Using the only microscope of its kind in Australia, a group of Australian scientists on Monday said they have been able for the first time to see the inner workings of T-cells, and discovered a crucial feature that enables T-cells to function.
T-cells is the front-line troops, which alert our immune system to go on the defensive against germs and other invaders in our bloodstream.
T-cells need to be switched on in order to perform their protective role. The long-standing question has been: how?
For the first time the team at the University of New South Wales, led by Associate Professor Katharina Gaus and PhD candidate David Williamson, have reveal a crucial feature that enables T- cells to function.
Using the microscope, they found that the signalling was not operating through Lat on the surface of the T-cells, as originally suspected.
The scientists instead, found that when T-cell antigen receptors were triggered, it resulted in the recruitment of Lat from vesicles within the cell, which act as the signalling transporters.
"Previously it was thought that T-cell signalling was initiated at the cell surface in molecular clusters that formed around the activated receptor," Professor Gaus said in a statement released on Monday.
"In fact, what happens is that small membrane-enclosed sacks called vesicles inside the cell travel to the receptor, pick up the signal and then leave again."
Professor Gaus said the discovery of team overturns what was previously understood of T-cells, and the discovery explained how the immune response could occur so quickly.
"There is this rolling amplification. The signalling station is like a docking port or an airport with vesicles like planes landing and taking off. The process allows a few receptors to activate a cell and then trigger the entire immune response," she said.
She said the breakthrough could lead to treatments for a range of conditions from auto-immune diseases to cancer.
Williamson said the next step was to pinpoint other key proteins to get a complete picture of T-cell activity, and to extend the microscope to capture 3-D images with the same unprecedented resolution.
"Being able to see the behaviour and function of individual molecules in a live cell is the equivalent of seeing atoms for the first time. It could change the whole concept of molecular and cell biology," Williamson said.
The findings have been published in the scientific journal, Nature Immunology.