THE ORIGIN OF SPECIFICITY OF ANTIGEN-ANTIBODY INTERACTION

正如在另一份报告中所描述的，在这种情况下，蛋白质折叠的研究 第一节提出了一个假设，即（1）一个以前未知的 蛋白质的疏水核心存在非共价相互作用;（2） 这种新的相互作用，称为核心回路相互作用，是放热的， 由在核中形成闭环的接触基团介导;和 (3)核心环路的相互作用对群的细节很敏感 联系，因此有能力订购核心组。 抗原-抗体相互作用类似于两个核心环相互作用。 关键方面。首先，核心回路相互作用和 抗原-抗体相互作用识别单个氨基酸取代 即使不涉及极性变化。其次，核心回路和 抗原和抗体之间的界面没有溶剂。因此我们 推测抗原-抗体相互作用的特异性具有其 起源于核心相互作用回路， 抗原抗体界面为了测试这个想法，6个杂交瘤细胞系 生产IgG单克隆抗体的酵母异-1-细胞色素c已经制备， 前几年。 我们的策略是：（1）克隆单个单克隆的cDNA; (2)测序cDNA以推断氨基酸序列;（3） 计算机构建单克隆抗体的三维结构 同源性建模，以检查抗原结合位点;（4）开发一个 克隆cDNA的表达系统;（5）鉴定疏水 通过计算机建模的单克隆分子的结构域的核心;（6） 通过定点诱变使核心残基突变（一次一个）; (7)表达突变的cDNA以检查突变对 抗原-抗体相互作用;和（8）如果（7）的结果是阳性， (7)将用相同结构域的不同核心残基重复， 也可以用不同结构域的核心残基来映射 影响抗原-抗体相互作用。如果假设是正确的， 远离抗原结合位点的核心基团应该影响 抗原抗体相互作用。 近年来，从杂交瘤细胞系的mRNA中克隆cDNA 2-96-12（上述6种杂交瘤细胞系之一）进行了筛选。 筛选由此获得的cDNA文库（cDNA文库）中克隆的存在 含有κ轻链cDNA。因此，筛选出37个阳性克隆。 提纯

As described in another report, the studies of protein folding in this Section have led to the hypothesis that (1) a previously unknown non-covalent interaction exists in the hydrophobic cores of proteins; (2) this new interaction, called the core loop interaction, is exothermic and mediated by the contacting groups which form a closed loop in the core; and (3) the core loop interaction is sensitive to the detail of the group contact and therefore has the ability to order the core groups. Antigen-antibody interaction resembles this core loop interaction in two critical aspects. First, both the core loop interaction and antigen-antibody interaction recognize a single amino acid substitution even if no polarity - change is involved. Second, both the core loop and the interface between antigen and antibody are devoid of solvent. Thus, we speculate that the specificity of antigen-antibody interaction has its origin in the core interaction loop which would form within or across the antigen antibody interface. To test this idea 6 hybridoma cell lines producing IgG monoclonals to yeast iso-1-cytochrome c have been prepared in the previous years. Our strategy is that (1) cloning the cDNA of the individual monoclonals; (2) sequencing of the CDNA to deduce the amino acid sequences; (3) constructing the three dimensional structures of monoclonals by computer homology modelling to examine the antigen binding sites; (4) developing an expression system for the cloned cDNA; (5) identifying the hydrophobic cores of the domains of the monoclonal molecules by computer modelling; (6) mutating the core residues (one at a time) by site directed mutagenesis; (7) expressing the mutated CDNA to examine the influence of the mutation on antigen-antibody interaction; and (8) if the results of (7) are positive, (7) will be repeated with different core residues of the same domain and also with the core residues of different domains to map the groups which influence antigen-antibody interaction. If the hypothesis is correct, the core groups remote from the antigen binding site should influence the antigen-antibody interaction. In the current year cloning cDNA prepared from mRNA of hybridoma cell line 2-96-12 (one of the above 6 hybridoma cell lines) has been carried out The cDNA library (phages) thus obtained was screened for the presence of clones containing the kappa light chain cDNA. Thus, 37 positive clones were purified.