Assessment of lymphoid development and transgene copy numbers in treated animals.

(A) Lymphoid development after stem cell gene therapy (8 weeks after BMT). Presented are absolute counts of PB lymphocytes (PBLs), mature B cells (B220⁺/IgM⁺), CD4⁺ T cells (total and CD62L⁺), and CD8⁺ T cells. Shown are the mean (±SD) values obtained from 6 wild-type mice (γc⁺), 9 untreated Δγc⁺-XSCID mice (XSCID), 4 mock-BMT mice (mock), 8 mγc-BMT mice (mγc), and 3 control-BMT mice (control). (B) Transgene copy numbers in mouse tissues. PCR products derived from the mγc-provirus (326 bp) and control β-globin sequences (401 bp) were separated on agarose gel and quantified as described in “Materials and methods.” Copy numbers estimated by interpolation with the reference standard are indicated. Sp; splenocytes, Thy; thymocytes. As expected, MNDmγc-bands are absent in BM samples obtained from untreated Δγc⁺-XSCID mice (XSCID, lane 2) and mock-BMT mice (mock, lane 3).