Modulation of innate immune responses by hantaviruses.

Hantavirus infection can cause hantavirus cardiopulmonary syndrome or hemorrhagic fever with renal syndrome depending on the virus species involved. The determinants for the virus species specific virulence in humans are unclear. Successful infection is a conditio sine qua non for the virulence of a virus and it is well-known that the innate interferon (IFN) system generally plays a decisive role to prevent establishment of an infection. The importance of the IFN system is underscored by the fact that viruses have developed an amazing number of different escape mechanisms to enable replication in face of the antiviral host response. Interestingly, pathogenic hantaviruses escape induction of innate antiviral responses in the early phase of the infection, which are elicited in a pronounced manner by nonpathogenic hantaviruses in vitro. This differential response might be important for the pathogenicity of hantaviruses in humans. This review aims to summarize the current knowledge about the interaction between hantaviruses and the innate IFN system. Detailed characterization of the cellular sensors and pathways that lead to activation of the IFN system on one side and the viral escape mechanisms on the other might help to develop novel vaccination strategies and therapeutic approaches.