IMMUNOLOGY2026™ Conference Recordings For Attendees-Micro-communities of microbes that modulate immune responses

Video Transcription

Video Summary

Thad Steppenbeck argued that many microbiome effects on immunity are driven not by single microbes, but by small, interacting microbial communities. He described three mouse models showing this idea.

First, a pectin-derived prebiotic gradually increased gut IgA over weeks. The effect was durable, transmissible, and could be transferred to germ-free mice. The key driver appeared to be a small Lachnospiraceae community, especially a minor member, rather than a single abundant species.

Second, he described an IgA-low phenotype caused by a rare, hard-to-detect bacterium later named <em>Thomasiella immunophilia</em>. This organism can degrade IgA but cannot easily survive alone; it depends on related microbes for growth and colonization. This again suggested that helper species are essential.

Third, he showed that checkpoint inhibitor side effects in susceptible mice were microbiome-dependent, but surprisingly driven by skin microbes rather than gut microbes. Antibiotic treatment of skin, or transferring specific skin swab communities, changed the autoimmune phenotype. The exact causal species is still unclear, though <em>Staphylococcus xylosus</em> morphotypes are a leading suspect.

Overall, his main message was that symbionts often act as micro-communities, with helper organisms enabling immune-modulating effects. Understanding these small ecosystems may be crucial for future microbiome therapies.

Meta Tag

Date April 16, 2026 9:54 AM - 10:27 AM

Room Ballroom

Session Major Symposium B: Microbiome Influence on Epithelial-immune Crosstalk

Speaker Thaddeus Stappenbeck

Track Mucosal And Regional Immunology (MUC)

Year 2026

Keywords

microbiome

immunity

IgA

Lachnospiraceae

Thomasiella immunophilia

skin microbes

checkpoint inhibitors

April 16, 2026 9:54 AM - 10:27 AM

Ballroom

Major Symposium B: Microbiome Influence on Epithelial-immune Crosstalk

Thaddeus Stappenbeck

Mucosal And Regional Immunology (MUC)

2026