CCL3 selectively inhibits CXCL12-induced chemotaxis and adhesion to ICAM-1 of mNK cells. iNK and mNK cell migration (A) and mNK cell adhesion (B) were performed after BM cell pretreatment with or without 5 μg/mL CCL3. Cells were washed and allowed to migrate or to adhere to ICAM-1 in response to CXCL12 (used at 200 ng/mL and 5 μg/mL, respectively). iNK and mNK cell migration and mNK cell adhesion were quantified by enumerating the events contained in the NK1.1⁺/CD3⁻/DX5⁻ gate (iNK) and NK1.1⁺/CD3⁻/DX5⁺ gate (mNK) after 150-second acquisition. Data are expressed as percentage of input cells and are the means plus or minus SD of 4 independent experiments performed. (C) CXCR4 cell surface expression on iNK and mNK cells was evaluated following 45-minute BM cell incubation with CCL3 (0.5 and 1 μg/mL) or control vehicle as described in “Methods.” Left panels show histogram plot overlays of CXCR4 antibody staining of untreated (control: empty histogram) or CCL3-treated (0.5 μg/mL, gray histogram) cells. Right panel shows the geometric mean fluorescence intensity (MFI) of CCL3-treated cells expressed as percentage of control (untreated) cells. MFI of isotype control staining did not vary after treatment with CCL3 (not shown). Student t test was performed by comparing CXCL12-supported migration (A) and adhesion (B), and CXCR4 cell surface expression (C) of untreated versus CCL3-pretreated BM NK cells. *P < .05.