Analysis of the pathogenicity of Acanthamoeba and protective immunity to Acanthamoeba in humans.

分析了人体对两种自由生活的阿米巴原虫多食阿米巴（Ap）和卡氏阿米巴（Ac）抗原的宿主免疫应答。无论他们过去的历史棘阿米巴病，一半的健康日本成年人表现出显着的增殖外周血T细胞的Ap和Ac粗抗原在体外。所有测试的应答T细胞都是CD 3 ^+4^+8^-和TCR-α ^+，当测试它们的精氨酸生成谱时，它们在功能上属于Thl亚型。尽管显着的T细胞增殖反应，Ap和Ac，没有检测到特异性IgG抗体，观察到，表明在健康对照组中的细胞和体液免疫的阿米巴抗原的解离。我们测试了一个可能患有阿米巴脑膜脑炎的病人，然而，她没有表现出可检测到的T细胞共振，即使是致病的阿米巴。有人认为，这种失败的T细胞反应阿米巴可能已参与发病机制。我们 ...更多信息 分析了由遗传背景差异决定的阿米巴原虫的人T细胞表位的异质性。通过使用对Ap或Ac具有特异性的人CD 4 ^+ T细胞克隆，我们观察到Ap和Ac共有的T细胞表位的存在，或者是物种特异性的。此外，似乎有些表位仅在阿米巴的一部分表达。然而，我们观察到，这种多样性的抗原决定簇没有直接关系的致病力的阿米巴。结合这些结果，我们想得出结论，不是所有的，而是相当数量的健康个体被致病性阿米巴致敏，导致阿米巴特异性Thl细胞应答的诱导。很可能这些T细胞通常识别阿米巴属的共同表位，然而，一些T细胞表位在一个物种内是异质的。宿主免疫应答的异质性和阿米巴抗原表位的异质性可能是棘阿米巴病免疫致病的原因之一。少

Host immune responses to antigens of two species of free-living amoebae, Acanthamoeba polyphaga (Ap) and A.castellanii (Ac) , were analyzed in humans. Regardless of their past history of acanthamoebiasis, a half of healthy Japanese adults showed significant proliferation of peripheral blood T cells to both Ap and Ac crude antigens in vitro. All the responding T cells tested were CD3^+4^+8^-and TCR-alphabeta^+, and those were functionally of Thl subtype when their cytokine-production profiles were tested. In spite of significant T cell proliferative responses to Ap and Ac, no detectable specific IgG antibodies were observed, suggesting dissociation of cellular and humoral immunity to Acanthamoeba antigens in healthy controls. We tested a probable patient with amoebic meningoencephalitis, however, she showed no detectable T-cell resonses even to the causative amoeba. It was suggested that such a failure of T-cell responses to Acanthamoeba might have been involved in the pathogenesis. We … More analyzed a heterogeneity of human T cell epitopes of Acanthamoeba determined by differencies in genetic background. By using human CD4^+T-cell clones specific for Ap or Ac, we observed the existence of T-cell epitopes shared by both Ap and Ac, or those which were species-specific. Furthermore, it seemed likely that some epitopes were expressed only a part of Acanthamoeba. However, we observed that such a diversity in their epitopes were not directly related to the strength of pathogenicity of Acanthamoeba. Togeter with those results, we would like to conclude that not all, but considerable number of healthy individuals are sensitized with the pathogenic Acanthamoeba resulting induction of Acanthamoeba-specific Thl cell responses. It was likely that those T cells generally recognized a common epitope (s) of the genus Acanthamoeba, however, some T-cell epitopes were heterogenous within a species. Those heterogeneities both in the host immune responses and the amoebic epitopes might have contribution for the immunopathogenicities of acanthamoebiasis in humans. Less