An analysis of idiotype expression in a high-affinity, somatically mutated variant of a germline-encoded anti-p-azobenzenearsonate antibody.
An analysis of idiotype expression in a high-affinity, somatically mutated variant of a germline-encoded anti-p-azobenzenearsonate antibody.
复制标题
种系编码的抗对偶氮苯胂酸抗体的高亲和力体细胞突变变体的独特型表达分析。
DOI：
10.1093/intimm/5.1.1
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发表时间：
1993
影响因子：
4.4
通讯作者：
Sharon,J
中科院分区：
文献类型：
--
作者：
Nisonoff,A;Oliveira,TM;Sharon,J
用两种多克隆(兔)和两种单抗(抗ID)试剂，我们研究了单抗36-71的结构相关性。单抗36-71是CRIAid家族的一个体细胞突变成员，与对偶氮苯磺酸(Ars)半抗原具有极高的亲和力。两株单抗主要与L 36-71链结合。多克隆抗体可与H链和L链相互作用。36-71位的VH和VL区的氨基酸序列与CRIAfamly的未突变原型抗Ars单抗36-65的氨基酸序列分别在8位和11位不同。在36-71L存在的情况下，通过诱变引入的36-65VH中只有三个替换足以恢复36-71ID的完整表达。先前已经证明，同样的三个取代使36-65的亲和力增加了200倍，达到与36-71相当的水平。X射线结晶学已经表明，其中两个取代引入了与亲和力增加一致的构象变化。我们认为，这些构象变化也可能解释了这三种氨基酸在ID表达中的关键作用。我们还发现，36-65对36-71与其多克隆抗ID相互作用的抑制作用很差，尽管这两个单抗中的半抗原接触残基是相同的，并且有证据表明(来自半抗原抑制)半抗原结合区是重要ID的一部分。同样，这两个单抗结合部位的构象差异可以解释这些观察到的现象。
Using two polyclonal (rabbit) and two monoclonal antl-ldlotype (anti-Id) reagents, we investigated structural correlates of the Id of mAb 36–71, a somatically mutated member of the CRIAId family that has an exceptionally high affinity for thep-azobenzenearsonate (Ars) hapten. The two monoclonal anti-Ids reacted principally with the L chain of 36–71. The polyclonal anti-Ids interacted with both the H and L chain. The amino acid sequences of the VHand VLregions of 36–71 differ in eight and 11 positions respectively from those of the anti-Ars mAb 36–65, an unmutated prototype of the CRIAfamily. In the presence of 36–71L only three substitutions In 36–65 VH, introduced by mutagenesis, sufficed to restore full expression of the 36–71 Id. The same three substitutions had previously been shown to increase the affinity of 36–65 by a factor of 200, to a level equivalent to that of 36–71. X-ray crystallography had indicated that two of these substitutions introduce conformational changes consistent with the increase in affinity. We propose that these conformational changes may also account for the critical role of the three amino acids in Id expression. We also found that 36–65 is a very poor Inhibitor of the interaction of 36–71 with Its polyclonal anti-Ids, despite identity of the hapten-contacting residues in the two mAbs and evidence (from hapten inhibition) that the hapten-binding region is part of an important Id. Again, a difference in conformation at the binding site of the two mAbs could account for these observations.