Figure 6.

Hematopoietic colonies after 13 days in culture. (A) Aliquot of wild-type BM cells before injection (input cells). (B and C) The low-density cell fraction was isolated from 0.5 ml of blood of lethally irradiated recipients 14 hr after injection of wild-type BM cells. After 13 days of culture, very few colonies grew from the blood of wild-type recipient mice treated with IgG (B) or VCAM-1 antibody (not shown; see Table 2). However, many large colonies (>3 mm) grew from the blood of (C) P/E−/− recipients treated with anti-VCAM-1 (arrow).