MHC molecules in the vomeronasal organ: contributors to pheromonal discrimination?

The vomeronasal organ of the accessory olfactory system detects pheromones in several vertebrate species. Recent studies of vomeronasal sensory neurons have shown that they express MHC molecules, which in the immune system help to discriminate self antigens from non-self antigens. These new findings, along with past research demonstrating MHC-based olfactory discrimination, suggest the exciting possibility that MHC molecules together with vomeronasal G-protein-coupled receptors play a role in distinguishing related individuals from unrelated ones based on pheromonal cues.