Buchvald D, Maeland J A
Department of Microbiology, Faculty of Medicine, University of Trondheim, Norway.
APMIS. 1992 May;100(5):470-8.
Extract obtained by ultrasonic disruption of Helicobacter pylori bacteria contained a protein with subunit molecular mass of 25 kD which bound antibodies in sera from patients with H. pylori-associated disease. The protein was purified by gel permeation and elution from SDS-polyacrylamide gel slices, and was used to raise an anti-25-kD protein-specific rabbit serum. Using the antiserum in experiments, the results indicated the following: The protein exists as covalently linked dimers (45 kD) of the 25-kD subunits. Variable numbers of non-covalently linked copies of the dimers make up the native protein. The protein was susceptible to digestion by papain, pronase, and trypsin. Pepsin cleaved off a fragment of approximately 2 kD. A small share of the protein was exposed at the bacterial cell surface, the greatest share being localized internally. The protein was not secreted and it was probably not an integral part of the outer membrane. It was produced in variable quantity by all of 11 H. pylori strains tested and was a major protein in some strains. A cross-reacting protein with subunit size of 25 kD was also produced by Campylobacter jejuni strains, but not by any of a variety of other bacteria. Since both H. pylori and C. jejuni infection occur with a high frequency. the cross-reacting 25-kD protein may interfere unfavourably with the diagnostic specificity of serological tests for infection caused by these bacteria.
通过超声破碎幽门螺杆菌获得的提取物中含有一种亚基分子量为25kD的蛋白质，该蛋白质能与幽门螺杆菌相关疾病患者血清中的抗体结合。该蛋白质通过凝胶渗透和从SDS-聚丙烯酰胺凝胶切片上洗脱进行纯化，并用于制备抗25kD蛋白质特异性兔血清。在实验中使用该抗血清，结果表明：该蛋白质以25kD亚基的共价连接二聚体（45kD）形式存在。不同数量的非共价连接二聚体拷贝构成了天然蛋白质。该蛋白质易被木瓜蛋白酶、链霉蛋白酶和胰蛋白酶消化。胃蛋白酶切割掉了一个约2kD的片段。该蛋白质有一小部分暴露在细菌细胞表面，大部分位于细胞内部。该蛋白质不分泌，可能不是外膜的组成部分。在所测试的11株幽门螺杆菌菌株中，该蛋白质的产量各不相同，在某些菌株中是主要蛋白质。空肠弯曲菌菌株也产生一种亚基大小为25kD的交叉反应蛋白，但其他多种细菌均不产生。由于幽门螺杆菌和空肠弯曲菌感染的发生率都很高，这种交叉反应的25kD蛋白质可能会对这些细菌感染的血清学检测的诊断特异性产生不利干扰。
