This research project will test how the production of a molecule called nicotinamide adenine dinucleotide (NAD) is linked to T cell metabolism and both their protective and harmful activity. NAD is produced from vitamin B3 and is required for all stages of the breakdown of sugar and other nutrients in cells. The research group have already identified that when T cells are activated, or switched on, in the laboratory, they turn on enzymes which make NAD from vitamin B3. Additionally, when these enzymes are not active, T cells have much lower rates of metabolism and produce fewer immune signals.