A possible role for taste receptor cells in surveying the oral microbiome

Abstract

Taste receptor cells are sensory specialists that detect chemicals in food and drink. An exciting new report in PLOS Biology suggests that some taste cells could also be involved in immune surveillance like counterparts in the intestine.

Fig 1. Microfold (M) cell surveillance of the microbiota and a similar potential role for taste cells on the tongue.

(A) The gut microbiota is sampled by M cells that deliver bacteria and viruses across the epithelial layer to underlying immune cells, triggering immune responses or tolerance in the mucosa. The M cell pocket is occupied by a B lymphocyte that directs the maturation of M cell function. (B) Heterogeneous groups of taste cells on the tongue form taste buds surrounded by epithelial cells. Unlike M cells, taste cells are tipped by microvilli projecting into the oral cavity. A new study by Qin and colleagues demonstrates that sweet- and umami-sensing T1r3+ cells also express signature M cell genes such as the transcription factor, Spib. Wild-type taste buds take up fluorescent latex beads similar to M cells but uptake is reduced in Spib KO taste buds. Immune cell density under taste buds is also diminished in the absence of Spib. Whether taste cells can transport beads or microbes to immune cells and trigger immune responses remains to be tested. Intriguingly, Spib KO mice had increased licking responses to sucrose and umami tastants though the significance of taste changes is unknown. This exciting new study indicates a novel role of some taste cells in sampling the oral microbiome in homeostasis and during infection. This figure was created with BioRender.com.