Miyashita H, Hara T, Tanimura R, Tanaka F, Kikuchi M, Fujii I
Protein Engineering Research Institute, Osaka, Japan.
Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):6045-9. doi: 10.1073/pnas.91.13.6045.
Immunization with a single haptenic transition-state analog generates a few catalytic antibodies among the dozens of antibodies capable of binding the hapten. The diversity of the immune response has raised some fundamental issues, such as How do catalytic and noncatalytic antibodies differ on a structural basis? To address this issue, the variable region primary sequences of 11 antibodies (including 6 catalytic and 5 noncatalytic antibodies) elicited against a single haptenic transition-state analog were deduced from cDNA sequences. Cluster analyses using phylogenetic trees constructed by the neighbor-joining method have revealed that the amino acid sequences of noncatalytic antibodies bear no relationship to one another, while the catalytic antibodies share significant structural identity. Furthermore, no catalytic antibodies possessing amino acid sequences with high homology to those of noncatalytic antibodies were detected. Five catalytic antibodies examined showed 89-95% and 74-84% sequence homologies in the complete light- and heavy-chain variable regions, respectively. Thus, it seems likely that the catalytic antibodies elicited against a single hapten use the canonical set of variable region genes. Interestingly, one catalytic antibody showed only limited sequence similarity to the other catalytic antibodies and was found to exhibit a distinctly different substrate specificity. From the broad range of their binding constants to the hapten, it is unlikely that highly homologous catalytic antibodies are generated as a result of simple high-affinity choices. These results emphasize the utility of rationally designed transition-state analogs for the induction of antibody molecules with catalytic activity.
用单个半抗原过渡态类似物进行免疫，在能够结合该半抗原的数十种抗体中会产生少数催化抗体。免疫反应的多样性引发了一些基本问题，比如催化抗体和非催化抗体在结构基础上有何不同？为了解决这个问题，从cDNA序列推导了针对单个半抗原过渡态类似物产生的11种抗体（包括6种催化抗体和5种非催化抗体）的可变区一级序列。使用邻接法构建的系统发育树进行聚类分析表明，非催化抗体的氨基酸序列彼此之间没有关系，而催化抗体具有显著的结构同一性。此外，未检测到氨基酸序列与非催化抗体高度同源的催化抗体。所检测的5种催化抗体在完整的轻链和重链可变区分别显示出89 - 95%和74 - 84%的序列同源性。因此，针对单个半抗原产生的催化抗体似乎使用了可变区基因的标准集合。有趣的是，一种催化抗体与其他催化抗体仅显示出有限的序列相似性，并且发现其表现出明显不同的底物特异性。从它们与半抗原的广泛结合常数范围来看，不太可能由于简单的高亲和力选择而产生高度同源的催化抗体。这些结果强调了合理设计的过渡态类似物在诱导具有催化活性的抗体分子方面的效用。
