The Contribution of Pulmonary Dendritic Cells to the Induction and Regulation of T Cell Responses During Respiratory Infection

Abstract The respiratory tract represents a major portal of entry for pathogens, including Group A Streptococci (GAS). GAS represents a significant burden in cases of primary infection as well as cases of secondary bacterial pneumonia following influenza virus infection. Control of infection and eventual resolution is dependent on the local adaptive immune response. This is facilitated by the uptake and subsequent presentation of antigen by dendritic cells (DC) to T cells. Furthermore, after GAS infection, DC drive T cell development towards a Th17 immune response that is associated with pathogen control. Our hypothesis is that pulmonary DC, both resident and recruited, contribute locally to the maintenance and regulation of an effector CD4 T cell response in the context of a GAS infection. Toward this end, our studies are defining the contribution of local DC: T cell interactions in shaping the phenotype and magnitude of Th17 and Tfh responses within the lungs during GAS infection. An improved understanding of the contribution of these DC to the development and regulation of these CD4 T cells responses during GAS infection should elaborate strategies to the development of better therapies.