Figure 5.

CD36 signaling was critical in 4,4′-diaponeurosporene-producing Bacillus subtilis (B.s-Dia)-induced immune process. (A) Mice were intragastrically administrated with 1 × 10⁹ colony forming units (cfu) B.s-Dia, and the number of B.s-Dia in mouse feces at indicated time points were detected by plate count. (B) Six hours after intragastrical administration of Dylight 488 labeled B.s-Dia, the distribution of B.s-Dia was detected by confocal microscope. B.s-Dia (green), DAPI (blue). (C) The intestinal epithelial cells (IECs) of indicated mice were digested, and the expression of CD36 on CD326⁺ IECs was measured by flow cytometry. (D) Mice were intragastrically administrated with 1 × 10⁹ cfu B.s-Dia or equal B.s-Dia combined with 200 µg sulfo-N-succinimidyl oleate (SSO) daily for 7 days. The expression of CCL20 (red) in IECs of the indicated mice was detected by confocal microscope. The staining of CD11c⁺ cells (green) was showed in below panels. Scale bar, 20 µm in above panel and 100 µm in the below panel. (E) Mice were treated as described in (C). IECs were then removed by EDTA digestion and cultured at 37°C for 6 h. And, the amount of CCL20 in supernatant was detected by ELISA. (F) Mice were treated as described in (D). On day 8, all mice were intragastrically infected with 5 × 10⁸ cfu Salmonella typhimurium. Mouse survival rate was recorded daily for 9 days. Survival curves were analyzed using a Kaplan–Meier survival analysis with log-rank tests, n = 12. Other data were analyzed via one-way ANOVA test (**P < 0.01, *P < 0.05). One representative of three similar independent experiments is shown.