Normalization of T-cell activation markers after gene therapy of γ_c-deficient mice. (A) CD4⁺ T cells from γ_c-deficient mice transduced with human γ_c exhibited normalization of CD62L expression. (B) CD4⁺ T cells from γ_c-transduced mice exhibited normalization of anti-CD3–induced IL-2R expression, whereas cells from mock-transduced mice did not. The specificity of this finding was confirmed by the use of an isotype-matched antibody (data not shown). Shown are data for wild-type and γ_c-deficient mice or γ_c-deficient mice that receive γ_c-deficient bone marrow mock-transduced or transduced with human γ_c. Shown are representative mice from 1 of 5 experiments.