New research finds immune cells vital to fight multiple diseases

SYDNEY, Aug. 18 (Xinhua) -- An international research team, including those from Australia, has discovered a new group of immune cells which they believe are vital in helping the body fight against severe infections and cancer.

Their findings, published in the Nature journal on Thursday, may explain why immunotherapy fails in some people, and could lead to the development of more effective new therapies for cancer and viruses such as hepatitis and human immunodeficiency virus (HIV).

Molecular immunologist Professor Axel Kallies, from Australia's Peter Doherty Institute for Infection and Immunity at the University of Melbourne, said those life-threatening illnesses can cause "immune exhaustion" that impacts an immune cell population known as cytotoxic T cells.

In previous studies, his team had shown that some types of T cells were able to survive their encounters with the diseases.

The latest study, done in collaboration with scientists from Germany's Technical University of Munich (TUM), has pinpointed the hardy T cell population that helps maintain the body's long-term responses.

"These cells are like the fountain of youth for T cell immunity, allowing exhausted T cells to self-renew and remain functional," said first author of the research, Dr Lorenz Kretschmer, from TUM.

The researchers have proposed this new subset of cells to be called stem-like exhausted T cells.

The team has also identified the key molecule which enables such cells to flourish.

"We discovered a specific transcription factor, called Myb, that controls the development and function of these cells," Kallies said.

"Without this factor, this population of cells doesn't form, and the T cells responding to the chronic infection cannot be maintained," he said. "Basically, without this transcription factor, immunotherapy fails."

The researchers are now working on ways to use these resilient cells with the goal of creating better therapies.

"Currently, immunotherapy is only successful in some cancers and only works for some patients," Kallies said.

"We are hopeful that our insights into the mechanisms of T cell invigoration may lead to the development of better-targeted immunotherapies to improve outcomes in the context of viral infections and cancer."