C Mechanisms of th cell-mediated activation of b cells Th cells that recognize Ag presented by b cells activated B cell by expressing CD4oL and by secreting cytokines(IL-2, IFN-Y, IL-4, IL-5, IL-6, IL-13, etc.)c. Mechanisms of Th cell-mediated activation of B cells  Th cells that recognize Ag presented by B cells activated B cell by expressing CD40L and by secreting cytokines (IL-2, IFN-, IL-4, IL-5, IL-6, IL-13, etc.)