Linear regression analysis of basal RF expression and resistance to infection. Basal ISG mRNA levels in (A) PBMC, (B) Duodenum, (C) ILN were calculated as described in Figure 2 and plotted versus the number of exposures required for systemic infection. Each dot indicates mean expression value of one animal. Lines depict linear regression analysis with r2 and P values indicated next to each gene. Asterisks indicate significance with P < 0.05.