Antibody Fucosylation Lowers the FcγRIIIa/CD16a Affinity by Limiting the Conformations Sampled by the N162-Glycan.
Antibody Fucosylation Lowers the FcγRIIIa/CD16a Affinity by Limiting the Conformations Sampled by the N162-Glycan.
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DOI：
10.1021/acschembio.8b00342
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发表时间：
2018-08-17
影响因子：
4
通讯作者：
Barb AW
中科院分区：
文献类型：
--
作者：
Falconer DJ;Subedi GP;Marcella AM;Barb AW
治疗性单克隆抗体（mAb）主要基于免疫球蛋白G1（IgG 1）支架，许多通过结合Fc γ受体引发细胞毒性细胞介导的应答。核心岩藻糖基化是IgG 1可结晶片段（Fc）上天冬酰胺（N）连接碳水化合物的一种普遍修饰，可降低Fc γ受体IIIa（CD 16 a）结合亲和力和mAb效力。我们确定，与无岩藻糖基化IgG 1 Fc相比，IgG 1 Fc岩藻糖基化使CD 16 a亲和力降低1.7 ± 0.1 kcal/mol，然而，CD 16 a N-聚糖截短使该罚分降低1.2 ± 0.1 kcal/mol或70%。Fc岩藻糖基化通过置换CD 1 - 6 a Asn 162-聚糖限制了多种构象采样，该聚糖影响α甘露糖（1-6）β甘露糖残基之间的连接并促进与IgG Tyr 296残基的接触。岩藻糖基化也影响IgG 1 Fc结构，如通过溶液NMR光谱观察到的共振频率和核自旋弛豫的变化所示。与无岩藻糖基化IgG 1 Fc相比，岩藻糖基化对IgG 1 Fc的影响可能是岩藻糖基化IgG 1 Fc结合CD 16 a的剩余0.5 ± 0.1 kcal/mol罚分的原因。我们的结果表明，CD 16 a Asn 162-聚糖通过减少采样体积间接调节抗体亲和力，而不是先前提出的分子间聚糖-聚糖接触的直接机制来稳定该系统。因此，增强分子间聚糖-聚糖接触的抗体工程可能提供有限的改善，未来的设计应通过维持CD 16 a Asn 162-聚糖构象异质性来最大化亲和力。
Therapeutic monoclonal antibodies (mAbs) are largely based on the immunoglobulin G1 (IgG1) scaffold and many elicit a cytotoxic cell-mediated response by binding Fc γ receptors. Core fucosylation, a prevalent modification to the asparagine(N)-linked carbohydrate on the IgG1 crystallizable fragment (Fc), reduces Fc γ receptor IIIa (CD16a) binding affinity and mAb efficacy. We determined IgG1 Fc fucosylation reduced CD16a affinity by 1.7 ± 0.1 kcal/mol when compared to afucosylated IgG1 Fc, however, CD16a N-glycan truncation decreased this penalty by 1.2 ± 0.1 kcal/mol or 70%. Fc fucosylation restricted the manifold of conformations sampled by displacing the CD16a Asn162-glycan which impinges upon the linkage between the αmannose(1-6)βmannose residues and promoted contacts with the IgG Tyr296 residue. Fucosylation also impacted IgG1 Fc structure as indicated by changes in resonance frequencies and nuclear spin relaxation observed by solution NMR spectroscopy. The effects of fucosylation on IgG1 Fc may account for the remaining 0.5 ± 0.1 kcal/mol penalty of fucosylated IgG1 Fc binding CD16a when compared to afucosylated IgG1 Fc. Our results indicated the CD16a Asn162-glycan modulates antibody affinity indirectly through reducing the volume sampled, as opposed to a direct mechanism with intermolecular glycan-glycan contacts previously proposed to stabilize this system. Thus, antibody engineering to enhance intermolecular glycan-glycan contacts will likely provide limited improvement and future designs should maximize affinity by maintaining CD16a Asn162-glycan conformational heterogeneity.
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DOI：
10.1073/pnas.80.21.6632
发表时间：
1983-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
NOSE, M;WIGZELL, H
通讯作者：
WIGZELL, H
DOI：
10.1107/s0907444909052925
发表时间：
2010-02
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Adams PD;Afonine PV;Bunkóczi G;Chen VB;Davis IW;Echols N;Headd JJ;Hung LW;Kapral GJ;Grosse-Kunstleve RW;McCoy AJ;Moriarty NW;Oeffner R;Read RJ;Richardson DC;Richardson JS;Terwilliger TC;Zwart PH
通讯作者：
Zwart PH
影响因子：
2.7
作者：
DELAGLIO, F;GRZESIEK, S;BAX, A
通讯作者：
BAX, A
影响因子：
20.3
作者：
Kapur, Rick;Kustiawan, Iwan;Vidarsson, Gestur
通讯作者：
Vidarsson, Gestur
DOI：
10.1107/s0907444911001314
发表时间：
2011-04
期刊：
Acta crystallographica. Section D, Biological crystallography
影响因子：
--
作者：
Murshudov GN;Skubák P;Lebedev AA;Pannu NS;Steiner RA;Nicholls RA;Winn MD;Long F;Vagin AA
通讯作者：
Vagin AA