Bikandi J, Moragues M D, Quindós G, Polonelli L, Pontón J
Departamento de Immunologia, Microbiología y Parasitologia, Facultad de Medicina y Odontología, Universidad del País Vasco, Vizcaya, Spain.
J Dent Res. 2000 Jun;79(6):1439-42. doi: 10.1177/00220345000790061401.
Salivary secretory IgA reacts with a group of heat-shock mannoproteins preferentially expressed on Candida albicans yeast cells and germ tubes grown at 37 degrees C. Since other environmental factors can also modulate the expression of those antigens, we have investigated the influence of the pH of the culture medium on the expression of the antigens reacting with human salivary IgA by C. albicans. By indirect immunofluorescence, yeast cells grown in Sabouraud glucose broth at 37 degrees C showed a statistically significant increase in reactivity with salivary IgA (p < 0.0001) when compared with cells grown at 25 degrees C at the 4 pH values studied (3.3, 5.9, 7.5, and 9.5), the highest reactivity and the major heat-shock effect being observed at pH 5.9. The decrease in reactivity with salivary IgA observed in C. albicans cells grown at pH values of 3.3 and 9.5 was confirmed by Western blotting. Salivary IgA reacted with polydispersed materials from the cell walls of molecular masses > 55 kDa, which were more expressed at neutral pH than at acidic or alkaline pH values. A similar reactivity was observed when the antigenic extracts were stained with an antiserum directed against oligosaccharides present in antigen 6 of C. albicans serotype A. The differences in reactivity presented by salivary IgA may be related to a decrease in the expression of polysaccharides present on the surfaces of the yeast cells of C. albicans grown at acidic or alkaline pH values. The low reactivity of salivary IgA with C. albicans cells grown at acidic pH values may help to explain the association between acidic saliva and the carriage of Candida in the oral cavity, as well as with oral candidiasis.
唾液分泌型IgA与一组热休克甘露糖蛋白发生反应，这些蛋白在白色念珠菌酵母细胞和在37℃培养的芽管上优先表达。由于其他环境因素也可调节这些抗原的表达，我们研究了培养基pH值对白色念珠菌与人类唾液IgA反应的抗原表达的影响。通过间接免疫荧光法，在研究的4个pH值（3.3、5.9、7.5和9.5）下，与在25℃培养的细胞相比，在37℃萨布罗葡萄糖肉汤中培养的酵母细胞与唾液IgA的反应性有统计学显著增加（p<0.0001），在pH 5.9时观察到最高反应性和主要热休克效应。在pH 3.3和9.5培养的白色念珠菌细胞中观察到的与唾液IgA反应性的降低通过蛋白质印迹法得到证实。唾液IgA与分子量>55 kDa的细胞壁多分散物质发生反应，这些物质在中性pH下比在酸性或碱性pH值下表达更多。当抗原提取物用针对白色念珠菌A血清型抗原6中存在的寡糖的抗血清染色时，观察到类似的反应性。唾液IgA呈现的反应性差异可能与在酸性或碱性pH值下生长的白色念珠菌酵母细胞表面存在的多糖表达减少有关。唾液IgA与在酸性pH值下生长的白色念珠菌细胞的低反应性可能有助于解释酸性唾液与口腔念珠菌携带以及口腔念珠菌病之间的关联。
