August 19, 2015

Exposing the immune system

MELBOURNE, WEDNESDAY 19 AUGUST 2015: Scientists have successfully imaged the immune response at the cellular level, laying the groundwork for significant medical advances.

A team of Australian researchers from the University of Melbourne has visualised for the first time how immune cells are activated and work together to fight off a virus infection. Co-authored by Imaging CoE scientists, Dr Scott Mueller and Professor William Heath, the new study has revealed the interactions involved in priming an immune response – and the findings could be used to improve current vaccines, bringing hope to thousands of people at risk of chronic and deadly diseases.

CD4 T cell clustering with migratory DC during early HSV-1 infectionTasked with keeping the body safe, the immune system is made up of a complex network of organs, tissues and cells. Although many studies have looked at how an immune response is initiated, very little is known about the way individual cells in the immune system coordinate themselves to fight off infections. This is because we have never been able to see this phenomenon occurring – until now, that is.

Using highly sophisticated microscope technology, the team imaged the cells of the immune system in real time within the tissues of mice. Remarkably, they were able to make movies of the three major white blood cell players involved in initiating the immune response to Herpes Simplex virus infection: dendritic cells, killer T cells and helper T cells. Dendritic cells capture antigens and present them to T cells, effectively flagging them up for attack. Killer T cells hunt down and destroy cells that have become infected or that are cancerous, while helper T cells are involved in orchestrating the immune response.

“We discovered that the immune cells make a series of interactions, like a tag team, with the helper T cells first responding and then assisting the killer T cells,” says Mueller, who is an Associate Investigator at the Imaging CoE. “Revealing this dynamic immune cell dance for the first time explains how the immune system can respond so quickly to an infection on the skin.” The study also highlighted a previously unidentified level of control of T cell activation to peripheral infection.

The scientists are now planning to dig more deeply into the mechanisms of the immune system, and explore how helper T cells go about delivering their help to the killer T cells via the dendritic cells. They will also explore the importance of the dynamic interactions they observed in this study, and how they affect the immune response as a whole.

By showing us how immune cells behave, and providing an insight into the critical steps required to stimulate immunity, the team’s discovery could lead to useful applications in medicine. “Armed with knowledge of how the immune cells behave, we may be able to improve responses to diseases such as HIV, or alternately disrupt immune cell interactions where they are not wanted, such as during autoimmune diseases” Mueller says.

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The paper has been published in the high-profile journal Immunity.
http://www.cell.com/immunity/abstract/S1074-7613(15)00309-X

FOR INTERVIEW:
Dr Scott Mueller
Professor William Heath

CONTACT:
Stephanie Pradier
0424 568 314
stephanie.pradier@monash.edu

FURTHER DETAILS:
The $39 million ARC-funded Imaging CoE develops and uses innovative imaging technologies to visualise the molecular interactions that underpin the immune system. Featuring an internationally renowned team of lead scientists across five major Australian Universities and academic and commercial partners globally, the Centre uses a truly multi scale and programmatic approach to imaging to deliver maximum impact.

The Imaging CoE is headquartered at Monash University with four collaborating organisations – La Trobe University, the University of Melbourne, University of New South Wales and the University of Queensland