人干扰素α2b和IgG Fc片段融合蛋白显著延长体内半衰期

Enhanced Circulation Half-life for Human IFNα2b and IgG Fc Fusion Protein

摘要:

重组人干扰素α(rHuIFNα)已被广泛用于临床治疗多种人类病毒性疾病和肿瘤。但IFNα在体内半衰期较短从而导致IFNα在用药后数小时即从血浆中被清除。目前常用化学修饰和构建融合蛋白的方法来延长IFNα的半衰期。在本研究中, 构建了IFNα2b与人IgG免疫球蛋白Fc片段的融合基因(IFNα2b-Fcγ)并在毕赤酵母中以二聚体形式分泌表达, 并有部分糖基化。不同亚型Fcγ片段的融合蛋白对IFNα2b抗病毒活性均有一定影响。其中IFNα2b-Fcγ2所受影响最小, 较单纯的IFNα2b降低了2.3倍, 抗病毒活性可达4.29x107 IU/mg, 大鼠皮下注射后循环血液中半衰期达65 h, 血液中存留时间120 h以上, 比商品重组干扰素的体内半衰期延长约8倍, 血液存留时间延长10倍, 显示了其良好的临床应用 前景。

Abstract:

Recombinant human interferon alpha (rHuIFNα) has been successfully used in antiviral and antitumor treatment. However, it degrades rapidly in vivo, resulting in the disappearance of cytokine in the plasma within several hours after administration. Strategies including chemical modification and fusion proteins have been used to improve the half-life of IFNα in vivo. In the present study, we constructed fusion proteins with IFNα2b and the IgG Fc region from various subtypes of human IgG and expressed them in methylotropic yeast, Pichia pastries. The fusion proteins were secreted to the culture medium as the active form of disulfide-linked homodimer with a single glycoslation modification on each molecule. Regardless of the subtype of Fcγ, fusing Fcγ fragments to IFNα2b showed impaired antiviral activities than the control IFNa2b in vitro. With the highest antiviral activity, IFNα2b-Fcγ2 was measured as 4.29×107 IU/mg, which decreased 2.3 times compared to the control IFNa2b. The half-life of IFNα2b-Fcγ2 in blood circulation extended to 65 hours and was still detectable until 120 hours, which was 8 times longer for circulation half-life and 10 times longer for metabolic kinetic time than the control IFNα2b. The results demonstrated that fusing IgG Fc region with IFNα2b could improve the pharmacokinetic properties of the fusion proteins, which has the potential in clinical therapy.