International Day Of Immunology 2025: Brain And Immunity (2025)

According to Professor Kjesten Wiig, Director of theMalaghan Institute, the future of brain research lies inneuroimmunology. As a trained neuroscientist, she explainshow this fast-rising field could transform how we understandneurological disorders like Alzheimer’s, Parkinson’s andmotor neuron disease.

Few conditions inspire moredread than the creeping shadow of neurodegenerative disease.At times, it feels almost taboo to talk about, perhapsbecause it touches on something deeper than physicaldecline. We fear the loss of our mental faculty because itthreatens the very core of who we are; our memories, ourrelationships, our sense of self. What makesneurodegenerative disease more unsettling is just how littlewe understand about these diseases and how few tools we haveto stop them.

So how can we protect our brains fromdecline and retain our health for longer? I believe theanswer lies in our immune system.

An unseenalliance

The brain is a unique organ, isolated fromthe rest of the body through the blood-brain barrier, aprotective mechanism that separates the brain from thebody’s blood supply. The barrier allows essentialsubstances like oxygen and glucose to pass through, butkeeps out potentially harmful substances that might lurk inthe blood like bacteria and viruses.

The blood-brainbarrier keeps the brain stable and safe, but it’s adouble-edged sword. The barrier also keeps out many drugsand immune cells needed to fight diseases that occur in thebrain. This has made neurological diseases especiallydifficult to treat and study, as any therapy must firstovercome this stubborn hurdle.

For decades, the brainwas believed to function outside the reach of the immunesystem. But that notion is now outdated. There is an unseenalliance between the brain and a few privileged immunecells, and this relationship could hold vital clues toconditions such as Alzheimer’s, Parkinson’s, motorneuron disease and even mental health disorders.

Aunique immune environment

The brain’s immuneenvironment is unlike any other found in the body. It iscarefully regulated, home to a specialised network of immunecells embedded within a complex web of neurons and glialcells. Chief among these immune cells are microglia, thebrain’s resident sentinels. They constantly monitor theirsurroundings, clear waste and help maintain healthycommunication between neurons.

Discoveriessuch as direct signalling between immune and neural cellshave reshaped our understanding of how the brain maintains ahealthy balance and responds toinjury.

But this balance is delicate.Infections, stress and ageing can offset it, leading toinflammation that gradually erodes brainfunction.

From the subtle but compounding shifts thatcome with age, to potential therapies that retrain immuneresponses, the line between neurological and immune healthis becoming increasingly blurred. More and more, theseconditions are touching people of all ages and walks oflife. While the diseases may differ, from neurodevelopmentaldisorders in childhood to dementia in later life, theinsights emerging from neuroimmunology could hold relevanceacross this entire spectrum.

An urgentopportunity

At the Malaghan Institute, we believeneuroimmunology is one of the most exciting and urgent areasfor research and discovery. With some of the country’s topimmunologists and cutting-edge tools at our fingertips, weare uniquely positioned to explore this uncharted territory,forging collaborations with researchers across Aotearoa andglobally.

Together, we have the potential to uncovertransformative ways of protecting the brain and to offerreal hope to those affected by neurological conditions. Theneed for action is clear, and the opportunity before us istoo important toignore.

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