Role of specific determinants in mannan of Candida albicans serotype A in adherence to human buccal epithelial cells
Role of specific determinants in mannan of Candida albicans serotype A in adherence to human buccal epithelial cells
复制标题
A血清型白色念珠菌甘露聚糖中特定决定簇在粘附人口腔上皮细胞中的作用
作者：
Y. Miyakawa;Toshiharu Kuribayashi;K. Kagaya;Mamoru Suzuki;Takashi Nakase;Y. Fukazawa
白念珠菌A型具有一种特殊的抗原，命名为抗原6，存在于细胞表面的甘露糖中。为了确定白念珠菌细胞壁的甘露聚糖部分在与口腔上皮细胞黏附中的作用，我们用抗6抗原的凝集性单抗(MAb-6)筛选得到了抗原6缺陷的突变体。从突变体中纯化的甘露聚糖的~1H核磁共振波谱分析表明，与侧链的β-连接有关的信号丢失。此外，突变的甘露聚糖的乙酰化片段显示甘露六糖和甘露五糖的含量减少。突变的酵母细胞对脱落的口腔上皮细胞和人类口腔癌细胞的黏附能力显著降低。白念珠菌A、热带念珠菌和光滑念珠菌对细胞的粘附率明显高于缺乏抗原6的B型白念珠菌。白念珠菌A亲本的全部甘露聚糖抑制白念珠菌A与上皮细胞的黏附呈剂量依赖关系，而突变株的甘露聚糖则不能。此外，经MAb-6或多克隆因子6血清处理的白色念珠菌A的粘附率降低。白念珠菌A亲本、抗原突变体及其自发回复株的粘附性和与MAb-6的凝集性密切相关。这些结果表明，就甘露聚糖黏附而言，白念珠菌A与人口腔黏膜上皮细胞的黏附机制在很大程度上与A型血清特异性决定因素有关。
Candida albicans serotype A (C. albicans A) possesses a specific antigen, designated antigen 6, which resides in mannans on the cell surface. To determine the role of the mannan moiety of the C. albicans cell wall in adherence to buccal epithelial cells, we used antigen 6-deficient mutants which had been isolated by screening with an agglutinating monoclonal antibody against antigen 6 (MAb-6). 1H nuclear magnetic resonance spectral analysis of the purified mannans from the mutants showed a loss of the signals related to that beta-linkage of the side chains. Moreover, acetolyzed fragments of the mutant mannans showed a decreased amount of mannohexaose and mannopentaose. The mutant yeast cells exhibited significantly reduced ability to adhere both to exfoliated buccal epithelial cells and to a human buccal cell line. A number of strains of C. albicans A, C. tropicalis, and C. glabrata, all of which bear antigen 6, showed significantly higher adherence to the cell line than did those of C. albicans serotype B, which lack antigen 6. The whole mannan from the C. albicans A parent inhibited the adherence of C. albicans A to epithelial cells dose dependently, whereas mannan from a mutant strains did not. Moreover, C. albicans A treated with MAb-6 or polyclonal factor 6 serum showed reduced adherence. A close correlation was found between adhesive ability and agglutinability with MAb-6 in the C. albicans A parent, the antigenic mutants, and their spontaneous revertants. These results suggest that so far as mannan adhesion is concerned, serotype A-specific determinants are largely involved in the mechanisms of adherence of C. albicans A to human buccal epithelial cells.