IMMUNOLOGY2025™ Conference Recordings-Memory T cells in tissues

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Video Summary

The speaker described evidence that T cells are present in human brains and may increase with age or neurological disease, but their origin and function are unclear. To study this, the lab used “dirty” mice exposed to pathogens through co-housing or sequential infections, making their immune systems more human-like than standard SPF mice. These exposures increased CD4 and CD8 T cells in multiple brain regions, including the choroid plexus, white matter, gray matter, and cerebrospinal fluid spaces. Many of the cells showed a resident memory phenotype, recognized specific pathogen antigens, produced cytokines such as IFN-γ and TNF, and interacted with microglia and other brain cells. In an epilepsy model, pathogen-exposed mice had longer seizures, and this effect was reduced by T-cell depletion or TNF neutralization. The findings suggest microbial exposure shapes a resident brain T-cell population that can alter brain physiology and may influence neurological disease.

Keywords

T cells

brain immunity

resident memory T cells

microglia interaction

pathogen exposure

neurological disease