Myeloid Cells Restrict MCMV and Drive Stress- Induced Extramedullary Hematopoiesis through STAT1

Cytomegalovirus (CMV) has a high prevalence worldwide, is often fatal for immunocompromised patients, and causes bone marrow suppression. Deficiency of signal transducer and activator of transcription 1 (STAT1) results in severely impaired antiviral immunity. We have used cell- type restricted deletion of Stat1 to determine the importance of myeloid cell activity for the defense against murine CMV (MCMV). We show that myeloid STAT1 limits MCMV burden and infection- associated pathology in the spleen but does not affect ultimate clearance of infection. Unexpectedly, we found an essential role of myeloid STAT1 in the induction of extramedullary hematopoiesis (EMH). The EMH- promoting function…