Australian researchers have discovered how to prolong the life of the human body's disease-fighting cells, buying more time for cancer patients.

Researchers from Melbourne's Walter and Eliza Hall Institute of Medical Research (WEHI) working with a team from France's Centre of Immunology discovered that the BCL-2 protein was particularly important in controlling the reservoir of natural killer (NK) cells in the body.

Nick Huntington, the lead researcher from WEHI, said the team discovered the importance of BCL-2 by investigating factors that control NK cell function.

"We have been very interested in understanding which factors control the lifespan of NK cells," Huntington said in a media release issue don Tuesday.

"We had previously identified a protein related to BCL-2, called MCL-1, which was critically required for all NK cell survival. This new study now shows that BCL-2 "teams up" with MCL-1 and both these proteins crucially determine NK cell survival in our body, and the majority of NK cells died following a reduction in the levels of BCL-2.

Huntingon said by using the IL-15 protein, the population of NK cells could be increased, giving cancer patients more time for the NK cells to find and destroy cancer cells.

"Boosting NK cell numbers by treating them with IL-15 may be a valuable new approach to boosting our immunity to viral infections or cancer," he said.

"On the flipside, targeting this growth factor or BCL-2 could reduce NK cell numbers and offer potential therapies for immune disorders such as some types of autoimmune diseases, sepsis or graft versus host disease, a side effect of bone marrow transplants."