Mice Fed Soy Gain Two Gut Bacteria and a Stronger Mucosal IgA Response
A dietary component grew specific commensal bacteria, which split the roles of providing antigen and an adjuvant signal to build the gut mucosal antibody response.
Immunoglobulin A (IgA) in the gut mucosa is an antibody that guards the gateway where food and bacteria pass through. This response depends on commensal bacteria, but it was unclear where in that chain diet intervenes. Researchers at Keio University in Japan reported in Immunity a study of mice at weaning that traces the link from diet to bacteria to immunity.
Two bacterial species divide the roles
In mice fed soy, follicular helper T (Tfh) cells and IgA production clearly increased in the Peyer's patches, the gut's immune tissue. At the same time, two commensal bacterial species, Limosilactobacillus reuteri and Muribaculum intestinale, expanded.
The roles were divided. L. reuteri supplied the antigen that awakens Tfh cells, while Muribaculum induced interleukin-1 beta (IL-1β) production in myeloid cells and acted like an adjuvant. The IgA produced this way showed polyreactivity, binding broadly to many antigens, and strengthened defence against Salmonella infection.
Limitations
This was a mouse experiment, with results observed at a specific stage, weaning. It has not been confirmed that the same diet-bacteria-immunity link operates in people, and it cannot be taken as grounds for eating a particular food or supplement.
- A soy diet increased Tfh cells and IgA production in the Peyer's patches of weaning mice
- L. reuteri provides antigen and M. intestinale induces IL-1β, splitting the adjuvant role
- The IgA produced showed polyreactivity and strengthened defence against Salmonella infection
Limitations These are results from weaning mice. Whether they apply to people has not been confirmed, and they are not grounds for eating a particular food or supplement.
Original research
- Hattori-Muroi K, Maruta H, Takahashi D, … Hase K · Keio University (Japan). Dietary soy shapes the microbiome to induce commensal-specific T follicular helper cells and IgA production. Immunity. DOI: 10.1016/j.immuni.2026.04.013
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