Fig. 1.
Representative flow cytometry of bone marrow showing separation of B lineage subsets by cell-surface antigen expression in 4-week-old Eμ-ret (Tg+) and transgene-negative (Tg−) mice. (A) CD45R+ B lineage cells are resolved into less differentiated (CD43+) and more differentiated subsets (CD43−). The CD43+subset, which is markedly expanded in the Eμ-ret mice, comprises the three pro–B-cell fractions (Fr A through C) and the early pre–B-cell fraction (Fr C′). (B) The CD45R+CD43+subset is further resolved into Fr A through C′ based on BP-1 and CD24 expression. There is a selective expansion of the BP-1+CD24+ late pro–B-cell fraction C in the Eμ-ret mice.