Fighting infections around the clock: Searching for better defences
- AMRF
- 6 hours ago
- 4 min read
Every day, our bodies perform countless tasks without us noticing. They heal wounds. They repair tissues. They fight off bacteria and viruses before we ever know they were there. For Professor Chris Hall, one question has long captured his imagination: how does the immune system know when to be ready? The answer, he believes, could help researchers uncover entirely new ways to protect people from serious infections.
As a Professor of Immunology at the University of Auckland, Chris has spent much of his career exploring the remarkable behaviour of immune cells. Using the zebrafish, a tiny freshwater fish whose transparent larvae allow researchers to observe immune responses in real time, he has helped pioneer new ways of studying how the body responds to injury, inflammation and infection.
What drives him is the opportunity to see biology in action. Rather than studying isolated cells in a laboratory dish, Chris’ team can watch immune cells move, communicate and respond to threats inside a living organism. Those observations have already helped identify new approaches for treating inflammatory diseases and have even contributed to drugs progressing from the laboratory into clinical testing.
More recently, Chris turned his attention to a challenge that affects people around the world.
Infectious diseases remain one of the most common reasons for hospital admission in New Zealand, particularly for Māori and Pacific communities. At the same time, researchers have known for decades that the body’s ability to fight infection changes throughout the day. People who experience disruption to their natural body clock through shift work, irregular hours or jet lag can become more vulnerable to infection. Yet scientists have not fully understood why. Chris wanted to understand what was happening beneath the surface.
“If we can understand how the body’s natural rhythms influence immunity, we may be able to find new ways to strengthen antibacterial defences when they are most needed.”
Working alongside circadian biology expert Associate Professor Guy Warman and a team of young researchers and technicians, he began investigating whether the immune system contains its own internal timing mechanism.
Their research focused on what scientists call the innate immune system, the body’s first line of defence against invading bacteria.
The team’s idea was surprisingly simple: What if the immune system could anticipate danger?
Just as people set an alarm clock before an important day, what if immune cells were using a biological timer to prepare themselves for periods when infection risk is greatest?
Using their zebrafish model, the researchers found compelling evidence that this is exactly what happens. Their work showed that an important clock gene helps regulate a powerful antibacterial defence system in the liver, allowing the body to mount a stronger response during periods of activity when encounters with harmful microbes are more likely.
When that clock mechanism was disrupted, the ability to fight infection weakened. For Chris, the finding revealed a fascinating partnership between time and immunity.
“The immune system is not simply reacting to threats as they appear,” he says. “It is preparing for them. We’re beginning to see that immune cells use biological clocks to anticipate periods of greater risk and strengthen their defences accordingly.”
The discovery opened the door to even bigger questions.
Could understanding these biological clocks help researchers develop new treatments? Could healthcare providers eventually use timing to improve outcomes for patients? And could people whose natural rhythms are disrupted gain extra protection through therapies designed around the body’s internal clock?
These possibilities are part of a growing field known as chronotherapy, which explores how the timing of treatment may influence its effectiveness. Chris’ research is helping build the biological foundations needed to make those future advances possible.
Importantly, the research has continued to evolve. In 2025, Chris and collaborators published findings in Science Immunology showing that a light-responsive molecular timer helps optimise the bacteria-killing activity of neutrophils, one of the body’s most important infection-fighting immune cells. The study demonstrated how specific clock genes help synchronise stronger antibacterial activity with daytime periods when the risk of infection is highest.
While the science is complex, the underlying goal remains straightforward. Help people stay healthier.
By understanding how the body’s natural rhythms influence immunity, researchers hope to identify ways to strengthen the body’s defences when they are most needed.
This work also reflects Chris’ broader approach to science. Throughout his career, he has focused on combining fundamental discoveries with practical applications. Whether studying infection, inflammation or immune cell behaviour, he is interested in generating knowledge that can ultimately improve health outcomes.
Support from AMRF helped make this work possible. Funding enabled Chris and his team to pursue a high-risk, high-reward research question, develop specialised zebrafish models, support research staff and continue making progress despite significant disruption caused by the COVID-19 pandemic. The project also contributed to the development of emerging researchers, helping build capability within New Zealand’s biomedical research sector.
For Chris, that investment delivers benefits well beyond a single project.
“Research is often a long journey,” he says. “Each discovery builds on years of work, collaboration and curiosity. Support for fundamental science gives researchers the freedom to ask questions that may ultimately lead to entirely new ways of improving people’s health.”
Today, Chris’ team continues exploring how immune cells use internal clocks to guide their behaviour. Every new insight brings researchers closer to understanding how the body’s ancient defence systems have evolved to protect us.
And in doing so, they are revealing something remarkable.
Even when we are asleep, resting or simply going about our daily lives, our immune system is keeping time, preparing for the challenges ahead and working to keep us well. That quiet vigilance may one day help researchers unlock new ways to fight infections, improve treatments and create healthier futures for New Zealanders.
