(585h) Proteomics: Mechanism of Biosimilar Quality Regulation in Three CHO Host Cells

The interest in developing “biosimilars” (generic or follow-on versions of biologics) has been increased with the patents expiration of many biologics. However, this development effort requires a comprehensive understanding of mammalian cell based protein expression and production. The construction of a high-yield protein producing cell line is time-consuming work, so the choice of an appropriate protein expression system based on the requirements of the characteristics and the timeframe of the expressed products is critical in biopharmaceutical industry. In this study, three CHO cells (i.e. CHO K1, CHO DG44, CHO S) were investigated to evaluate the effect of host cell regulation on therapeutic protein expression and quality control. First, appropriate chemical defined media (CD CHO, CD FortiCHO and CD M4CHO) were applied to cultivate the suspension culture of these three CHO cells. Second, the global proteomics profiling of host cells, especially the enzymes in glycosylation and sialylation pathways, were analyzed using Proteomics analysis. Third, both GS and dhfr- expression vectors were used to construct biosimilar IgG 1 expression cell lines. The comparison of protein glycosylation by different host cell in different production media could provide us a direction in the development of biosimilar expression and production. With the developed fundamental understanding of host cell regulation of protein glycosylation, it is feasible to rationally design a robust engineered CHO host cell in future.