Structure-based glycoengineering of interferon lambda 4 enhances its productivity and anti-viral potency

Abstract

Interferon lambda 4 (IFN lambda 4) has been recently known and studied for its role in hepatitis C virus (HCV) infection, but its clinical potential is significantly hampered due to its poor expression in vitro. Our study reports the successful production of IFN lambda 4 from a mammalian cell line through a glycoengineering and structure-based approach. We introduced de novo N-glycosylation of IFN lambda 4, guided by structural analysis, and produced IFN lambda 4 variants in Expi293F that displayed improved expression and potency. To preserve the structure and functionality of IFN lambda 4, the model structure of the IFN lambda 4 signaling complex was analyzed and the N-glycosylation candidate sites were selected. The receptor binding activity of engineered IFN lambda 4 variants and their receptor-mediated signaling pathway were similar to the E. coli version of IFNM (eIFN lambda 4), while the antiviral activity and induction levels of interferon-stimulated gene (ISG) were all more robust in our variants. Our engineered IFN lambda 4 variants may be further developed for clinical applications and utilized in basic research to decipher the immunological roles of IFN lambda 4.