogen that you’ve encountered – Memory T cells: To be able to hang around for an extended period of time to be long lived, so that if you ever
 come into contact with the same pathogen, you will be protected There are specific T helper cells which perform specific functions to eliminate specific antigens.
 Interleukin-2 (IL-2) is the most important cytokine in turning on genes, which induces T cell proliferation.
 We are going to be focusing on 4 types of T cells – Regulatory T cells (T regs), T Helper 1 (Th1), T helper 2 (Th2) and
 T helper 17 (Th17) cells