Mx1 in Hematopoietic Cells Protects against Thogoto Virus Infection.

() is an interferon-induced gene that encodes a GTPase that plays an important role in the defense of mammalian cells against influenza A and other viruses. The Mx1 protein can restrict a number of viruses independently of the expression of other interferon-induced genes. genes are therefore considered to be an important part of the innate antiviral immune response. However, the possible impact of expression in the hematopoietic cellular compartment has not been investigated in detail in the course of a viral infection. To address this, we performed bone marrow chimera experiments using congenic B6.A2G and B6.A2G mice to study the effect of expression in cells of hematopoietic versus nonhematopoietic origin. mice were protected and mice were susceptible to influenza A virus challenge infection, regardless of the type of bone marrow cells ( or ) the animals had received. Infection with Thogoto virus, however, revealed that mice with a functional gene in the bone marrow compartment showed reduced liver pathology compared with mice that had been grafted with bone marrow. The reduced pathology in these mice was associated with a reduction in Thogoto virus titers in the spleen, lung, and serum. Moreover, mice with bone marrow failed to control Thogoto virus replication in the spleen. in the hematopoietic cellular compartment thus contributes to protection against Thogoto virus infection. Mx proteins are evolutionarily conserved in vertebrates and can restrict a wide range of viruses in a cell-autonomous way. The contribution to antiviral defense of Mx1 expression in hematopoietic cells remains largely unknown. We show that protection against influenza virus infection requires expression in the nonhematopoietic cellular compartment. In contrast, in bone marrow-derived cells is sufficient to control disease and virus replication following infection with a Thogoto virus. This indicates that, in addition to its well-established antiviral activity in nonhematopoietic cells, Mx1 in hematopoietic cells can also play an important antiviral function. In addition, cells of hematopoietic origin that lack a functional gene contribute to Thogoto virus dissemination and associated disease.