Preparation and Biological Evaluation of a Glycosylated Fusion Interferon Directed to Hepatic Receptors

Abstract

The antiviral activity and biodistribution of a glycosylated fusion interferon directed to hepatic receptors were evaluated to determine whether its pharmaceutical concentration in the liver could be improved. The novel glycosylated fusion interferon, galactosyl-human serum albumin-interferon-alpha2b (G-HSA-IFN) was obtained from a long-term recombinant fusion protein (HSA-IFN) by covalent coupling with a bifunctional reagent, 2-imino-2-ethyloxymethy1-1-thiogalactose. There are about 24 thiogalactose residues in each G-HSA-IFN molecular on average. The antiviral activities of IFNalpha2b, HSA-IFN, and G-HSA-IFN were compared in a cytopathic effect inhibition assay with the WISH/VSV system in vitro, and the modification had little effect on its antiviral activity. Both G-HSA-IFN and HSA-IFN were labeled with 125I and the radiochemical purity of 125I-G-HSA-IFN was greater than 96%. 125I-G-HSA-IFN bound to the asialoglycoprotein receptor (ASGP-R) on hepatic cells much more specifically than 125I-HSA-IFN, with specific binding rates of 89.53% and 6.66%, respectively (p < 0.01). Biodistribution research in mice showed that 125I-G-HSA-IFN could concentrate effectively in the liver (>45%/g) and suggested that it also could be a good imaging agent of hepatic receptors.