Regulation of chemokine receptor expression by various cytokines and chemokines.
In panel A, highly purified (> 97% CD16+) NK cells (1 × 106/mL) were incubated with either culture medium (CM), 15 μg/mL IFN-γ, or 20 ng/mL TGF-β, MIP-3β, SDF-1α, MDC, TARC, or I-309 for 5 days at 37°C. The cells were extensively washed and then examined for the presence of the specific chemokine receptor in the flow cytometer. Numbers indicate the percentage of positive cells expressing either CXCR3 or CXCR4. The expression of these receptors prior to activation, and 5 days after activation with the various ligands, is shown. In panel B, either 1 ng/mL of SDF-1α (left panel) or 25 ng/mL of IP-10 (right panel) was placed in the lower wells of Boyden chambers. NK cells (4 × 105) incubated for 5 days with CM, 15 μg/mL IFN-γ, or 20 ng/mL TGF-β1, MIP-3β, MDC, TARC, or I-309, were placed in the upper wells. Migration index was determined by dividing the cells migrating in the presence of chemokines or cytokines by those migrating in the absence of ligands (control).
