The bitter taste of gram-negative infections

Key words: Innate immunity, Quorum sensing, T2R bitter taste receptors, TAS2R38

Recently, an increasing number of reports about the presence of taste receptors in extra oral tissues have suggested that these molecules should play additional roles apart from taste perception. It is evident that molecules that act as tastants in the oral cavity may serve as agonists for the same receptors also in non-gustatory tissues. Nutrient sensing within the GI tract might exert important regulatory roles in digestive and metabolic processes with relevant implications in functional GI disorders. Over the past two years it has become increasingly clear that the bitter taste receptor family T2R, expressed in ciliated epithelial cells of the respiratory tract, is able to detect bacterial products and to stimulate innate defences against pathogens. Recent clinical studies have suggested that genetic variations in a particular T2R isoform (TAS2R38), acting as ligand for quorum sensing molecules secreted by Gram-negative bacteria, are associated to susceptibility to severe upper respiratory infections.