Human NK cells express mRNA for the α7, α4, and β2 nAChR subunits. Expression of α7, α4, and β2 nAChR subunits mRNA was assessed in human NK cells by RT-PCR. A, C, and E, transcripts of α7, α4, and β2 nAChR subunits were detected by electrophoresis in agarose gel as bands of 75, 121, and 136 bp, respectively (arrows); M, DNA ladder (50 bp (A) and 100 bp (C and E)); 1, PCR negative control; 2, PCR positive control (A, human α7 cDNA; B, human α4 cDNA; C, human β2 cDNA); 3, human NK cells. B, D, and F, relative quantification (RQ) of mRNA expression of α7, α4, and β2 nAChR subunit mRNA in human NK cells incubated with and without IL-12, IL-18, and IL-15 for 48 h. qPCR was carried out as described under “Experimental Procedures.” The results are the mean ± S.E., and are cumulative of at least three independent experiments performed with NK cells from different donors (n = 3–5). *, p < 0.05; ***, p < 0.001; paired t test.