In mTOR overexpressing mice treated with rapamycin for 3 hr after CLP, we found that rapamycin inhibition of mTOR did attenuate CTLA4 accumulation and rescue CD4+ T cell deficiency and dysfunction, and the autophagy inhibitor bafilomycin A1 can reverse the above mitigating effects. Here, CTLA4 is linked to congenital T-cell immunodeficiency.