Final Activity Report Summary - T-CELLS AND SHIGELLA (T-cell immune response and T-cell apoptosis in Shigella infection)
Shigellosis is an acute infection of the human colon causing dysentery characterised by pain, fever, and severe bloody diarrhoea. The burden of this disease is estimated to 150 million cases and 1 million deaths per year. No efficient shigella vaccine is currently available. Protective immunity is conferred by a humoral response, however the cellular response and its contribution to protection remains elusive. We, therefore, investigated the shigella-induced T cell immunity using a murine model of infection and found that s. flexneri strongly induces IL-17 producing CD4+. IL-17 producing CD4+ cells (Th17) were very recently described as a separate lineage; nevertheless their function in protective immunity against pathogens was poorly defined. Shigella-specific Th17 could be found up to seven months after the clearance of infection indicating that these CD4+ cell subtype could acquire a memory-phenotype. Finally, our experiments revealed that IL-17 had an important function in the clearance of a primary and, more importantly, secondary infection. These results would contribute to the improvement of rational design of new vaccine strategies.