Researchers mapped the immune landscape of human gingival (gum) tissue using spatial proteomics, spatial transcriptomics, and single-cell sequencing across healthy individuals and periodontitis patients. They discovered that immune cells are not randomly distributed but form distinct anatomical zones: a dynamic epithelium at the tooth interface underlaid by a neutrophil layer, and deeper aggregates of antigen-presenting cells and lymphocytes. Even during periodontitis — a common inflammatory gum disease — this zonal organization is preserved, though zones expand and evolve into immature tertiary lymphoid structures capable of local antibody production. Stromal cells appear to direct this spatial patterning. The findings reveal a previously unrecognized 'tonic' inflammatory state in healthy gum tissue and suggest the oral barrier has unique immune wiring suited for continuous microbial exposure without systemic infection.
