In my last snippet, I wrote about a preprint on antimicrobial peptides as sleep modulators, which got me thinking more generally about interactions between the immune system and behaviour. Growing evidence shows extensive immune system-to-brain signalling and indicates that behavioural changes (like sleeping more and eating less) are not just side effects of being ill. There’s also evidence of signalling going the other way – from brain to immune system (e.g., stress modulates immunity), although this is less well understood.
A fascinating study published recently in Nature Neuroscience provides new insights into brain-to-immune system signalling by showing that the mere threat of an infection can induce an immune response. The researchers used virtual reality to mimic encounters with visibly sick people (using avatars with e.g., coughs or rashes) and observed activation of immune cells called innate lymphoid cells (ILCs) similar to the activation seen upon flu vaccination. Importantly, they showed that ILCs were activated only in response to an infection threat and not a generic threat.
It’s clear that there is still much to be discovered about the two-way signalling between the immune system and the brain.
Neural anticipation of virtual infection triggers an immune response
In Nature Neuroscience, September 2025
From the groups of Camilla Jandus (University of Geneva, Switzerland) and Andrea Serino (University Hospital of Lausanne, Switzerland)
Snippet by Katrina Woolcock
Image credit: Figure 2a from Trabanelli et al. cited above (CC BY 4.0).