Immunoglobulin A (IgA) is a major gut antibody that coats commensal gut bacteria and contributes to shaping a stable gut bacterial composition. Although previous studies have shown that cyclic oligosaccharides, including cyclic nigerosyl-1,6-nigerose (CNN) and cyclodextrins (CDs, including αCD, βCD, and γCD), alter the gut bacterial composition, it remains unclear whether cyclic oligosaccharides modify the IgA coating of gut bacteria, which relates to cyclic oligosaccharide-induced alteration of the gut bacterial composition. To address this issue, mice were maintained for 12 weeks on diets containing CNN, αCD, βCD, or γCD; the animals’ feces were evaluated for their bacterial composition and the IgA coating index (ICI), a measure of the degree of IgA coating of bacteria. It was observed that the intake of each cyclic oligosaccharide altered the gut bacterial composition, with changes in the ICI found at both the phylum and genus levels. The ICI for Bacillota, Lachnospiraceae NK4A136 group, UC Lachnospiraceae, and Tuzzerella were significantly and positively correlated with the relative abundance in total bacteria for these bacteria; in contrast, significant correlations were not seen for other phyla and genera. These observations suggest that cyclic oligosaccharide-induced modulation of the IgA coating of gut bacteria may partly relate to changes in the community structure of the gut bacteria.
Amounts of short-chain fatty acids (SCFAs) in cecal content samples. (A) Cecal content weight. Amounts of (B) acetate, (C) propionate, and (D) butyrate in cecal content samples. Data are presented as mean ± SEM (n = 6).
The current study is the first to show that the oral administration of cyclic oligosaccharides, including CNN, αCD, βCD, and γCD, distinctly alters the IgA coating profile of commensal gut bacteria in mice. The observations suggest that cyclic oligosaccharide-induced modulation of the IgA coating of gut bacteria may contribute (in part) to changes in the bacterial community structure.
Miyamoto, T.; Tsuruta, T.; Teraoka, M.; Wang, T.; Nishino, N. Cyclic Oligosaccharide-Induced Modulation of Immunoglobulin A Reactivity to Gut Bacteria Contributes to Alterations in the Bacterial Community Structure. Nutrients 2024, 16, 2824. https://doi.org/10.3390/nu16172824