Engineered antibodies of IgG1/IgG3 mixed isotype with enhanced cytotoxic activities
Engineered antibodies of IgG1/IgG3 mixed isotype with enhanced cytotoxic activities
复制标题
DOI：
10.1158/0008-5472.can-07-6297
复制
发表时间：
2008-05-15
期刊：
影响因子：
11.2
通讯作者：
Niwa, Rinpei
中科院分区：
文献类型：
--
作者：
Natsume, Akito;In, Mika;Niwa, Rinpei
增强抗体的多种效应功能可能是一种很有前途的抗体治疗方法。我们之前已经报道过，从Fc连接的寡糖中去除岩藻糖大大增强了治疗性抗体的抗体依赖性细胞毒性(ADCC)。在这里，我们报道了一种独特的方法来增强补体依赖细胞毒(CDC)，这是抗肿瘤抗体的另一个重要效应功能，通过使用人IgG1/IgG3嵌合亚型的工程恒定区。我们系统地改组了IgG1和IgG3的恒定结构域，以产生一套全面的抗CD20抗体的混合嵌合亚型。其中，变异体1133，由来自IgG1的CH1和铰链以及来自IgG3的Fc组成，意外地显示出明显的CD增强，超过了野生型水平。然而，它缺乏蛋白A结合能力，这是工业化生产的一个重要特征。为了消除这一缺陷，用IgG1取代了COOH末端CH3结构域1133的一部分，导致蛋白A结合的完全恢复，而不影响增强的CDC和ADCC活性。在CD52抗原/抗体系统中也显示了嵌合同种异型CDC的增强作用。变异体的ADCC活性也因其碳水化合物结构中没有岩藻糖而最大化，这是以前在野生型抗体中观察到的现象。在食蟹猴模型中证实了一种突变体的增强细胞毒性。这些发现表明，具有IgG1/IgG3嵌合恒定区和具有双重增强细胞毒功能的非岩藻糖化低聚糖的变异抗体可能是下一代治疗性抗肿瘤抗体的改进。
Enhancement of multiple effector functions of an antibody may be a promising approach for antibody therapy. We have previously reported that fucose removal from Fc-linked oligosaccharides greatly enhances antibody-dependent cellular cytotoxicity (ADCC) of therapeutic antibodies. Here, we report a unique approach to enhance complement-dependent cytotoxicity (CDC), another important effector function of antitumor antibodies, by using engineered constant region of human IgG1/IgG3 chimeric isotypes. We systematically shuffled constant domains of IgG1 and IgG3 to generate a comprehensive set of mixed chimeric isotypes of anti-CD20 antibodies. Among these, the variant 1133, consisting of the CH1 and the hinge each from IgG1 and the Fc from IgG3 was unexpectedly found to exhibit markedly enhanced CD that exceeded wild-type levels. However, it lacked protein A-binding capacity, an important feature for the industrial production. To eliminate this deficiency, a portion in COOH-terminal CH3 domain of 1133 was substituted with IgG1, resulting in full recovery of protein A binding without compromising the enhanced CDC and ADCC activities. The CDC-enhancing effect using a chimeric isotype was also shown in CD52 antigen/antibody system. The ADCC activity of the variants was also maximized by the absence of fucose from its carbohydrate structure, a phenomenon that has previously been observed for wild-type antibodies. Enhanced cytotoxicity of a variant was confirmed in a cynomolgus monkey model. These findings suggest that the variant antibodies with IgG1/IgG3 chimeric constant regions and nonfucosylated oligosaccharides that possess dual-enhanced cytotoxic functions may be an improvement for the next generation of therapeutic antitumor antibodies.