Wallick S C, Kabat E A, Morrison S L
Department of Microbiology, Columbia University College of Physicians and Surgeons, NY 10032.
J Immunol. 1989 Feb 15;142(4):1235-44.
Gene transfection and expression techniques have been used to produce three antibodies specific for alpha (1----6) linked dextran B512 with altered isotypes and J kappa regions. Expression of the L chain V region joined to J kappa 4 or J kappa 5 instead of to J kappa 2 reduced or abolished dextran binding. One antidextran with a reduced binding constant for dextran had the same combining site size as the parental mAb. Transfectoma Ig unreactive with dextran B512 did not bind to other class I or class II dextrans. Antibodies with J kappa 4-containing L chains expressed the 10.16.1 (anti-alpha(1----6) dextran) idiotype. In contrast variants expressing L chains with J kappa 5 lost idiotype expression, except when oligosaccharide is present on VH; all antibodies with J kappa 5 L chains continued to bind dextran but with reduced affinity. The presence of carbohydrate in VH may alter the conformation of both paratope and idiotope. Alteration of H chain isotype did not appear to significantly alter the ability of the antidextran to bind Ag; an exception may be that switching V regions to the IgM C region may decrease the apparent affinity for Ag.
基因转染和表达技术已被用于制备三种针对α(1→6)连接的葡聚糖B512的特异性抗体，其同种型和Jκ区域有所改变。与Jκ4或Jκ5而非Jκ2连接的L链V区的表达降低或消除了葡聚糖结合。一种对葡聚糖结合常数降低的抗葡聚糖抗体与亲本单克隆抗体具有相同的结合位点大小。与葡聚糖B512无反应性的转染瘤Ig不与其他I类或II类葡聚糖结合。含有Jκ4的L链的抗体表达10.16.1（抗α(1→6)葡聚糖）独特型。相反，表达带有Jκ5的L链的变体失去了独特型表达，除非VH上存在寡糖；所有带有Jκ5 L链的抗体继续结合葡聚糖，但亲和力降低。VH中碳水化合物的存在可能会改变互补位和独特位的构象。H链同种型的改变似乎并未显著改变抗葡聚糖抗体结合抗原的能力；一个例外可能是将V区转换为IgM C区可能会降低对抗原的表观亲和力。
