Salmonella SPI-2 type III secretion system-dependent inhibition of antigen presentation and T cell function

•Salmonella has evolved mechanisms that interfere with T cell activation.•Salmonella delays contact between dendritic cells and T cells.•Antigen presentation to T cells is inhibited in Salmonella-infected dendritic cells.•Infection of mice by Salmonella leads to culling and delayed activation of T cells. Salmonella enterica serovars infect a broad range of mammalian hosts, including humans, causing both gastrointestinal and systemic diseases. Effective immune responses to Salmonella infections depend largely on CD4+ T cell activation by dendritic cells (DCs). Bacteria are internalised by intestinal DCs and respond by translocating effectors of the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (T3SS) into host cells. In this review, we discuss processes that are hijacked by SPI-2 T3SS effectors and how this affects DC biology and the activation of T cell responses.