Before 1960, the Bursa of Fabricius was known to be important for development of lymphocytes in chickens, but the analogous organ in mammals was unknown. At that time the thymus was generally thought to be an “evolutionary accident” of little consequence; merely a graveyard for lymphocytes. Now, the concept that T and B cells are distinct, and must collaborate for adaptive immune responses, is entrenched in textbooks, and underpins therapies to combat infection, organ rejection, autoimmune diseases, immune-deficiencies and cancer. The 2019 Albert Lasker Basic Medical Research Award recognises the ground-breaking discoveries made by Jacques Miller and Max Cooper who defined the anatomical origins of the two arms of adaptive immunity, the specialisation of T and B cells for host defence, and the nature of the collaboration between these cell types to mount effective immune responses. In the decades since these discoveries, T and B cell development has been a fertile ground for research in cell death and differentiation.

In 1960, it was known that the thymus was full of lymphocytes, but it was thought to be irrelevant to immunity because thymectomy of adult mice had no measurable impact. Jacques Miller, working in converted stables at the Institute of Cancer Research in the UK, mastered the surgical removal of the thymus from newborn mice in order to probe the nature of a virus-induced leukaemia. To his surprise, he found that neonatally thymectomized mice succumbed to fatal infections, were deficient in “small” lymphocytes, had impaired antibody production, and could not reject foreign skin grafts [1, 2]. He also discovered that thymic grafts from genetically distinct mice could not only restore immune function, but also engender tolerance to skin grafts from the donor origin [1, 3]. This stunning series of single author papers established the immunological function of the thymus and its role in distinguishing self from non-self.

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account
Continue with Google
Continue with ORCiD