Don Mason (immunologist)

Donald W. "Don" Mason is a British immunologist and former professor of immunology in the MRC Cellular Immunology Unit at the Sir William Dunn School of Pathology at the University of Oxford. Professor Mason is best known for his work on regulatory T cells and their role in preventing autoimmunity.

Although Mason began life as a physicist studying nuclear fusion, he is best known for his work on cellular immunology. He carried out studies at Oxford University into multiple sclerosis. Mason's most important contributions to immunology are his studies defining the existence, cell surface phenotype and function of regulatory T cells. Mason's studies identified the immuno-regulatory capacity of a population of CD4+ T cells which expressed low levels of OX22 (an isoform of CD45: CD45RC in rats and CD45RB in mice) and their capacity to prevent the pathogenic activity of the OX22hi subset. His work focused mainly on the role of Tregs in the prevention of diabetes and thyroiditis and highlighted the role for the thymus in the development of Tregs,. These were among the earliest demonstrations of the requirement for Treg in restraining the pathogenic activity of CD4+ T cells and prevention of autoimmunity. Prof. Mason retired from research in 1999 and still lives in the Oxford area.