CD16-positive human peripheral blood natural killer cells constitutively bind sVCAM-1.

Human peripheral blood lymphoid cells were isolated as described in “Materials and Methods”. Cells were resuspended in Tyrode's buffer containing 1 mmol/L, CaCl₂, 1 mmol/L MgCl₂, and 0.1% BSA. In the presence or absence of the function blocking anti-α4 mAb HP2/1 (10 μg/mL), 7 Ig-domainVCAM-Ig (20 μg/mL) was added, and cells were incubated for 30 minutes at room temperature. After they were washed, cells were incubated with FITC-anti-CD16 mAb.^3G8 Binding of VCAM-Ig was detected with PE-conjugated donkey antihuman IgG as described in “Materials and Methods.” The percentage of cells in quadrants is indicated. Results are representative of 3 separate experiments.