T cells are produced by the body to fight infection. Scientists previously identified two types of T cell, both produced in the thymus: "effector T cells", which attack infected cells, and "regulatory T cells", which suppress the immune system, protecting the body from inflammatory damage during infection. Regulatory T cells, if given to individuals receiving transplants, may help suppress the rejection response.
Now, a team of researchers has discovered a novel mechanism determining whether a maturing T cell is likely to emerge from the thymus as an effector cell or a regulatory cell. The research suggests that new treatments could be developed to deliberately affect the type of T cells produced, allowing scientists to tackle a number of diseases which are influenced by these different types of T cells.
"Our team has shown that a process known as 'trans-conditioning', which we knew to be involved in T cell development, actually has a profound influence on whether a T cell becomes an effector or a regulatory cell," explains Professor Adrian Hayday of King's College London. "This may be clinically significant; if we can find a way to influence this process, it may be possible to make the body produce effector T cells in a cancer patient or regulatory T cells in someone suffering from autoimmune disease, both of which are caused by the immune system malfunctioning."
Professor Hayday and his team believe that the findings may also answer one of medical research's mysteries: why autoimmune diseases in women commonly go into remission in pregnancy.
"We believe that trans-conditioning is less active during pregnancy," says Professor Hayday. "This means that most T cells emerging a