Thymic output in FV vector–treated animals with and without G-CSF/AMD3100 mobilization. (A) Fraction of CD45RA⁺ cells within the CD3⁺ population in peripheral blood of nonmobilized animals R2258 and R2260. (B) Fraction of CD3⁺CD45RA⁺ cells in animals H864 and H867 treated with G-CSF/AMD3100 mobilization and vector PGK.γC.FV. (C) TREC levels in peripheral blood of the same animals shown in panel A. (D) TREC levels measured in the same animals shown in panel B. In panels A and B, dashed line shows average percentage of CD45RA⁺ cells from normal dog; in panels C and D, dashed line shows TREC levels from a normal littermate control.