Homing of CD34⁺ cells is facilitated by the major integrins VLA-4, VLA-5, and LFA-1 and is PTX insensitive.

(A) Enriched CB CD34⁺ cells (0.5 × 10⁶cells/mouse) were incubated with antibodies specific for the major integrins prior to transplantation into NOD/SCID/B2m^null mice. Data shown represent mean ± SE from 5 experiments, n = 22 mice,P < .05. (B) CD34⁺-enriched cells were incubated with PTX (100 ng/mL, 60 minutes, 37°C) and assayed for migration toward SDF-1 (Bi, control cells were not treated with PTX), or SDF-1–mediated adhesion to fibronectin (FN) (Bii, control = adhesion to FN in the absence of SDF-1), or homing levels in transplanted NOD/SCID mice (C, 1 × 10⁶ cells/mouse). CD34⁺ cells were treated with PTX alone or followed by incubation with anti CXCR4 mAb; control cells were not treated. Data represent the number of human cells per 10⁶ total acquired cells; a representative experiment from 3 performed is shown. Results from all experiments gave similar results (P < .05; n = 9 mice).