Search Results (2)

Immunoglobulin A (IgA), as the most secreted immunoglobulin in the intestine, plays an irreplaceable role in mucosal immunity regulation. Previous studies have indicated that Lactobacillus showed strain specificity in stimulating the secretion of IgA through intestinal mucosal lymphocytes. The reason for this phenomenon is not clear. The current studies have been aimed at exploring the effect of a strain on the secretion of IgA in the host’s intestine, but the mechanism behind it has not been seriously studied. Based on this, we selected five strains of Lactobacillus fermentum isolated from different individuals to determine whether there are intraspecific differences in stimulating the secretion of IgA from the intestinal mucosa. It was found that IgA concentrations in different intestinal segments and faeces induced by L. fermentum were different. 12-1 and X6L1 strains increased the secretion of IgA by the intestine significantly. In addition, different strains of L. fermentum were also proven to have different effects on the host gut microbiota but no significant effects on IgA-coated microbiota. Besides, it was speculated that different strains of L. fermentum may act on different pathways to stimulate IgA in a non-inflammatory manner. By explaining the differences of IgA secretion in the host’s intestine tract stimulated by different strains of L. fermentum, it is expected to provide a theoretical basis for the stimulation of intestinal secretion of IgA by Lactobacillus and a new direction for exploring the relationship between Lactobacillus and human immunity. Full article

High levels of immunoglobulin A (IgA)-coated bacteria may have a role in driving inflammatory bowel disease (IBD). We therefore investigated the effect of sodium butyrate on microbiota in IBD prone interleukin (IL)-10^−/− mice. At 8 weeks of age, mice were allocated into three groups (n = 4/group): normal (C57BL/6), IL-10^−/−, and IL-10^−/− treated with sodium butyrate (100 mM). Severity of colitis, inflammatory cytokine and short-chain fatty acid (SCFA) concentration in proximal colon contents, the percentage of IgA-coated bacteria and microbiota composition by 16S ribosomal RNA assessment of stool were measured after 4 weeks of treatment. Sodium butyrate ameliorated histological colitis and decreased levels of tumor necrosis factor (TNF)-α and IL-6 in IL-10^−/− mice compared with those without treatment. At the phylum level, a reduction in Bacteroidetes and an increase in Firmicutes in IL-10^−/− mice treated with sodium butyrate were observed. Additionally, Prevotellaceae species were reduced in IL-10^−/− mice treated with sodium butyrate as compared with those without treatment. The level of biodiversity was slightly increased and the amount of IgA-coated bacteria decreased in IL-10^−/− mice treated with sodium butyrate compared with those without treatment. Our results indicate that sodium butyrate protects against colitis, possibly through modifying the gut microbiota, enriching biodiversity and reducing the amount of colitogenic IgA-coated bacteria in IL-10^−/− mice. Full article