Red blood cells (red) and platelets (orange) amidst different immune cells. The newly discovered cell belongs to the family of lymphocytes, here depicted in blue.
Credit: STEVE GSCHMEISSNER / SGS / Science Photo Library
LONDON: A new type of white blood cell that plays an important role in the immune system has been discovered by Australian scientists.
This research, published in the current issue of Nature Immunology, could improve our understanding of conditions such as infections and cancer, and may help develop new therapies for these diseases.
"The discovery of these cells was accidental," said Adam Uldrich, a biomedical researcher at the University of Melbourne and one of the investigators in the study.
"We observed a population of cells that we did not expect to find. After additional tests, we became convinced that we had discovered a new population."
How immune cells sense their enemy
The immune system consists of a wide variety of white blood cells that work together in complex, precise ways - somewhat like clockwork - to protect our body from infections with viruses and bacteria.
A large family of immune cells, called T-cells, have special receptors on their surface to identify invading germs. The parts of microbes that most T-cells receptors recognise are small proteins, called peptides.
Some T-cells however, so-called NKT cells, recognise other types of molecules known as glycolipids. Albeit only a small population, NKT cells are able to strongly influence an immune response.
Discovering unknown cell
The collaborative team, led by Dale Godfrey from the University of Melbourne, Jamie Rossjohn from Monash University and Mark Smyth from the Peter MacCallum Cancer Centre, both in Melbourne, has discovered a previously unknown type of NKT cells, called V-alpha-10 NKT cells, which recognise specific glycolipids found in bacteria.
The researchers noticed a small population of NKT cells in the thymus and liver of genetically modified mice that were previously thought to not have any NKT cells.
They extracted the cell population from these animals and investigated molecules on the cells' surface.
Synchrotron fast-tracking research
Parts of their research were conducted with the help of the Australian Synchrotron, a light source facility in Melbourne that makes it possible to study in detail the 3-dimensional (3D) structure of tiny molecules.
"The Australian Synchrotron is a fantastic facility that is fast-tracking many areas of scientific research, and is run by a qualified group of core staff that work around the clock and also provide on-site training for scientists wishing to use the facility", said Uldrich.
Together with his co-investigator, Onisha Patel from Monash University, Uldrich used the Synchrotron resources to study the precise molecular structures and mechanisms by which the T-cell receptors of the new NKT cell subset bind bacterial glycolipids.
