Comparison of adaptive immunity between different Salmonella serovers

Project Summary/Abstract Systemic Salmonella infections have three main infectious causes (Typhi, Paratyphi, and a group of non- typhoidal serovars). Although new conjugate vaccines exist for Typhi, there are still no licensed vaccines for Paratyphi or non-typhoidal disease, despite the fact that they account for more than 50% of deaths due to systemic Salmonellosis. Since Typhi and Paratyphi serovars do not infect other animals, most of what we know about adaptive immunity to Salmonella comes from infection of mouse strains with NTS strains. In this application we will use a new mouse model that is permissive for Typhi infection and allows side-by-side analysis of typhoidal and non-typhoidal disease. We propose to, (i) validate this new model by testing whether typhoid strains have delayed T cell and B cell activation in vivo, and (ii) determine whether ViCPS expression allows evasion of adaptive immunity.