Function of novel human T cell subsets in host defence (360G-Wellcome-109965_Z_15_Z)

The immune response plays a critical role in host defence against pathogens, but it must be finely tuned in order to prevent harmful responses which can cause disease. This is particularly the case in the liver and gut, where there are harmless commensals and food present, but potentially also significant infectons such as hepatitis viruses B and C. We have uncovered groups of lymphocytes (T cells) which are highly abundant in human liver and gut and which have distinctive mechanisms for host de fence and fine tuning. In these studies we aim to understand how they are able to respond to viruses such as hepatitis viruses and how this function may alter dependent on where they are located. We also aim to understand how such mechanisms can be tuned to promote immunity to viruses and how T cells induced by new vaccines might be able to survive long term in such tissues and provide protection. Overall using a set of new tools designed to probe immunity in tissues in detail - we will define the functions of these specific protective cells in humans, and learn in particular how to modify their functions to improve host defence.