Volatile and non-volatile pathogen cues shape host extracellular vesicles production in pre-infection response

In natural environments, animals encounter pathogen-derived chemicals long before infection occurs. How such anticipatory cues influence extracellular vesicle (EV) dynamics, which are central to immune regulation, intercellular communication, and stress responses, remains unknown. Using Caenorhabditis elegans, we show that pathogen-derived volatile and non-volatile compounds trigger distinct EV pathways through separate sensory and molecular mechanisms. Non-volatile secretome components, including the tripeptide Ile-Pro-Pro, activate immune-dependent EV production, whereas volatile metabolites elicit immunity-independent EV formation. Both responses require sensory input from ASK, ADL, and AWC neurons and converge on a neural circuit involving RMG, AIB, and AIA interneurons. GPCRs SRI-19, SRI-36/39, and SRR-6 mediate non-volatile responses, with SRR-6 acting in the intestine to regulate muscle EVs release. Notably, pre-exposure to pathogen volatiles enhances offspring survival during subsequent infection in an SRI-19-dependent manner, suggesting a predictive, intergenerational benefit of pathogen detection. In summary, our findings uncover that pathogen-derived chemical cues shape host EV production via specialized sensory circuits, revealing how animals anticipate infection and prime protective physiological responses.