Determining the protective role of hepatic CD4 resident memory T-cells in Salmonella infection 3336

Abstract Description Systemic infections with non-typhoidal Salmonella serovars, such as Salmonella enterica Typhimurium (STm) are a leading cause of death in sub-Saharan Africa. Currently, there are moderately effective live vaccines, but they cannot be administered to immunocompromised individuals. Therefore, it is necessary to develop an effective sub-unit vaccine to improve public health in endemic areas. In a mouse model of infection, sub-unit vaccination using antigens recognized by circulating memory T cells provides modest protection, but not complete protection as conferred from a live vaccine with an attenuated STm strain. Previous research has shown the hepatic CD4 T resident memory (TRM) population is required for complete protection, but the recognized antigens remain unknown. To discover these antigens, we identified expanded hepatic TRM clonotypes using single-cell RNA sequencing on cells from Salmonella-infected mice. Top clonotype T cell receptors (TCRs) were retrovirally transduced into TCR-deficient murine CD4 T cell hybridomas. The hybridomas were then incubated with antigen-presenting cells (APCs) and a Salmonella shotgun genomic E. coli library to screen for activation from cognate antigen presentation via IL-2 secretion. Bacteria from positive wells were sequenced to identify the expressed Salmonella protein. In the future, the newly identified antigens will be administered as a sub-unit vaccine and evaluated for levels of conferred protection against primary STm infection. Funding Sources Supported by: R01AI139410 Target Antigen Identification to Improve Salmonella Vaccination; Animal Models of Infectious Disease T32; Floyd and Mary Schwall Dissertation Year Fellowship in Medical Research Topic Categories Microbial, Parasitic, and Fungal Immunology (MPF)