Hypomorphic VCAM-1 D4D mice.

(A) D4D mice have an increased number of circulating CFU-Cs and CFU-Ss compared to controls (P = <.05) and when used as recipients in homing assays, display decreased lodgment to BM compared to controls, and increased numbers of circulating CFU-Cs at 3 hours after injection (upper right panel). The homing is virtually abolished when these mice were injected with anti–VCAM-1 (MK/2; 2 mg/kg ×2, 12 hours apart) and given anti-CD11a–treated BM cells (striped column). (B) Constitutive expression of VCAM-1 in wild-type spleen and BM (total RNA 40 μg) is approximately 20-fold greater than that observed in the spleen and BM of D4D littermates.