Th165 - Single-cell Analysis of Thymic Dysregulation and Viral Tropism After Neonatal Roseolovirus Infection

Andrei Belean – Internal Medicine – Washington University in St. Louis; Ben Cisneros – Pediatrics – Washington University in St. Louis; Eden Xue – Pediatrics – Washington University in St. Louis; Eli Roberson – Internal Medicine – Washington University in St. Louis; Michael Paley – Internal Medicine – Washington University in St. Louis

Abstract Text: Herpesviruses, including the roseoloviruses, have been linked to autoimmune disease. The ubiquitous, chronic nature of herpesvirus infections in which acute infection occurs years before onset of autoimmune disease onset makes establishing a causal association challenging. We showed that murine roseolovirus (MRV), which is highly related to human roseoloviruses, induced disruption of central tolerance after neonatal infection, resulting in development of autoimmunity in adult mice, long after resolution of acute infection. This suggested that MRV induces durable immune dysregulation. In these studies, we utilized single-cell RNA sequencing to identify the tropism of MRV in the thymus and determine cellular processes that were disrupted by neonatal MRV infection. We found that MRV infection resulted in major shifts in inflammatory, differentiation and cell cycle pathways in infected thymocytes. We identified the cellular tropism of MRV in the thymus to include double negative, double positive, and CD4 single positive thymocytes, as well as medullary thymic epithelial cells. We also establish the inflammatory response to thymic infection, which was characterized by a type I IFN as well as an IL-36 response. We identified transcriptional changes that suggested disruption of interactions between antigen presenting cells and thymocytes that could alter survival and selection. Our results provide the first complete picture of roseolovirus tropism and roseolovirus-induced transcriptomic disruption in the thymus after neonatal infection. These studies define how MRV alters the microenvironment of the thymus after neonatal MRV infection, providing insight into how roseoloviruses disrupt central tolerance and promote development of autoimmune disease.