The weaker-binding Fc γ receptor IIIa F158 allotype retains sensitivity to N-glycan composition and exhibits a destabilized antibody-binding interface.
The weaker-binding Fc γ receptor IIIa F158 allotype retains sensitivity to N-glycan composition and exhibits a destabilized antibody-binding interface.
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DOI：
10.1016/j.jbc.2022.102329
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发表时间：
2022-09
影响因子：
4.8
通讯作者：
Barb, Adam W.
中科院分区：
文献类型：
--
作者：
Kremer, Paul G.;Barb, Adam W.
抗体与Fc γ受体（Fcγ R）结合，在与靶抗原结合后引发愈合细胞免疫应答。Fc γ受体IIIa/CD 16 a触发自然杀伤细胞以细胞毒性蛋白破坏靶组织，并增强巨噬细胞介导的吞噬作用。多种变量影响CD 16 a抗体结合强度和产生的免疫应答，包括遗传多态性。主要的CD 16 a F158同种异型以比不太常见的V158同种异型低的亲和力结合抗体。这种多态性同样影响依赖于CD 16 a接合的抗体的细胞免疫应答和临床功效，尽管V/F158如何影响CD 16 a结构仍不清楚。显示影响亲和力的另一个相关变量是CD 16 a天冬酰胺连接的（N）-聚糖的组成。目前尚不清楚N-聚糖组成如何影响CD 16 a F158亲和力。在这里，我们确定N-聚糖组成对V158和F158同种异型的影响相似，并且N-聚糖组成不能解释V158和F158结合亲和力的差异。我们的结合动力学分析表明N162聚糖减慢了结合事件，缩短N-聚糖或去除N162聚糖增加了结合速度。F158显示比V158更慢的结合速率。令人惊讶的是，我们发现N-聚糖组成对解离速率的影响较小。我们还使用NMR光谱鉴定了CD 16 a F158骨架酰胺和N162聚糖共振的构象异质性。在V158和F158之间表现出化学位移扰动的残基映射到抗体结合界面。这些数据支持CD 16 a F158的模型，该模型具有增加的界面构象异质性，减少了可用的结合活性形式的群体并降低了亲和力。
Antibodies engage Fc γ receptors (FcγRs) to elicit healing cellular immune responses following binding to a target antigen. Fc γ receptor IIIa/CD16a triggers natural killer cells to destroy target tissues with cytotoxic proteins and enhances phagocytosis mediated by macrophages. Multiple variables affect CD16a antibody-binding strength and the resulting immune response, including a genetic polymorphism. The predominant CD16a F158 allotype binds antibodies with less affinity than the less common V158 allotype. This polymorphism likewise affects cellular immune responses and clinical efficacy of antibodies relying on CD16a engagement, though it remains unclear how V/F158 affects CD16a structure. Another relevant variable shown to affect affinity is composition of the CD16a asparagine-linked (N)-glycans. It is currently not known how N-glycan composition affects CD16a F158 affinity. Here, we determined N-glycan composition affects the V158 and F158 allotypes similarly, and N-glycan composition does not explain differences in V158 and F158 binding affinity. Our analysis of binding kinetics indicated the N162 glycan slows the binding event, and shortening the N-glycans or removing the N162 glycan increased the speed of binding. F158 displayed a slower binding rate than V158. Surprisingly, we found N-glycan composition had a smaller effect on the dissociation rate. We also identified conformational heterogeneity of CD16a F158 backbone amide and N162 glycan resonances using NMR spectroscopy. Residues exhibiting chemical shift perturbations between V158 and F158 mapped to the antibody-binding interface. These data support a model for CD16a F158 with increased interface conformational heterogeneity, reducing the population of binding-competent forms available and decreasing affinity.
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影响因子：
4
作者：
Falconer DJ;Subedi GP;Marcella AM;Barb AW
通讯作者：
Barb AW
影响因子：
4.6
作者：
Sakae Y;Satoh T;Yagi H;Yanaka S;Yamaguchi T;Isoda Y;Iida S;Okamoto Y;Kato K
通讯作者：
Kato K
影响因子：
7
作者：
Hayes, Jerrard M.;Frostell, Asa;Rudd, Pauline M.
通讯作者：
Rudd, Pauline M.
影响因子：
4
作者：
Saremi, Leila;Esmaeilzadeh, Emran;Kadkhodazadeh, Mahdi
通讯作者：
Kadkhodazadeh, Mahdi
DOI：
10.1074/jbc.ra120.015516
发表时间：
2021-01
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Patel KR;Rodriguez Benavente MC;Lorenz WW;Mace EM;Barb AW
通讯作者：
Barb AW