Abstract: The differences of glycosylation between Pichia pastoris and human caused the side effects though the fusion protein of Interferon and albumin expressed in Pichia pastoris avoiding the defects of short half-life of monomer.At present,the drug expressed in CHO system has been widely used.The CHO cell line expressing the interferon alpha 2b and human serum albumin fusion protein(IFNα2b-HSA) was constructed for the first time in our lab.On this basis,chose 12 kinds of home-grown commercial basic serum free medium and 5 kinds of feeding medium to screening the most suitable combination.The most suitable training program is:the No.5 basic serum free medium(M2:M4=1:1) is most suitable for cell growth,the F4 feeding medium is most suitable for the protein expression.And then enlarge fermentation on 5L bioreactor,the parameters are as follows:pH6.9-7.4,DO60%-80%,cool the temperature from 37℃ down to 34℃ when the cell density up to 7.0×10⁶ cells/mL,stop fermentation when the cell survival rate down to 80%.The final expression of fusion protein reached 137mg/L.The high density fermentation of IFNα2b-HSA fusion protein in CHO cells was preliminarily realized.

Key words: interferon α2b, serum albumin, Chinese hamster ovary cell

摘要： 毕赤酵母表达的干扰素与白蛋白融合蛋白虽然避开了干扰素单体半衰期短的缺陷，但毕赤酵母对药物的糖基化修饰与人体的糖基化修饰差异性导致了药物的毒副作用。目前药物在CHO系统的表达得到了广泛应用。本研究室首次构建了能表达干扰素α2b和人血清白蛋白融合蛋白（IFNα2b-HSA）的CHO细胞株。在此基础上，本研究通过对12种国产商业化基础无血清培养基和5种流加培养基进行优化筛选，获得最适培养方案：基础培养基选择最适于生长的5号培养基（M2：M4=1：1），流加培养基选择最有适于表达的F4培养基。在此基础上，进行5L生物反应器的发酵放大，pH为6.9～7.4，DO为40%～60%，细胞密度达到7.0×10⁶cells/mL时，温度由37℃降温至34℃，细胞活率降至80%时停止发酵，最终融合蛋白表达量达到137mg/L。初步实现了IFNα2b-HSA融合蛋白在CHO细胞中的高密度发酵。

关键词: 干扰素α2b, 白蛋白, CHO细胞