Figure 4.

Comparative analysis of in vivo and in vitro B cell development. Bone marrow B cells isolated from a mouse carrying hemizygous 3-83Hi and homozygous 3-83ki genes on a mixed (BALB/c × C57BL/6 × 129) H-2^d background were analyzed ex vivo (freshly isolated) or after culture on the ST2 stroma cell line in the presence or absence of IL-7. Flow cytometric analysis of 3-83 (54.1) and IgM staining of B220^low (immature) gated cells is shown. Numbers refer to frequency of 3-83Ig⁺ cells in the total sIgM⁺ (B220^low) cell population.