Interferon alpha (IFNα) conjugated with polyethylene glycol (PEG) has been widely used for the treatment of hepatitis C virus (HCV) infection as a once-a-week injection formulation. However, the PEGylated IFNα has a low efficacy of ca. 39% and a side effect after repeated injections possibly due to the non-specific delivery with PEGylation. In this work, target specific long-acting hyaluronic acid-interferon alpha (HA-IFNα) conjugate was successfully developed for the treatment of HCV infection. HA-IFNα conjugate was synthesized by coupling reaction between aldehyde modified HA and the N-terminal group of IFNα. The IFNα content could be controlled in the range of 2-9 molecules per single HA chain with a bioconjugation efficiency higher than 95%. According to in vitro anti-proliferation assay using Daudi cells, HA-IFNα conjugate showed a comparable biological activity to PEG-Intron. In vivo real-time bioimaging confirmed the target specific delivery of near-infrared fluorescence (NIRF) dye labeled HA-IFNα conjugate to the liver in mice. In addition, pharmacokinetic analysis revealed the enhanced residence time longer than 4 days. After tail-vein injection, HA-IFNα conjugate induced ca. 60% higher expression of 2',5'-oligoadenylate synthetase 1 (OAS 1) for innate immune responses to viral infection in the murine liver tissues than IFNα and PEG-Intron.
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