February 15, 2016

New population of human T cells

Researchers from the Imaging Centre of Excellence in collaboration with a team from the Peter Doherty Institute for Infection and Immunity (Doherty Institute) have discovered a new population of disease-fighting T Cells in the human immune system.

The study, published in Immunity today, found that while these cells were a close relative of mucosal-associated invariant T (MAIT) cells that recognise bacteria such as mycobacterium tuberculosis and E. coli, they differed in the types of foreign molecules or antigens they can detect.

Imaging CoE CI Dale Godfrey, based at the Doherty Institute, explains that while MAIT cells typically detect vitamin B2 (riboflavin) metabolites produced by various types of bacteria, the new cells detect derivatives of vitamin B9 (folate) — an essential dietary component — and may harness the ability to recognise other common antigens that are structurally related to these molecules.

“These findings provide valuable new insight into the types of cells that comprise the human immune system, the various antigens they can recognise and therefore the types of diseases they may protect us from,” Godfrey says.

“The next phase of our research will be to test whether they’re elevated, altered or depleted when presented with infectious and non-infectious diseases, with the aim of ultimately determining how they might be manipulated to fight disease.”

Co-senior author CI Jamie Rossjohn, Monash University, says: “Using the Australian Synchrotron here in Melbourne, we provided insight into the molecular basis underpinning these responses.

“Collectively, this work potentially suggests a broader role for MAIT cells in the immune system, including in diseases of non-microbial aetiology.”

Sharon Lewin, Director of the Doherty Institute, concludes: “We know a lot about the immune system, but there are still many pieces of this very complex puzzle that are missing – as identified by this study.

“This paper is a valuable addition to a series of pioneering studies on MAIT cells by a collaborative network of Australian researchers including teams headed by Imaging CoE CIs Godfrey, Rossjohn and David Fairlie, who is based at the University of Queensland, and James McCluskey, Deputy Vice Chancellor of Research, the University of Melbourne.