Fig. 1.
B-cell development in the thymus is blocked at the pro–B-cell stage.
(A) Phenotype of CD45R+CD43+ pro–B cells harvested directly from the bone marrow (BM) or thymus (THY) of BALB/c mice. The frequency of cells in fractions A, B, C, and C′ stages of development was assessed by analysis of Ly51 (BP-1) and CD24 expression on the gated CD45R+CD43+ cells. (B) Cell cycle status of pro–B cells in the BM and thymus. Data in the figures are representative of 3 experiments.