Elsayed S, Apold J, Holen E, Vik H, Florvaag E, Dybendal T
Laboratory of Clinical Biochemistry, University Hospital, University of Bergen, Norway.
Scand J Clin Lab Invest Suppl. 1991;204:17-31.
Three major allergens from cod fish, egg white and tree pollen, were characterized by studies on their allergenic and antigenic structures. The major allergen of cod fish, Allergen M "parvalbumins pI 4.75", is composed of 113 amino acid residues with a molecular weight of 12,328 daltons. It comprised three domains, AB, CD and EF, consisting of 3 helices interspaced by one loop. Each of the loops of the CD and EF domains each coordinates one Ca2+. The antigenicity and allergenicity of Allergen M was deduced from studying the modified protein and some particular synthetic peptides. Three sites were encompassing IgE binding epitopes namely peptides 33-44, 65-74 and 88-96. A novel peptide (49-64), of the CD-domain, was demonstrated to be allergenically/antigenically active and cross reactive with birch pollen allergen, which incidentally was used as a negative control. This site encompassed two repetitive sequences (D-E-D-K) and (D-E-L-K), suggested to be mutually critical for the specificity of antibody binding. This hypothesis was reconfirmed by SPPS of several analogous peptides of region 39-64. Furthermore, peptide 88-103 of the EF-domain was similarly synthesized; it functioned as a monovalent hapten, blocking and not eliciting allergic reaction. Moreover, peptide 13-32 of domain AB, the non-calcium binding domain, was thoroughly tested. The results of PK inhibition showed clear activity and the peptide was found to function at the level of a divalent determinant. Ovalbumin (OA) is the most dominant of five major allergens of egg white and universally used as model protein. OA allergenic epitopes were shown to be mainly determined by the primary structure and depend on certain peptide chain length. The N-terminal decapeptide (OA 1-10) was shown to react with reaginic IgE. Direct skin test on egg allergic patients, showed no activity and the site was therefore concluded to encompasses one single Ig binding haptenic epitope. Peptide OA 323-339, was demonstrated to be valuable in studies of T-cell recognition of protein antigens. Three analogous peptides of this region were prepared and clearly shown to be immunogenic in rabbits and to bind specific IgE from patients allergic to egg. OA 323-339 was concluded to encompass an allergenic and antigenic epitope which was recognized by human and rabbit B-lymphocytes. Eight peptides in the region 11-122 were similarly synthesized. A test battery was performed to study this region using rabbit polyclonal antibodies and human specific IgE. Some of these sites were involved in binding of particular Ig paratopes. Five immunogenic peptides from the major allergens of tree pollen extracts (segment 23-38), were synthesized. The selection of those peptides was setteled using two algorithms for providing the optimal hydrophobicity.(ABSTRACT TRUNCATED AT 400 WORDS)
通过对鳕鱼、蛋清和树花粉的三种主要过敏原的致敏和抗原结构研究，对其进行了表征。鳕鱼的主要过敏原变应原M“肌钙蛋白pI 4.75”由113个氨基酸残基组成，分子量为12328道尔顿。它由三个结构域AB、CD和EF组成，由3个螺旋和一个环间隔开。CD和EF结构域的每个环都配位一个Ca2+。通过研究修饰蛋白和一些特定的合成肽，推断出变应原M的抗原性和致敏性。三个位点包含IgE结合表位，即肽33 - 44、65 - 74和88 - 96。CD结构域的一种新型肽（49 - 64）被证明具有致敏/抗原活性，并与桦树花粉过敏原交叉反应，顺便用作阴性对照。该位点包含两个重复序列（D - E - D - K）和（D - E - L - K），提示它们对抗体结合的特异性相互关键。通过对区域39 - 64的几种类似肽进行固相肽合成，再次证实了这一假设。此外，类似地合成了EF结构域的肽88 - 103；它作为单价半抗原起作用，可阻断而不引发过敏反应。此外，对非钙结合结构域AB的肽13 - 32进行了全面测试。PK抑制结果显示出明显的活性，并且发现该肽在二价决定簇水平起作用。卵清蛋白（OA）是蛋清五种主要过敏原中最主要的，普遍用作模型蛋白。OA致敏表位主要由一级结构决定，并取决于特定的肽链长度。N端十肽（OA 1 - 10）被证明与反应素IgE反应。对鸡蛋过敏患者的直接皮肤试验显示无活性，因此得出该位点包含一个单一的Ig结合半抗原表位的结论。肽OA 323 - 339被证明在蛋白质抗原的T细胞识别研究中有价值。制备了该区域的三种类似肽，并清楚地显示在兔子中具有免疫原性，并能结合对鸡蛋过敏患者的特异性IgE。得出OA 323 - 339包含一个被人和兔B淋巴细胞识别的致敏和抗原表位的结论。类似地合成了区域11 - 122中的八个肽。使用兔多克隆抗体和人特异性IgE进行了一组测试来研究该区域。其中一些位点参与特定Ig互补位的结合。合成了来自树花粉提取物主要过敏原的五种免疫原性肽（片段23 - 38）。使用两种算法选择这些肽以提供最佳疏水性。（摘要截短至400字）
