Pérez-Maceda B, López-Bote J P, Langa C, Bernabeu C
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Clin Chim Acta. 1991 Dec 16;203(2-3):153-65. doi: 10.1016/0009-8981(91)90287-m.
Antibodies in serum from some patients with rheumatoid arthritis, recognize bovine albumin present in the milk, as determined by immunoprecipitation analysis from 125I-milk extracts. This antigen was also immunoprecipitated from bovine sera. These and ELISA studies showed that BSA is preferentially recognized over other proteins present in the milk. Panel studies demonstrated that although the average reactivity for BSA was high, only one third of the sera tested displayed a reactivity above the mean. The possibility of a molecular mimicry mechanism in RA between this food antigen and other human antigens was investigated. A sequence alignment analysis showed that the residues 141-157 of bovine albumin significantly differed from the corresponding fragment of human albumin, but were highly homologous with human collagen type I, C1q and vitamin D binding protein. In support of the immunogenicity of this fragment, we found that representative RA sera displayed a specific reactivity for a synthetic peptide containing the BSA residues responsible for the homology. Furthermore, most of the epitopes recognized on BSA by the RA sera seem to be conformationally dependent as heat denaturation or reduction followed by alkylation lead to a diminished recognition.
通过对125I-牛奶提取物进行免疫沉淀分析确定，一些类风湿性关节炎患者血清中的抗体可识别牛奶中存在的牛血清白蛋白。这种抗原也可从牛血清中免疫沉淀出来。这些研究以及酶联免疫吸附测定研究表明，与牛奶中存在的其他蛋白质相比，牛血清白蛋白更易被识别。小组研究表明，虽然牛血清白蛋白的平均反应性较高，但所检测的血清中只有三分之一的反应性高于平均值。研究了类风湿性关节炎中这种食物抗原与其他人类抗原之间分子模拟机制的可能性。序列比对分析表明，牛血清白蛋白的141-157位残基与人类白蛋白的相应片段有显著差异，但与人类I型胶原蛋白、C1q和维生素D结合蛋白高度同源。为支持该片段的免疫原性，我们发现代表性的类风湿性关节炎血清对含有负责同源性的牛血清白蛋白残基的合成肽具有特异性反应。此外，类风湿性关节炎血清在牛血清白蛋白上识别的大多数表位似乎依赖于构象，因为热变性或还原后烷基化会导致识别能力下降。
