Fig. 4. IL-22/IL-18 treatment prevents and treats RV infection.

(A) Eight-week-old C57/BL6 mice were treated with 0.2 ml PBS (vehicle), 2 μg IL-22, 1 μg IL-18, or 2 μg IL-22 plus 1 μg IL-18 by means of intraperitoneal injection and subsequently inoculated with RV. Such cytokines were administered every other day from 0 to 8 days after inoculation. Feces were assayed for RV antigens by means of ELISA. Results are shown as mean ± SEM. Difference between PBS and IL-22/IL-18 groups were statistically significant (two-way ANOVA, n = 4 mice, P < 0.0001). (B) Rag1^−/− mice, chronically infected with RV, were treated with PBS, 10 μg IL-22, 1 μg IL-18, or both on days 24 and 26 after inoculation (indicated with red arrows). Difference between PBS and IL-22/IL-18 groups was statistically significant (two-way ANOVA, n = 4 mice, P < 0.0001). (C) Seven-day-old C57BL/6 mice were orally inoculated with RV. Mice were administered 50 μl PBS (vehicle) or 1 μg IL-22 plus 0.2 μg IL-18 immediately before inoculation, and 1 to 9 days after inoculation, and monitored for incidence of diarrhea daily (χ² test, n = 5 to 6 mice, *P < 0.05), duration and active days of diarrhea (Student’s t test, n = 5 to 6 mice, *P < 0.001). (D to F) Chronically RV-infected Rag1^−/− mice were treated with one injection of PBS, PBS containing 10 μg IL-22, 1 μg IL-18, or 10 μg IL-22 plus 1 μg IL-18. (D) Venn diagram representation of significant changes in intestinal epithelial gene expression 3 hours after cytokine treatment. (E) Intestinal levels of RV genomes and replication rates as reflected by NSP3 RNA levels and +/− RV strand ratios at 3 hours (Student’s t test, n = 4 mice, *P < 0.001 for RV genome, *P < 0.05 for RV RNA +/− strand ratio). (F) RV genomes levels at indicated time (Student’s t test, n = 4 mice, *P < 0.0001).