Olfactory sensory neurons mediate ultrarapid antiviral immune responses in a TrkA-dependent manner

Significance Many pathogens exploit the olfactory route to gain entry into the host. Olfactory sensory neurons (OSNs) are responsible for the detection of chemical stimuli in the environment but are also continuously exposed to microorganisms. Here, we report the interaction between crypt neurons (unique OSNs present in fish) and fish rhabdoviruses, an interaction that led to fast immune responses and the recruitment of nonconventional CD8 T cells to the olfactory mucosa from the olfactory bulb. These previously unrecognized antiviral immune responses required neuronal activation and depended on the interaction between the TrkA receptor expressed by crypt neurons and the viral glycoprotein protein. Our results show the importance of sensory neurons in sensing and controlling viruses that invade the nasal mucosa.