T for two: scientists show how immune system chooses best way to fight infection

14 November 2006

A new study has suggested a novel way of combating diseases related to the immune system, including cancer and autoimmune diseases such as arthritis and type 1 diabetes. The study, funded by the Wellcome Trust, appears online in the journal Nature.

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 that 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 at that time will be regulatory. Regulatory T cells prevent an over-active immune system from causing inflammatory damage to the body. This may be one of the key steps in preventing the mother from rejecting the foetus growing inside her."

The research was carried out at the King's College London School of Medicine at Guy's Hospital and was co-lead by Dr Daniel Pennington, a Wellcome Trust VIP awardee and now at Queen Mary, University of London. Collaborating researchers were based at Faculdade de Medicina de Lisboa, Lisbon; University College, London; Yale University School of Medicine; Institute for Animal Health; and Imperial College London.

Contact

Craig Brierley
Media Officer
Wellcome Trust
T +44 (0)20 7611 7329
E c.brierley@wellcome.ac.uk

Notes for editors

1. 'Early events in the thymus affect the balance of effector and regulatory T cells' by Daniel J Pennington et al.

2. The Wellcome Trust is the most diverse biomedical research charity in the world, spending about £450 million every year both in the UK and internationally to support and promote research that will improve the health of humans and animals. The Trust was established under the will of Sir Henry Wellcome, and is funded from a private endowment, which is managed with long-term stability and growth in mind.

3. King's College London is the fourth oldest university in England with more than 13 700 undergraduates and nearly 5600 graduate students in nine schools of study based at five London campuses. It is a member of the Russell Group: a coalition of the UK's major research-based universities. The College has had 24 of its subject-areas awarded the highest rating of 5* and 5 for research quality, demonstrating excellence at an international level, and it has recently received an excellent result in its audit by the Quality Assurance Agency.

King's has a particularly distinguished reputation in the humanities, law, international relations, medicine, nursing and the sciences, and has played a major role in many of the advances that have shaped modern life, such as the discovery of the structure of DNA. It is the largest centre for the education of healthcare professionals in Europe and is home to four Medical Research Council Centres – more than any other university.

King's is in the top group of UK universities for research earnings, with income from grants and contracts of more than £100 million, and has an annual turnover of more than £363 million.

4. Imperial College London is consistently rated in the top three UK university institutions. It is a world-leading science-based university whose reputation for excellence in teaching and research attracts students (11 000) and staff (6000) of the highest international quality. Innovative research at Imperial explores the interface between science, medicine, engineering and management, and delivers practical solutions that enhance the quality of life and the environment, underpinned by a dynamic enterprise culture.

5. Queen Mary is one of the leading colleges in the federal University of London, with over 11 000 undergraduate and postgraduate students, and an academic and support staff of around 2600.

Queen Mary is a research university, with over 80 per cent of research staff working in departments where research is of international or national excellence (RAE 2001). It has a strong international reputation, with around 20 per cent of students coming from over 100 countries.

The College has 21 academic departments and institutes organised into three sectors: Science and Engineering; Humanities, Social Sciences and Laws; and the School of Medicine and Dentistry.

It has an annual turnover of £200 million, research income worth £43 million, and generates employment and output worth nearly £400 million to the UK economy each year.

Queen Mary's roots lie in four historic colleges: Queen Mary College, Westfield College, St Bartholomew's Hospital Medical College and the London Hospital Medical College.