Immunomodulation by Bifidobacterium infantis 35624 in the Murine Lamina Propria Requires Retinoic Acid-Dependent and Independent Mechanisms - PMC
Appropriate dendritic cell processing of the microbiota promotes intestinal homeostasis and protects against aberrant inflammatory responses. Mucosal CD103+ dendritic cells are able to produce retinoic acid from retinal, however their role in vivo ...

Double blind, placebo controlled trial of two probiotic strains in interleukin 10 knockout mice and mechanistic link with cytokine balance - PMC
Background: Prophylactic efficacy against colitis following lactobacillus consumption in interleukin 10 (IL-10) knockout (KO) mice has been reported. Whether this applies equally to other probiotic strains is unknown, and the mechanism is unclear. ...

I once saw a person who had a fecal matter transplant and recovered a large part of his hair. Since then, I've been interested in probiotics. I got that from GPT chat.
But if you, who have more knowledge, could go into more detail, I would be grateful.