BM B-cell precursor depletion following GCV treatment of Col2.3Δ-TK transgenic mice precedes depletion of BM LSK cells and is not seen in the spleen. (A) Total LSK cells recovered from the BM (2 hind legs) of GCV-treated and control mice at day 21 and day 28 (means ± SD; n = 5). (B) Flow cytometric detection (left-hand panel) and total numbers (right-hand panel) of B220⁺CD19⁺ B lymphocytes in the spleens 28 days after treatment with vehicle or GCV (means ± SD, n = 5). (C-D) The absolute numbers of recovered BM B-lymphocyte subsets (C) (B220⁺CD19⁻ pre-pro-B, B220⁺CD19⁺ pro-B, B220⁺⁺CD19⁺ and B220⁺⁺CD19⁺⁺ pre-B, and immature B cells), as well as those of splenic mature B cells (D) at day 21 and day 28 after GCV treatment (means ± SD, n = 4).