Enteric nervous system injury and intestinal dysmotility after West Nile virus infection is mediated by perforin and Fas-ligand dependent T cell effector functions

Intestinal dysmotility syndromes have been linked to antecedent bacterial and viral infections. For example, infection of mice with the neurotropic flavivirus, West Nile Virus (WNV), leads to intestinal transit defects. Here, we find that within one week of WNV infection, enteric neurons and glia become damaged, resulting in a permanent reduction in their network density. Using cell-depleting antibodies, adoptive transfer experiments, and mice lacking specific immune cells or immune functions, we show that infiltrating WNV-specific CD4+ and CD8+ T cells damage the enteric nervous system (ENS) and glia, which leads to intestinal dysmotility; these T cells use multiple and redundant effector functions including perforin and Fas ligand. In comparison, WNV-triggered ENS injury and intestinal dysmotility occurs independently of infiltrating monocytes, whereas resident muscularis macrophages prevent excessive damage to the ENS and glia. Overall, our experiments establish that antigen specific T cell subsets and their effector molecules responding to WNV infection cause an immune pathology directed against neurons and supporting glia that results in intestinal dysmotility. Translating ribosomal affinity purification (TRAP) of the muscularis externa of West Nile virus (WNV) and mock-infected Snap25l10a GFP mice was performed at 6 days post infection to identify factors regulating response of enteric neurons in distal part of small intestine to WNV. Isolated immunopreciptated ribosome-bound mRNA from enteric neurons was used for high-throughput sequencing.