Combined pretreatment with KGF and androgen blockade maximally restores numbers of totalTECsand mTEC subsets by day 26afterBMT. (A-F) Lethally irradiated B6 recipients of allogeneic (BALB/c) bone marrow were left untreated (BMT Control) or pretreated with KGF, leuprolide acetate, or KGF + leuprolide acetate and analyzed for absolute numbers of TEC and TEC subsets at day 26 after BMT. Single-cell suspensions were prepared from enzymatic digests of individual thymi and used to determine total thymic epithelial cells (TEC; CD45⁻MHC-II⁺) (A), cortical TEC (cTEC; CD45⁻MHC-II⁺Ly51⁺) (B), medullary TEC (mTEC; CD45⁻MHC-II⁺Ly51⁻) (C), UEA-1⁺ mTEC^lo (CD45⁻MHC-II^lowLy51⁻ UEA-1⁺) (D), UEA-1⁺ mTEC^hi (CD45⁻MHC-II^highLy51⁻ UEA-1⁺) (E), AIRE⁺ mTEC^hi (CD45⁻MHC-II^highLy51⁻ AIRE⁺) (F). (G-J) Total TECs and individual TEC subsets were assessed for proliferation by continuous administration of BrdU in the drinking water (0.8 mg/mL) between day 10 and 14 after BMT at which point Total TECs (G), cTEC (H), mTEC^lo (I), and mTEC^hi subsets (J) were analyzed for BrdU incorporation. Data shown are the mean numbers of TEC (± SEM) or mean percentages of BrdU⁺ TEC (± SEM) and are representative of one experiment of 4 mice per group. *P < .05 compared with BMT control mice; #P < .05 compared with KGF- or leuprolide acetate-treated BMT recipients.