Ionescu-Matiu I, Kennedy R C, Sparrow J T, Culwell A R, Sanchez Y, Melnick J L, Dreesman G R
J Immunol. 1983 Apr;130(4):1947-52.
A synthetic peptide (SP1), corresponding to the amino acid residues 122 through 137 of the major polypeptide derived from hepatitis B surface antigen (HBsAg), subtype ayw, was analyzed for the presence of the major epitopes of HBsAg. Both a cyclic form, produced by introduction of an intrachain disulfide bond, and a linear form of the peptide were characterized. A panel of monoclonal antibodies with defined specificity for the cross-reactive group a antigenic determinant(s) and for the y and w subtype specificities was used for this analysis. The cyclic, but not the linear, form of SP1 reacted with five of 14 anti-a monoclonal antibodies, demonstrating that the cyclic peptide contains a conformation-dependent a epitope. Only one anti-a antibody was found to react with both cyclic and linear forms of SP1. Because SP1 failed to react with the remaining 8 anti-a monoclonal antibodies, it was concluded that the a antigenic reactivity associated with HBsAg contains an additional epitope(s) unrelated to that expressed on SP1. Both cyclic and linear SP1 reacted with three of three anti-y monoclonal antibodies, indicating that a sequential y epitope is also present on SP1; no w reactivity was detected. Analysis of the idiotypes associated with the monoclonal antibodies showed those that combined with cyclic SP1 also inhibited the binding of a common human anti-HBs (CHBs) idiotype with its rabbit anti-idiotype serum, whereas a monoclonal antibody that did not react with the cyclic SP1 epitope failed to inhibit the CHBs idiotype-anti-idiotype reaction. Thus, the conformational a epitope present on cyclic SP1 appears to contain the predominant epitope recognized by humans in response to a natural HBV infection.
对一种合成肽（SP1）进行了分析，以确定其是否存在乙型肝炎表面抗原（HBsAg）主要多肽的主要表位。该合成肽对应于源自ayw亚型HBsAg的主要多肽的第122至137位氨基酸残基。同时对通过引入链内二硫键产生的环化形式以及该肽的线性形式进行了表征。使用一组对交叉反应性a抗原决定簇以及y和w亚型特异性具有明确特异性的单克隆抗体进行了此项分析。SP1的环化形式而非线性形式与14种抗a单克隆抗体中的5种发生反应，表明环化肽含有构象依赖性a表位。仅发现一种抗a抗体与SP1的环化形式和线性形式均发生反应。由于SP1未与其余8种抗a单克隆抗体发生反应，因此得出结论，与HBsAg相关的a抗原反应性包含一个与SP1上表达的表位无关的额外表位。环化和线性SP1均与3种抗y单克隆抗体中的3种发生反应，表明SP1上也存在连续的y表位；未检测到w反应性。对与单克隆抗体相关的独特型分析表明，与环化SP1结合的那些抗体也抑制了常见人类抗HBs（CHBs）独特型与其兔抗独特型血清的结合，而未与环化SP1表位反应的单克隆抗体未能抑制CHBs独特型 - 抗独特型反应。因此，环化SP1上存在的构象a表位似乎包含人类在自然HBV感染后识别的主要表位。
