Distinct roles of interferon alpha and beta in controlling chikungunya virus replication and modulating neutrophil-mediated inflammation

Lindsey E. Cook, Washington University School of Medicine in St. Louis
Marissa C. Locke, Washington University School of Medicine in St. Louis
Alissa R. Young, Washington University School of Medicine in St. Louis
Kristen Monte, Washington University School of Medicine in St. Louis
Matthew L. Hedberg, Washington University School of Medicine in St. Louis
Raeann M. Shimak, Washington University School of Medicine in St. Louis
Kathleen C.F. Sheehan, Washington University School of Medicine in St. Louis
Deborah J. Veis, Washington University School of Medicine in St. Louis
Michael S. Diamond, Washington University School of Medicine in St. Louis
Deborah J. Lenschow, Washington University School of Medicine in St. Louis

Abstract

Type I interferons (IFNs) are key mediators of the innate immune response. Although members of this family of cytokines signal through a single shared receptor, biochemical and functional variation exists in response to different IFN subtypes. While previous work has demonstrated that type I IFNs are essential to control infection by chikungunya virus (CHIKV), a globally emerging alphavirus, the contributions of individual IFN subtypes remain undefined. To address this question, we evaluated CHIKV pathogenesis in mice lacking IFN-β (IFN-β knockout [IFN-β-KO] mice or mice treated with an IFN-β-blocking antibody) or IFN-α (IFN regulatory factor 7 knockout [IRF7-KO] mice or mice treated with a pan-IFN-α-blocking antibody). Mice lacking either IFN-α or IFN-β developed severe clinical disease following infection with CHIKV, with a marked increase in foot swelling compared to wild-type mice. Virological analysis revealed that mice lacking IFN-α sustained elevated infection in the infected ankle and in distant tissues. In contrast, IFN-β-KO mice displayed minimal differences in viral burdens within the ankle or at distal sites and instead had an altered cellular immune response. Mice lacking IFN-β had increased neutrophil infiltration into musculoskeletal tissues, and depletion of neutrophils in IFN-β-KO but not IRF7-KO mice mitigated musculoskeletal disease caused by CHIKV. Our findings suggest disparate roles for the IFN subtypes during CHIKV infection, with IFN-α limiting early viral replication and dissemination and IFN-β modulating neutrophil-mediated inflammation.