Kinetics of anti-carcinoembryonic antigen antibody internalization: effects of affinity, bivalency, and stability
Kinetics of anti-carcinoembryonic antigen antibody internalization: effects of affinity, bivalency, and stability
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DOI：
10.1007/s00262-008-0518-1
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发表时间：
2008-12-01
影响因子：
5.8
通讯作者：
Wittrup, K. Dane
中科院分区：
文献类型：
--
作者：
Schmidt, Michael M.;Thurber, Greg M.;Wittrup, K. Dane
理论分析表明，结合抗体的细胞内化和卡替显着地导致向肿瘤中的渗透不良。在这里，我们定量评估的内化抗体和抗体片段对常见的靶抗原癌胚抗原（CEA）。尽管CEA通常被称为非内化或脱落抗原，但抗CEA抗体和抗体片段显示出被LS 174 T细胞缓慢内吞，半衰期为10-16小时，该时间尺度与不存在抗体时CEA的代谢周转率一致。在亲和力、对蛋白酶消化的稳定性和效价方面具有显著差异的抗CEA单链可变片段（scFv）表现出类似的结合抗体摄取速率。相比之下，一种抗CEA IgG表现出独特的结合和运输特性，在饱和时每个细胞结合的分子是其两倍，并且在结合后细胞内化显著更快。本文测量的内化速率可用于简单的计算模型中以预测这些抗体在肿瘤球状体中的微分布。
Theoretical analyses suggest that the cellular internalization and catabolism of bound antibodies contribute significantly to poor penetration into tumors. Here we quantitatively assess the internalization of antibodies and antibody fragments against the commonly targeted antigen carcinoembryonic antigen (CEA). Although CEA is often referred to as a non-internalizing or shed antigen, anti-CEA antibodies and antibody fragments are shown to be slowly endocytosed by LS174T cells with a half-time of 10-16 h, a time scale consistent with the metabolic turnover rate of CEA in the absence of antibody. Anti-CEA single chain variable fragments (scFvs) with significant differences in affinity, stability against protease digestion, and valency exhibit similar uptake rates of bound antibody. In contrast, one anti-CEA IgG exhibits unique binding and trafficking properties with twice as many molecules bound per cell at saturation and significantly faster cellular internalization after binding. The internalization rates measured herein can be used in simple computational models to predict the microdistribution of these antibodies in tumor spheroids.