Fig. 4.

Maternal and host-derived ICOSL-dependent antibodies in combination with IL-10 help to promote intestinal immune homeostasis in early life. (A) Longitudinal Lcn-2 levels detected in feces of Icosl^+/+, Icosl^−/−, Icosl^+/+.Il10cKO, and Icosl^−/−.Il10cKO mice from 4 to 7 wk of age. (B) Histopathological scoring of hematoxylin and eosin–stained sections and (C) representative photomicrographs from mice of all four genotypes analyzed at 8 wk of age; n = 8 mice/group (20× magnification). (D) Experimental design for cross-fostering experiments featuring Icosl^+/+ and Icosl^−/− mice with (solid line) or without (broken line) mutations associated with condition deletion of Il10. Graphs summarizing (E) Fecal Lcn-2 at 3 and 7 wk and (F) histopathological scores at week 7; n = 8 to 13 mice/group. Scatter plots show levels of serum and luminal IgA (G), serum and mucus IgG (H), and serum IgG1, IgG2b, IgG2c, and IgG3 (I) for 3-wk-old Icosl^+/+ and Icosl^−/− pups housed as described in F. n = 5 to 11 mice/group. For all graphs, error bars represent mean ± SD. P values were calculated by ANOVA followed by Tukey’s multiple comparisons test; *P < 0.05, **P < 0.01, ***P < 0.001. Data are representative of two (A–C) or four (D–I) experiments.