Transplantation of normal hematopoietic cells corrects the WAS-null phenotype.

(A) Survival of C57/BL6J WAS-null mice after bone marrow transplantation. Transplant procedures were as described in “Study design.” N3 recipients included 3 “F1” N3 mice (progeny of N3×N3 matings). (B) Mean hematologic values in C57/BL6J WAS-null males (“KO”), WT littermates, and WAS−/C57/BL6J males 12 to 14 weeks after transplantation with WT (Ly5.1) marrow. The difference between WT and KO lymphocyte counts was significant atP = .03; all other differences between KO and either WT or transplantation groups were significant to P < .01. Error bars = 1 standard error. (C) Proliferation of primary splenic T-cell cultures after stimulation with immobilized anti-CD3 antibody or soluble human IL-2. Each assay was performed in triplicate. Error bars = 1 standard error. (D) Representative flow cytometry data from recipient peripheral blood lymphocytes at 14 weeks after transplantation, showing complete B-cell (B220⁺) Ly5.1 donor engraftment and a small amount (2.4% in this case) of residual Ly5.2 host-derived T cells (Thy 1.2⁺).