Biochemical and Immunological Studies on Pathogenic Factors of Candida Albicans

本文从生物学和免疫学两个方面研究了白念珠菌（Candida albicans）的致病因素。白色念珠菌虽然过氧化氢酶在C. H_2O_2刺激的酵母细胞对中性粒细胞杀伤的抵抗力没有增加，表明应激诱导的过氧化氢酶不是白念珠菌胞内寄生的因素。其次，我们确定了粘附素的性质，粘附素是白色念珠菌粘附所必需的。白色念珠菌宿主表皮细胞。C.抗原缺陷突变体的粘附能力。白念珠菌血清型A特异性抗原（抗原6）对上皮细胞的作用明显低于亲本和回复株。对来自亲本和突变体的纯化甘露聚糖的^1H-核磁共振光谱分析以及其乙酰化产物的分级分离显示， ...更多信息 突变体甘露聚糖失去了具有末端β-连接的甘露六糖（M6）。M6对C.用抗原6特异性单克隆抗体检测白念珠菌，表明M6是抗原6的决定簇。这些结果表明，M6的C.白念珠菌（A）甘露聚糖作为配体主要参与粘附机制。此外，这一发现得到了以下证据的进一步支持：具有抗原6的念珠菌属物种（即，e.热带假丝酵母（C.tropicalis）的抗原性高于无抗原6的种（i. tropicalis）。e. C. guilliermondii.）最后，我们探讨了C.白色念珠菌为了确定抑制二型性的机制，通过几种抗真菌剂检查了麦角甾醇生物合成途径中的各个步骤对二型性的抑制作用。结果表明，二型性的抑制与胞质膜麦角甾醇的丢失有关。少

We studied the biological and immunological aspects of pathogenic factors of Candida albicans, a main pathogen for candidiasis.First, we investigated the involvement of catalase in pathogenic factors of the intracellular parasitism of C. albicans. Although catalase production in C. albicans increased by H_2O_2 stimulation, no increase in resistance to killing by neutrophils was observed in the H_2O_2-stimulated yeast cells, indicating that stress-induced catalasre is not a factor of the intracellular parasitism of C. albicans.Second, we determined the nature of adhesin which is required for adherence of C. albicans to host epitherial cells. Adherence ability of antigen mutants defective in C. albicans serotype A-specific antigen (antigen 6) to epitherial cells markedly reduced as compared with their parent and reverlants. ^1H-nuclear magnetic resonance spectral analyses of the purified mannans from the parent and the mutants, and fractionation of their acetolyzed products revealed that … More the mutant mannan lost mannohexaose (M6) with terminal beta-linkage. The fact that the M6 inhibited the agglutination of C. albicans with antigen 6-specific monoclonal antibody showed the significance of M6 as the determinant for antigen 6. These results suggest that the side chains of M6 specific for C. albicans (A) mannan are largely involved in the adherence mechanisms as ligands. Moreover, such finding was supported finding was supported further by the evidence that adherence ability of antigen 6-possessing Candida species (i. e. C.tropicalis) was higher than that of antigen 6-nonpossessing species (i. e. C. guilliermondii.)Finally, we investigated the biochemical mechanisms for dimorphism of C. albicans. To determine the mechanism of inhibition of dimorphism, effect of inhibition of various steps in the pathway for ergosterol biosynthesis on dimorphism were examined by several antifungal agents. As a results, it is suggested that inhibition of dimorphism is related to the loss of ergosterol in cytoplasmic membrane. Less