Sialylation, which is considered as a critical quality attribute, plays important roles in pharmacokinetics of recombinant proteins. Terminal sialic acids of glycoproteins are modulated by intracellular sialyltransferase (ST) and extracellular sialidase. Since CHO cells producing recombinant proteins can only transfer α2,3-sialic acid to a nascent oligosaccharide, inactivation of α2,6-ST results in a different composition of glycan with human proteins, which have predominantly α2,6-linkages. To overcome this problem and maximize total sialic acid contents, we used glucocorticoids (GCs) that are classified as a steroid hormone in CHO cells expressing both α2,3-ST and α2,6-ST. This study was performed to determine the effect of GCs on CHO cell cultures and sialylation of Fc-fusion protein. We observed that all cultures supplemented with GCs reduced the titer of the Fc-fusion protein, but enhanced the sialylation level, when compared to those of control. Especially, addition of corticosterone increases the levels of α2,6-sialylation as well as the total contents of sialic acid. Enhanced sialic acid contents are thought to be due to the intracellular improvement by sialylatransferase and the inhibition of sialidase. In conclusion, GCs can be utilized as an effective medium additive to improve the quality of biopharmaceuticals using CHO cell cultures.

唾液酸化被认为是关键的质量属性，在重组蛋白的药代动力学中起重要作用。糖蛋白的末端唾液酸受细胞内唾液酸转移酶（ST）和细胞外唾液酸酶的调节。由于产生重组蛋白的CHO细胞只能将α2,3-唾液酸转移至新生的低聚糖，α2,6-ST的失活导致聚糖与人蛋白的成分不同，后者主要具有α2,6-键。为了克服这个问题并最大化唾液酸的总含量，我们在表达α2,3-ST和α2,6-ST的CHO细胞中使用了糖皮质激素（GCs），该糖皮质激素被分类为类固醇激素。进行这项研究是为了确定GC对CHO细胞培养和Fc融合蛋白唾液酸化的影响。我们观察到，与对照相比，所有添加了GC的培养物均降低了Fc融合蛋白的滴度，但增加了唾液酸化水平。特别地，添加皮质酮增加了α2，6-唾液酸化的水平以及唾液酸的总含量。唾液酸含量的增加被认为归因于唾液酸转移酶对细胞内的改善和唾液酸酶的抑制。总之，GC可以用作有效的培养基添加剂，以使用CHO细胞培养来提高生物制药的质量。唾液酸含量的增加被认为归因于唾液酸转移酶对细胞内的改善和唾液酸酶的抑制。总之，GC可以用作有效的培养基添加剂，以使用CHO细胞培养来提高生物制药的质量。唾液酸含量的增加被认为归因于唾液酸转移酶对细胞内的改善和唾液酸酶的抑制。总之，GC可以用作有效的培养基添加剂，以使用CHO细胞培养来提高生物制药的质量。