Analysis of surface CCR7 expression on DCs and of CCR7 mRNA on NK cells after coculture with 221 cell line. (A-B) Both immature and mature DCs were analyzed by immunofluorescence for the expression of CCR7 (A). (B) NK cells that had been cocultured with the 221 cell line were isolated by cell sorting and analyzed by RT-PCR for CCR7 expression compared with the 221 cell line and polyclonal NK cells. NK cells used for cocultures in these experiments were represented by polyclonal IL-2–activated populations that were homogeneously characterized by a CCR7-negative surface phenotype. PCR products were run on a 0.8% agarose gel and visualized by ethidium bromide staining. RT-PCR was also performed with primers specific for CD86, CD16, and β-actin as positive control.