Murine norovirus inhibits B cell development in the bone marrow of STAT1-deficient mice.

Noroviruses are a leading cause of gastroenteritis in humans and it was recently revealed that noroviruses can infect B cells. We demonstrate that murine norovirus (MNV) infection can significantly impair B cell development in the bone marrow in a signal transducer and activator of transcription 1 (STAT1) dependent, but interferon signaling independent manner. We also show that MNV replication is more pronounced in the absence of STAT1 in ex vivo cultured B cells. Interestingly, using bone marrow transplantation studies, we found that impaired B cell development requires Stat1 hematopoietic cells and Stat1 stromal cells, and that the presence of wild-type hematopoietic or stromal cells was sufficient to restore normal development of Stat1 B cells. These results suggest that B cells normally restrain norovirus replication in a cell autonomous manner, and that wild-type STAT1 is required to protect B cell development during infection.