Figure 1.

A heritable B cell deficiency. (a) Frequencies of CD19⁺ and Thy1.2⁺ blood lymphocytes in the emptyhive pedigree. Percentages (b, c, e) and numbers (d) of B cell subsets in bone marrow (b), spleen (c) and peritoneal cavity (e). Hardy fractions in bone marrow (A-F) were gated as follows: A (B220⁺CD43⁺BP-1⁻CD24⁻); B (B220⁺CD43⁺BP-1⁻CD24⁺); C (B220⁺CD43⁺BP-1⁺CD24⁺); D (B220⁺CD43⁻IgM⁻IgD⁻); E (B220⁺CD43⁻IgM⁻IgD⁺); F (B220⁺CD43⁻IgM⁺IgD⁺). The C' fraction (B220⁺CD43⁺BP⁻1⁺CD24^hi) was not resolved. Fractions A and B-D may also be gated as CD19⁻ and CD19⁺ populations among B220⁺IgM⁻cells, respectively (b). IgM⁺ splenocytes were divided into the following subsets: T1 (CD93⁺CD23⁻); T2 (CD93⁺CD23⁺IgM^int); T3 (CD93⁺CD23⁺IgM^hi); MZ (CD93⁻CD23⁻IgM^hiCD21^hi); Fo (CD93⁻CD23⁺). Peritoneal lymphocytes were divided into B-2 (CD19⁺B220^hi), B-1 (CD19⁺B220^lo−int), B-1a (CD5⁺CD43⁺) and B-1b (CD5⁻CD43⁻) subsets. (f) IgM allotype expression on CD19⁺ blood lymphocytes from wild-type and emptyhive mice on a (C57BL/6 × BALB/c)F2 (IgM^a/b) background. Data are representative of three (a to e), or one (f) independent experiments using three mice per genotype. Each symbol represents an individual mouse.