Walochnik J, Sommer K, Obwaller A, Haller-Schober E-M, Aspöck H
Department of Medical Parasitology, Clinical Institute of Hygiene and Medical Microbiology, University of Vienna, Kinderspitalgasse 15, 1095 Vienna, Austria.
Parasitol Res. 2004 Mar;92(4):289-98. doi: 10.1007/s00436-003-1041-0. Epub 2004 Jan 13.
Free-living amoebae of the genus Acanthamoeba are the causative agents of Acanthamoeba keratitis (AK) and granulomatous amoebic encephalitis. Acanthamoebae occur ubiquitously in the environment and are thus a constant cause of antigenic stimulation. In a previous study we have shown that compared to control sera, AK patients exhibit markedly lower immunoreactivities to whole cell antigen of Acanthamoeba spp. As the pathogenicity of acanthamoebae primarily relies on the excretion of proteins, it was the aim of the present study to investigate the immunoreactivity of metabolic antigen from different Acanthamoeba strains of varying pathogenicity. Three Acanthamoeba strains, one highly pathogenic, one non-pathogenic but thermophilic and one non-thermophilic non-pathogenic, were used for antigen extraction. The antigen was harvested before and after contact with human cells and all strains were tested with AK sera and with sera from healthy individuals. It was shown that the somatic protein profiles of the Acanthamoeba strains correlated to the morphological groups, and that within morphological group II-the group associated with AK-the profiles of the metabolic antigens correlated to strain pathogenicity. Moreover, it was shown that the control sera showed markedly higher immunoreactivities than the sera of the AK patients and that this immunoreactivity was generally higher to the non-pathogenic strains than to the pathogenic strain. Altogether our results once again raise the question of whether there is an immunological predisposition in AK. To our knowledge this is the first study on the immunoreactivity of metabolic antigen of acanthamoebae.
棘阿米巴属的自由生活阿米巴是棘阿米巴角膜炎（AK）和肉芽肿性阿米巴脑炎的病原体。棘阿米巴在环境中普遍存在，因此是抗原刺激的持续来源。在先前的一项研究中，我们已经表明，与对照血清相比，AK患者对棘阿米巴属全细胞抗原的免疫反应性明显较低。由于棘阿米巴的致病性主要依赖于蛋白质的分泌，本研究的目的是调查来自不同致病性棘阿米巴菌株的代谢抗原的免疫反应性。使用了三株棘阿米巴菌株，一株高致病性，一株非致病性但嗜热，一株非嗜热非致病性，用于抗原提取。在与人类细胞接触前后收集抗原，并用AK患者血清和健康个体的血清对所有菌株进行检测。结果表明，棘阿米巴菌株的体细胞蛋白质谱与形态学组相关，并且在形态学组II（与AK相关的组）内，代谢抗原的谱与菌株致病性相关。此外，结果表明对照血清的免疫反应性明显高于AK患者的血清，并且这种免疫反应性通常对非致病性菌株比对致病性菌株更高。总之，我们的结果再次提出了AK是否存在免疫易感性的问题。据我们所知，这是第一项关于棘阿米巴代谢抗原免疫反应性的研究。
