B-cell reduction induced by TERT CTLs is transient. (A) BM B-cell subsets after ACT treatment. C57BL/6 mice (n = 6/group) received ACT, and BM was collected 5 days later. B220 staining identifies BM B cells (top). Wilcoxon rank sum test: β-gal vs mTERT, P = .005. B-cell subpopulations were then characterized (bottom) as follows: pro-B: B220⁺/CD43⁺/IgM⁻; pre-B: B220⁺/CD43⁻/IgM⁻; naive B220⁺/CD43⁻/IgM⁺. Wilcoxon rank sum test: pro-B mTERT vs pro-B β-gal, P = .005. (B) Spleen B-cell subsets after ACT treatment. C57BL/6 mice (n = 6/group) received ACT and spleens were collected 5 days later. B220 staining shows a profound B-cell depletion in mice treated with TERT ACT. Wilcoxon rank sum test: β-gal vs mTERT, P = .002. Staining for expression of CD43 and surface IgM allowed characterization of B-cell subpopulations (pro-B: B220⁺/CD43*/IgM⁻; pre-B: B220⁺/CD43⁻/IgM⁻; naive: B220⁺/CD43⁻/IgM⁺). Wilcoxon rank sum test: pro-B mTERT vs pro-B β-gal, P = .005. (C) B220 staining of TRAMP mice spleens by IHC. Spleens were collected at 24 weeks (mTERT n = 18 and β-gal-n = 16) or at 40 weeks of age (mTERT n = 6). Samples were scored for the B220 positivity with a scale from 1 to 5. Wilcoxon rank sum test: mTERT at 24 weeks vs β-gal at 24 weeks, P = .007; mTERT at 40 weeks vs β-gal at 24 weeks, P = .8; mTERT at 40 weeks vs mTERT at 24 weeks, P = .05.