Vaccination is the most successful and cost-effective means of combating infectious diseases in both veterinary and human medicine. There remain however many infectious diseases for which no vaccines exist or where vaccines have unacceptable side-effects. Most vaccines need an immunopotentiator or adjuvant to generate an effective immune response. The important role of adjuvants in directing the immune response has recently been recognised. This project aims to better characterise the action of a new generation of vaccine adjuvants and to identify critical pathways in immune stimulation. The results of these studies will facilitate the rational development of new vaccines and help reduce side-effects of vaccination.