Immune system stem cells to help grow thymus

In a world first, Monash University researchers have discovered immune system stem cells and have used them to grow a crucial part of the immune system - the thymus.

The thymus is a small organ that is critical in generating many vital cells of the immune system, including infection-fighting T-cells. In some people the thymus does not work properly due to ageing, attack by viruses, chemotherapy or genetic abnormalities. When this happens, the body becomes susceptible to infection and death can result.

But Associate Professor Richard Boyd and Dr Jason Gill from the Monash University Medical School have identified a small population of cells that can generate a complete and functional thymus.

"A major question in immunology has been how to build a thymus," Ass. Prof. Boyd said. "There are two major parts to the thymus, lymphocytes and the epithelium. It has been known for about 30 years that haemopoetic stem cells lead to the lymphocytes but, until now, we have not known which cells lead to the creation of the epithelium."

The thymus epithelium is vital in the immune response because it has the unique ability of converting haemopoetic stem cells to T-cells, Ass. Prof. Boyd said. It also controls the ability of T-cells to recognise foreign invaders and assists in stopping T-cells from attacking body tissues. If there is a defect in the thymus then there is a defect in the T-cells and a greater predisposition to disease.

Ass. Prof. Boyd said he hoped the research would eventually be used to repair or renew the thymus of people in whom it has been damaged.

Item provided courtesy of Monash University