An IL-23R/IL-22 Circuit Regulates Epithelial Serum Amyloid A to Promote Local Effector Th17 Responses

Identifying species of symbiont bacteria from the human gut that, alone, can induce intestinal Th17 cells in mice

“…1C), despite a significant induction of RORγt in Foxp3 − CD4 + T cells (Fig. 1E), implying a disjunction between RORγt expression and cytokine production (26). Indeed, the proportion of RORγt + T cells producing IL-17A was diminished in the colon relative to the small intestine (Fig.…”

“…5C, Upper). RNAs specifically enriched in the intestines of SFB + mice included several previously imputed to SFB, such as MHC-II transcripts (40) and mRNAs encoding molecules that augment Th17 responses (e.g., the serum amyloid A family of proteins), Duox2, and Duoxa2 (11,26) (Fig. 5A, blue symbols).…”

Do the Microbiota Influence Vaccines and Protective Immunity to Pathogens?

“…In skin, CD8 T-cell responses are elicited by Staphylococcus epidermidis and, while similar responses have not been investigated in detail in the intestine, they clearly do exist, as shown recently in mice colonized with microbiota from pet store animals rather than from mice in specific pathogen-free facilities (Naik et al 2015;Beura et al 2016). In addition, some bacteria and helminths induce distinct cytokine responses by epithelial and myeloid cell subsets, resulting in activation of distinct subsets of innate lymphoid cells (Sano et al 2015;Howitt et al 2016). Together, these responses contribute not only to local barrier enforcement or wound healing, but also to systemic immune system modulation that can have either beneficial or detrimental outcomes.…”

The Microbiome: Current and Future view of an Ancient Paradigm

“…Provocative recent work has been instrumental in characterizing specific members of the microbiota that may have direct immunoregulatory function. For example, the segmented filamentous bacteria have a particularly potent ability to induce Th17 T-cell subsets in mice [1]. Identification of such associations suggests the tantalizing possibility of exploiting specific bacteria to rationally modulate adaptive immune regulatory networks.…”