Figure 1.

Representative flow cytometric analyses of splenic B cells from PTP-deficient mice. Expression of IgM and IgD was evaluated on splenic cells from age-matched 4-wk-old mice: CD45⁺/SHP-1⁺ (C57B1/6 wild type); CD45⁻/ SHP-1⁺ (C57B1/6 CD45 exon 6^−/−; originally derived by K. Kishihara; reference 8; eighth backcross generation), CD45⁺/SHP-1⁻ (C57B1/6 me^v/me^v); CD45⁻/SHP-1⁻ mice (derived by mating C57B1/6 CD45 exon 6^−/− [eighth backcross generation] with C57B1/6 me^v/+ mice). The percentages of cells within the boxed regions correspond to the following pattern: I, percent δ⁺μ⁻ in the lymphoid gate; II, percent δ^hiμ^lo of III; III, percent δ⁺μ⁺ in the lymphoid gate; IV, percent δ⁻μ⁺ in the lymphoid gate. The lymphoid gate was set by standard procedures relying on the forward and side scatter properties of the splenic cells. The absolute numbers of various subsets of cells found in the spleens of the same mice (× 10⁶) for CD45⁺/SHP-1⁺, CD45⁻/SHP-1⁺, CD45⁺/SHP-1⁻, CD45⁻/SHP-1⁻), total splenic cells were 79, 120, 140, and 56, respectively. Lymphoid gate: 68, 95, 95, 41; μ⁺δ⁺: 33, 76, 7.2, 9.1; μ^loδ^lo: 15, 5.2, 3.6, 4.4; μ⁺δ⁻, 1.6, 3.4, 8.2, 1.1; μ⁻δ⁺: 0.5, 0.06, 1.6, 0.05; μ⁺CD5⁺: 5.7 (representing 16% of μ⁺ cells), 4.5 (6%), 11 (71%), 3.6 (37%). Data are representative of four independent experiments carried out as described in Materials and Methods.