Fig. 2: Respiratory IAV infection dysregulates maternal intestinal immunity in a dose- and time-dependent manner.

A IAV reduced colon length in high-dose dams as early as 2 dpi, and this persisted at 7 dpi. B Example flow cytometry gating for colonic LPLs. Gating on CD45⁺CD4⁺ T cells in the colon revealed C downregulation of IL-17F⁺ and IL-17F⁺RORγt⁺ T cells at 2 dpi which persisted into D 7 dpi in addition to downregulation of RORγt⁺ and IL-17A⁺RORγt⁺ T cells. qPCR of the ileum, the terminal end of the small intestine, confirms findings in the colon where E little changes were observed at 2 dpi and F downregulation in Il17a and Il17f was seen at 7 dpi. Notably, Rorc transcription did not coincide with decreased RORγt protein expression. G Relative gene expression via qPCR showed a decrease in SFB, a bacterial regulator of T_H17 cells, in the colon contents of high-dose dams at 7 dpi. IAV = influenza A virus, dpi = days post-inoculation, LPL = lamina propria lymphocytes, Con = saline control, X31_mod = IAV-X31 10³ TCID₅₀, X31_hi = IAV-X31 10⁴ TCID_50, SSC-A = side scatter-area, FSC-A = forward scatter-area. Groups were compared with one-way ANOVA with Tukey post hoc for multiple comparisons. For data containing residuals with unequal variance, Brown-Forsythe and Welch’s ANOVA with Dunnett T3 post hoc multiple comparisons was used. For non-parametric data, Kruskal-Wallis ANOVA with Dunn’s correction for multiple comparisons was used. Data are means ± SEM; *p < 0.05, **p < 0.01, ***p < 0.001; dots represent individual dams; n = 7–14 per treatment group. See Supplementary Tables S6–7 for complete statistical analysis of all data collected for this figure (individual mean ± SEM per group, p-values, hypothesis test used, and test statistic).