Aggregation of CD34⁺ hematopoietic progenitors.

Aggregation induced by γIP-10 (A, D, G, and J), Mig (B, E, H, and K), or SDF-1α (C, F, I, and L) is shown. CD34⁺ hematopoietic progenitors from human cord blood were either freshly isolated (A-C), stimulated with GM-CSF (D-F), incubated with anti-CXCR3 mAb and stimulated with GM-CSF (G-I), or incubated with isotype mAb and stimulated with GM-CSF (J-L). Arrows indicate the aggregation clusters. The cells were photographed at ×100 magnification. Aggregation in A, B, G, and H was estimated to be 0; that in D, E, F, I, J, and L to be 2+ to 3+; and that in C and K to be 4+. The photographs are representative of 3 similar experiments.