IMMUNOLOGY2026™ Conference Recordings For Attendees-Thetis cell regulation of intestinal tolerance

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Video Summary

The speaker described research on a specialized family of antigen-presenting cells in the gut, called theta cells (TCs), that help drive immune tolerance early in life. The team found that these cells are especially abundant around two weeks after birth, matching a critical window when the microbiota expands and when infants begin transitioning to solid food. Within this family, TC4 was identified as the key tolerogenic subset because it expresses integrin beta-8, which activates latent TGF-beta and promotes peripheral regulatory T cell (Treg) differentiation.  <br /><br />Using mouse models, the researchers showed that removing MHC class II or integrin beta-8 from RORγt-expressing cells severely reduced gut Tregs and led to colitis or impaired oral tolerance. They also found that TC4 cells are enriched in gut lymph nodes but largely absent from skin-draining lymph nodes, helping explain why the gut is uniquely tolerant to food antigens while skin exposure can trigger allergy.  <br /><br />The talk also traced TC development back to a lymphoid lineage distinct from classical dendritic cells, identifying a common TC-LTI progenitor and transcriptional regulators such as PU.1. Overall, the work supports a model in which distinct APC subsets are specialized for either tolerance or inflammation, shaping immune responses to food, microbiota, and allergens.

Meta Tag

Date April 16, 2026 10:42 AM - 11:15 AM

Room 253

Session Major Symposium A: Early Life Immune Development and Function

Speaker Chrysothemis Brown

Track Hematopoiesis and Immune System Development (HEM)

Year 2026

Keywords

theta cells

gut immune tolerance

TC4

integrin beta-8

TGF-beta activation

regulatory T cells

oral tolerance

April 16, 2026 10:42 AM - 11:15 AM

253

Major Symposium A: Early Life Immune Development and Function

Chrysothemis Brown

Hematopoiesis and Immune System Development (HEM)

2026