MGI:97553T-cell specific knock-out results in more robust development of effector functions in stimulated nave CD8+ T cells. Mice homozygous for a conditional allele activated in T cells exhibit enlarged peripheral lymphoid organs, splenomegaly, lymphoproliferation of CD4/CD8 T-cells, and super high IFN, IL-17A, IL-4, and IL-5 levels in serum with reduced injected tumor cell growth.