B-cell developmental defects and autoimmune disease are not linked to the hematopoietic changes observed in Lyn^-/- mice. (A) Lyn^+/+, Lyn^-/-, Lyn^-/-;μMT/μMT, and μMT/μMT control mice were assessed for total immunoglobulin levels by ELISA, or (B) antinuclear antibody titers using DNA and nuclear antigen-coated ELISA plates incubated with a 1:500 dilution of sera from mice of the indicated genotypes. Relative optical densities are shown. (C) Total numbers of CD71⁺Ter119⁺ cells were enumerated following FACS analysis of spleen cell preparations from mice of the indicated genotypes. (D) Splenic CFU-e's and BFU-e's in mice of the indicated genotypes. Data in panels C-D are means (± SD) for 2 mice per genotype. Mean spleen weights were Lyn^+/+, 0.11 ± 0.01 g; Lyn^-/-, 0.31 ± 0.08 g; and Lyn^-/- μMT, 0.14 ± 0.05 g. (E) Splenic myeloid progenitor numbers responsive to the indicated cytokines in mice of the indicated genotypes. Data represent the mean (± SEM) for 2 mice per genotype per experiment in 2 separate experiments.