Sendai virus intra-host population dynamics and host immunocompetence influence viral virulence during in vivo passage

Peña, José; Chen-Harris, Haiyin; Allen, Jonathan E.; Hwang, Mona; Elsheikh, Maher; Mabery, Shalini; Bielefeldt-Ohmann, Helle; Zemla, Adam T.; Bowen, Richard A.; Borucki, Monica K.

Lung homogenates from all three diet groups were assayed for changes in cytokine gene expression according to diet group and passage number. Gene expression dynamics of cytokines Ccl3, Ifng, Il4, Il6, and Tnfa was determined using qRT-PCR. As shown in Figure 3 , basal levels of gene expression in uninfected mice were altered between FD and SD mice compared with ND mice (Fig. 3A) . Following SeV infection gene expression of Ccl3, Ifng, Il4, Il6, and Tnfa was suppressed in mice receiving a fat or selenium deficient diet compared with mice under ND conditions. Although most genes were suppressed under the various diet conditions, SD mice had a several fold increase in the expression of Il4, a Th2 response gene, compared with ND mice (Fig. 3B-D) . Additionally, analysis of gene expression changes in guinea pigs infected with P10 virus from the various diet groups yielded little to no differences in the expression levels of Ccl2, Ifng, or Il-1b compared with seed virus (Supplementary Fig. S1 ). However, the expression levels of Tnfa were between 1.5-and 2.0-fold higher in guinea pigs infected with the P10 virus inoculum from the different mouse diets groups compared with seed virus.