Abstract
The role of mesenchymal stromal cells (MSCs) in regulating immune responses in the thymus is currently unclear. Here we report the existence and role of a MSC population in the thymus that expresses the pericyte and MSC marker CD248 (endosialin). We show using a CD248‐deficient mouse model, that CD248 expression on these cells is required for full post‐natal thymus development and regeneration post‐Salmonella infection. In CD248−/− mice the thymus is hypocellular and regeneration is poorer, with significant loss of all thymocyte populations. This identifies the requirement of CD248 to maintain optimal thymic cellularity post‐partum and infection.