NON-CANONICAL MECHANISMS FOR INTERFERON-LAMBDA REGULATION OF SARS-COV-2 INFECTION

PROJECT SUMMARY As the SARS-CoV-2 pandemic continues, a better understanding of the factors that regulate broadly protective immunity is needed. Interferon-lambda (IFN-λ) mediates antiviral protection against SARS-CoV-2 without causing overt pathology and exacerbated disease. As such, recombinant IFN-λ is in clinical trials as a therapeutic for COVID-19. However, the endogenous role for IFN-λ in regulating infection and functions in preventing disease beyond antiviral programming during SARS-CoV-2 remain unknown. Our preliminary data show that mice lacking the IFN-λ receptor (Ifnlr1-/-) have increased illness and viral burden during SARS-CoV-2 infection without alteration of canonical antiviral gene induction associated with IFN. Instead, IFN-λ positively regulates the induction of CD8 T cell immunity, a cellular immune response critical to mediating protection against virus infection when neutralizing antibody responses are avoided. We further identified upregulation of cell cycle repair and proliferation genes associated with fibrosis in Ifnlr1-/- mice. This proposal will investigate these newly identified non-canonical functions of IFN-λ in regulating immunity against SARS-CoV-2 with the goal of informing therapeutic use of this cytokine.