Schoppel K, Hassfurther E, Britt W, Ohlin M, Borrebaeck C A, Mach M
Institut für Klinische und Molekulare Virologie, Universität Erlangen-Nürnberg, Germany.
Virology. 1996 Feb 1;216(1):133-45. doi: 10.1006/viro.1996.0040.
Glycoprotein B (gB, gpUL55) is a major antigen for the induction of neutralizing antibodies against human cytomegalovirus, making it an attractive antigen for active and passive immunoprophylaxis. The immunodominant region on gB is the antigenic domain 1 (AD-1), a complex structure which requires a minimal linear amino acid sequence of more than 75 amino acids (aa 552-635) for antibody binding. We have analyzed the fine specificity of neutralizing and nonneutralizing AD-1-binding monoclonal antibodies. Point mutations were introduced into AD-1 and mutants were expressed as bacterial fusion proteins. The antigens were analyzed in immunoblots using a panel of 13 human and murine monoclonal antibodies. Complete loss of binding of all antibodies was observed with mutations at cysteine residues 573 and 610 as well as with a combinatorial exchange of prolines at position 577 and 613. The remaining mutations had different effects on antibody binding. Six individual recognition patterns were observed, indicating various antigenic substructures on AD-1. Changing the Fc portions of 3 murine monoclonal antibodies to human IgG1 showed that neutralization of AD-1-binding immunoglobulins is exerted by different mechanisms. Dependent on the recognized substructure within AD-1, avidity-dependent as well as Fc portion-mediated effects were observed.
糖蛋白B（gB，gpUL55）是诱导针对人巨细胞病毒的中和抗体的主要抗原，使其成为主动和被动免疫预防的有吸引力的抗原。gB上的免疫显性区域是抗原结构域1（AD-1），这是一种复杂结构，抗体结合需要至少75个氨基酸的最小线性氨基酸序列（第552-635位氨基酸）。我们分析了中和及非中和性AD-1结合单克隆抗体的精细特异性。将点突变引入AD-1，并将突变体表达为细菌融合蛋白。使用一组13种人源和鼠源单克隆抗体在免疫印迹中分析抗原。在半胱氨酸残基573和610处发生突变以及在第577和613位脯氨酸的组合交换时，观察到所有抗体的结合完全丧失。其余突变对抗体结合有不同影响。观察到六种个体识别模式，表明AD-1上存在各种抗原亚结构。将3种鼠源单克隆抗体的Fc部分改为人类IgG1表明，AD-1结合免疫球蛋白的中和作用是通过不同机制发挥的。根据AD-1内识别的亚结构，观察到了亲和力依赖性以及Fc部分介导的效应。
