(A) C57BL/6 pregnant dams were gavaged with P. UF1 or PBS twice/week during gestation. Five days after birth, newborn mice were sacrificed. Representative data of flow plots, percentages, and total cell counts of Th17 cells and IL-10⁺TGF-β⁺ Tregs in newborn mice. Each dot represents 3 pooled small intestinal tissues from each group of newborn mice. (B and C) Five days after birth, newborn mice of dams gavaged with P. UF1 or PBS were separated and subjected to NEC-like injury. Newborn mice gavaged with PBS or P. UF1 (10⁷ CFU/mouse) on days 1, 3, and 5. Newborn mice were sacrificed 6 days later. Survival curve and weight incidence of the newborn mice subjected to NEC-like injury (B), and representative H&E sections of the small intestine of control newborn mice (PBS) or mice subjected to NEC-like injury with or without P. UF1. (C) Original magnification, ×10. (D) qRT-PCR demonstrating expression of proinflammatory genes in the small intestine of P. UF1–gavaged or untreated newborn mice subjected to NEC-like injury. Control newborn mice (PBS) with no NEC-like injury. (E and F) Representative data of flow plots, percentages, and total cell counts of IL-1β⁺, IL-6⁺, IL-12/23p40⁺, IL-10⁺, and TGF-β⁺ DCs (E), IL-10⁺ Th17 cells, and IL-10⁺ TGF-β⁺ Tregs (F) in the indicated groups. Data are pooled from 3 experiments in steady state (n = 15 newborn mice/group, A) and for NEC-like injury (PBS, n = 10 newborn mice; NEC, n = 12 newborn mice; NEC + P. UF1, n = 17 newborn mice, E) or 4 experiments (NEC, n = 33 newborn mice; NEC + P. UF1, n = 30 newborn mice, B). Error bars represent mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, 2-tailed unpaired t test (A and B) or Kruskal-Wallis test (D–F).