High antigen density and IL-2 are required for generation of CD4 effectors secreting Th1 rather than Th0 cytokines.
Rogers PR, Huston G, Swain SL. High antigen density and IL-2 are required for generation of CD4 effectors secreting Th1 rather than Th0 cytokines. J Immunol. 1998 Oct 15; 161(8):3844-52.