A versatile bifunctional chelate for radiolabeling humanized anti-CEA antibody with In-111 and Cu-64 at either thiol or amino groups: PET imaging of CEA-positive tumors with whole antibodies
A versatile bifunctional chelate for radiolabeling humanized anti-CEA antibody with In-111 and Cu-64 at either thiol or amino groups: PET imaging of CEA-positive tumors with whole antibodies
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DOI：
10.1021/bc700161p
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发表时间：
2008-01-01
影响因子：
4.7
通讯作者：
Shively, John E.
中科院分区：
文献类型：
--
作者：
Li, Lin;Bading, James;Shively, John E.
放射性标记的抗癌胚抗原（CEA）抗体有可能为各种人类肿瘤提供良好的图像，包括结肠、乳腺、肺和甲状腺髓样肿瘤。为了实现使用抗CEA抗体进行常规和重复性临床成像的目标，需要抗体具有对CEA的高亲和力、在正常组织中的低交叉反应性和摄取以及低免疫原性。人源化抗CEA抗体hT84.66-M5 A（M5 A）满足这些标准，具有> 10（10）M-1的亲和力常数，与正常组织中发现的CEA交叉反应抗原无反应性，并且>90%人蛋白质序列。放射性标记的抗体的常规临床使用的另一个要求是放射性标记的通用方法，其允许使用在其放射性发射和半衰期方面不同的多种放射性核素。我们描述了一种多功能的双功能螯合剂，DO 3A-VS（1，4，7-三（羧甲基）-10-（乙烯基砜）-1，4，7，10-四氮杂环十二烷），其结合一系列放射性金属，包括用于γ射线成像的In-111和用于正电子发射断层扫描（PET）的Cu-64，并且其可以以可忽略的免疫反应性损失与巯基（SH）在轻度还原的免疫球蛋白的铰链区或免疫球蛋白的表面赖氨酸（NH）中。基于我们比较放射性标记的抗CEA抗体在鼠模型中与人模型中的动力学的相关研究，我们预测Cu-64标记的完整的人源化抗体可用于临床中CEA阳性肿瘤的成像。
Radiolabeled anti-carcinoembryonic antigen (CEA) antibodies have the potential to give excellent images of a wide variety of human tumors, including tumors of the colon, breast, lung, and medullar thyroid. In order to realize the goals of routine and repetitive clinical imaging with anti-CEA antibodies, it is necessary that the antibodies have a high affinity for CEA, low cross reactivity and uptake in normal tissues, and low immunogenicity. The humanized anti-CEA antibody hT84.66-M5A (M5A) fulfills these criteria with an affinity constant of > 10(10) M-1, no reactivity with CEA cross-reacting antigens found in normal tissues, and >90% human protein sequence. A further requirement for routine clinical use of radiolabeled antibodies is a versatile method of radiolabeling that allows the use of multiple radionuclides that differ in their radioemissions and half-lives. We describe a versatile bifunctional chelator, DO3A-VS (1,4,7-tris(carboxymethyl)-10-(vinylsulfone)-1,4,7,10-tetraazacyclododecane) that binds a range of radiometals including In-111 for gamma-ray imaging and Cu-64 for positron emission tomography (PET), and which can be conjugated with negligible loss of immunoreactivity either to sulfhydryls (SH) in the hinge region of lightly reduced immunoglobulins or surface lysines (NH) of immunoglobulins. Based on our correlative studies comparing the kinetics of radiolabeled anti-CEA antibodies in murine models with those in man, we predict that Cu-64-labeled intact, humanized antibodies can be used to image CEA positive tumors in the clinic.