Inhibition of Sialidase Activity for Enhanced Sialylation of Albumin-erythropoietin in Biphasic CHO Cell Cultures

초록

Terminal sialic acid residues of N-linked glycan have a profound impact on the half-life of glycoproteins as they prevent the recognition by asialo-glycoprotein receptor. It is important to maximize sialic acid contents of glycoprotein to increase half-life. Desialylation of recombinant glycoproteins during cell culture is known to be caused by the release of intracellular sialidase by cell lysis. In this study, biphasic culture of recombinant Chinese hamster ovary cells producing albumin-erythropoietin was investigated to enhance sialylation. Biphasic cultures were performed with different concentrations of CO2 and temperatures. Raising CO2 concentration from 1% to 15% acidified the medium. Culture conditions was changed on day 5, when viable cell density was decreased and sialidase was started to be released by cell lysis. At the lowest CO2 concentration, sialidase activity was declined. However, culture temperature was not significant in affecting sialidase activity compared with CO2 concentration. As a result, sialidase activity was the lowest when the culture was shifted from normal culture condition to 1% CO2 and 33℃ on day 5. In conclusion, this biphasic cultivation method was found to improve the sialylation of recombinant glycoproteins.