The influence of rhSDF-1α on growth and development of human thymocytes can be neutralized by anti–SDF-1 antibodies.

(A) FTOC carried out as described in “Material and methods” were cultured in the presence of rhSDF-1α (10 ng/mL) and different doses of neutralizing anti–SDF-1α antibodies. The numbers of human cells recovered per lobe after 18 days of treatment are shown (solid line). Cell number in control FTOC is also indicated (•). (B) FTOC were cultured with anti–SDF-1α (5 μg/mL) in the absence or presence of rhSDF-1α (10 ng/mL) for 18 days. Cells expressing human CD45 antigen were gated and the expression of CD4, CD8, and CD3 antigens is shown for this gated population. Results are representative of 2 different experiments.