English: 1. After the naive T cell (N) encounters an antigen it becomes activated and begins to proliferate (divide) into many clones or daughter cells. 2. Some of the T cell clones will differentiate into effector T cells (E) that will perform the function of that cell (e.g. produce cytokines in the case of helper T cells or invoke cell killing in the case of cytotoxic T cells). 3. Some of the cells will form memory T cells (M) that will survive in an inactive state in the host for a long period of time until they re-encounter the same antigen and reactivate.