FIG 1.

Flow cytometric analyses of allelic exclusion, allelic inclusion, and isotypic competition. (A) Single-cell suspensions from the bone marrows of mice with the indicated genotypes were stained with anti-B220 and monoclonal antibodies against the IgM^a and IgM^b allotypes and then gated on the B220⁺ population. Representative plots are shown (n = 5). (B) Cells from the bone marrows of mice with the indicated genotypes were stained with anti-B220, anti-IgM, and anti-IgG3 and then gated on the B220⁺ population. Representative plots are shown (n = 4). (C) Schematic recapitulating the FACS data for A150/+ mice. IgM is produced only from the wild-type allele. From the mutant allele, only IgG3 is expressed.