Flow cytometric analysis of the expression of iNOS in PB-NK and S-NK cells treated with IL-2 in the presence or absence of iNOS-antisense. AS, antisense oligodeoxynucleotide against iNOS mRNA; Scr, scrambled oligodeoxynucleotide. Fluorescence intensity of permeabilized cells stained with an irrelevant primary antiody plus a secondary antibody was not significantly different from that incubated only with the secondary antibody (not shown). Results shown are representative of three separate experiments.