アフコシル化抗体の生産のため、CHOK1-Fut8KO発現プラットフォームを新たに立ち上げました。当社のハイスループット・リコンビナント抗体発現プラットフォームと細胞培養技術との組み合わせ、研究および産業上のニーズに合わせてアフコシル化抗体を迅速に生産することができます。アフコシル化は、antibody-dependent cell-mediated cytotoxicity (ADCC)を著しく高めることが示されており、有効性を高めることにより標的療法の可能性を広げます。
ノックアウトされたFut8細胞株は、アフコシル化抗体の生産に適用されています。 Fut8は、α-1,6フコシルグリコシド結合の形成を触媒する酵素であり、したがって、アスパラギン酸に結合したN-アセチルグルコサミン部位へのフコースの付加を行います。1
フコースフリー宿主細胞CHOK1BN-Fut8KOは、抗体の特性評価と機能検証を行った後、工業生産に使用することができます。一般的なCHOK1BN細胞株と比較して、CHOK1BN-Fut8KOによって産生された抗体は、アフコシル化が達成されるだけでなく、発現量と品質の面でも一貫性が保たれます。
Afucosylation has been demonstrated to increase the effectiveness of antibody-dependent cellular cytotoxicity (ADCC). ADCC is regulated by N-linked glycosylation in the Fc region of the antibody.
Importantly, in therapeutic antibodies such as CD20, Her2, and EGFR, absence of core fucose on the Fc N-glycan enhances IgG1 Fc binding affinity to FcγRIIIa on immune effector cells such as natural killer cells. This results in increased ADCC activity, and thus can improve therapeutic efficacy.2
Chinese hamster ovary (CHO) cell lines are derived from the ovary of adult, female Chinese hamsters. CHO cells were first established in 1957 by T. Puck, and were subsequently multiplied and optimized in vitro, allowing it to be cultured indefinitely. The CHO-K1 cell line was derived as a subclone from that parental CHO cell line. They are typically the preferred host expression system for recombinant antibodies due to their advantages in producing complex therapeutics, manufacturing adaptability, and glycosylation features similar to human IgG.3
However, the Fc domain of the anti-tumor antibody drugs produced by wild-type CHO cells carries fucose sugar residues on both of its two biantennary complex polysaccharide chains. The presence of fucose residues can hinder the binding between the antibody and Fc receptor, thereby affecting the antibody's ADCC activity and anti-cancer efficacy.
Although YB2/0 hybridoma cells and plant cells can be used as alternatives to CHO cells for producing antibody molecules, they lack the stability and scalability advantages of CHO cells.
ADCC causes the natural killer (NK) cells to release cytokines and cytolytic agents, eventually killing the target cell. This is triggered by the engagement of immune complexes with FcγRIIIa present on NK cells, when the Fc binds with the Fc-γ receptor. This binding is significantly influenced by N-glycans in the CH2 structural domain.2
Afucosylated antibodies are monoclonal antibodies which have been modified. The N-glycan (oligosaccharide and sialylation) residues in the antibody’s Fc region do not have core fucose sugar units, which can increase the effector function of ADCC.
Several factors, including cell line characteristics, process control parameters, and cell culture medium components, may affect glycosylation and, consequently, biological activity, efficacy, stability, immunogenicity, clearance rate, and ADCC.2