Figure 2

Methylation and expression of IFN-γ in T effector cells (Teffs) of all subjects. A. Comparison of overall methylation of examined cytosine nucleotide neighboring guanine (CpG) sites in IFN-γ in Teffs between Fresno subjects exposed to secondhand smoke (SHS) (FSHS) (n = 31), Fresno subjects not exposed to SHS (FnSHS) (n = 31), Stanford subjects exposed to SHS (SSHS) (n = 6), and Stanford subjects who were not exposed (SnSHS) (n = 34) groups. Methylation is reported as percent methylated CpG sites out of 6 total examined CpG sites (Figure 1); the cutoff for positive methylation at each site was set at 70% of all sequencing reactions. Error bars represent standard error of the mean (SEM). B. Comparison of expression of IFN-γ in Teffs between FSHS, FnSHS, SSHS, and SnSHS groups. Expression is reported as fold expression relative to the expression of the housekeeping gene beta-glucuronidase (GUS). Error bars represent SEM. C. Linear regression analysis of IFN-γ expression in Teffs vs. % methylation of IFN-γ from all SHS subjects. D. Linear regression analysis of IFN-γ expression in Teffs vs. % methylation of IFN-γ from all nSHS subjects. E. Linear regression analysis of IFN-γ expression in Teffs vs. % methylation of IFN-γ from all subjects. FSHS, Fresno group exposed to secondhand smoke; FnSHS, Fresno group not exposed to secondhand smoke; SSHS, Stanford group exposed to secondhand smoke; SnSHS, Stanford group not exposed to secondhand smoke; n.s., not significant. *P < 0.05.