gd T lymphocytes
What is a γδ T-cell?
Γδ T-cells are a subset of T-cells that express a TCR made from the TCRγ and TCRδ genes. They are very similar to αβT-cells, but less is known about what they recognise and what roles the play in immunity.
What is the role of γδT-cells in the immune system?
All jawed vertebrates from shark to human have γδ T-cells. Conservation of γδ T-cells throughout almost 500 million years of evolution is testament to their importance. Indeed, phylogenetic analysis of antigen receptor constant domains suggests that the γδ TCR predates the B-cell receptor (antibody) and αβ TCR. Thus γδ T-cells may be the cells that taught the immune system to adapt and ‘remember’. If indeed γδ T-cells did educate the adaptive immune system then we might expect that they could perform the roles of their evolutionary cellular descendants that form the cornerstones of antibody and αβ T-cell immunity. In support of this notion, Bernhard Moser and Matthias Eberl in our Division are finding that human γδ T-cells possess a high degree of functional plasticity. Professor Moser's laboratory published a report in Science that shows that peripheral blood γδT-cells that bear a receptor made from the Vγ9 and Vδ2 genes can be extremely effective at presenting antigen to their αβTCR expressing evolutionary descendants. We are also finding that different subsets of γδ T-cells can perform other important immune functions that until now have been assumed to be exclusive roles of other immune cells. A full understanding of the roles played by γδ T-cells awaits the discovery of the ligands recognized by γδTCRs.