Ashley C, Morhart M, Rennie R, Ziola B
Department of Microbiology, University of Saskatchewan, Saskatoon, Canada.
J Med Microbiol. 1997 Sep;46(9):747-55. doi: 10.1099/00222615-46-9-747.
Candida albicans is the leading cause of invasive candidosis. As conventional tests do not reliably detect invasive infection, attention has turned to the detection of C. albicans antigens circulating in blood. As antigen tests for invasive candidosis could be improved if C. albicans antigens released upon phagocytosis were defined, this study was undertaken to characterise antigens released during the interaction of yeasts and human neutrophils in vitro. An enzyme immunoassay developed previously to detect what were believed to be predominantly C. albicans cytoplasmic antigens in patients with invasive candidosis was used to follow the neutrophil-mediated release of yeast antigens. Serum opsonisation enhanced antigen release, which was rapid and essentially complete by 1 h. When fresh C. albicans yeasts were added to medium from cultures of neutrophils plus yeasts or neutrophils plus latex beads, additional yeast antigens were released. Medium from neutrophils plus yeasts or from yeasts alone had similar immunoblot patterns with rabbit antibodies to a C. albicans cytoplasmic antigen preparation, with the reactive antigens generally being of higher mol. wt than the reactive antigens in the antigen mixture used for preparation of the antiserum. The two supernates also had similar immunoblot patterns with rabbit anti-C. albicans cell-wall mannan antibodies. These results suggest that yeast surface antigens are released quickly during phagocytosis by neutrophils. Detection of such yeast surface antigens, possibly together with selected yeast cytoplasmic antigens, should improve the sensitivity of C. albicans antigen assays.
白色念珠菌是侵袭性念珠菌病的主要病因。由于传统检测方法无法可靠地检测侵袭性感染，人们的注意力已转向检测血液中循环的白色念珠菌抗原。如果能够确定吞噬作用时释放的白色念珠菌抗原，侵袭性念珠菌病的抗原检测可能会得到改进，因此本研究旨在对酵母与人类中性粒细胞在体外相互作用过程中释放的抗原进行表征。先前开发的一种酶免疫测定法用于检测侵袭性念珠菌病患者中被认为主要是白色念珠菌细胞质抗原的物质，该方法用于跟踪中性粒细胞介导的酵母抗原释放。血清调理作用增强了抗原释放，抗原释放在1小时内迅速且基本完成。当将新鲜的白色念珠菌酵母添加到中性粒细胞加酵母或中性粒细胞加拉胶珠的培养物培养基中时，会释放出额外的酵母抗原。中性粒细胞加酵母或单独酵母的培养基与兔抗白色念珠菌细胞质抗原制剂抗体具有相似的免疫印迹模式，反应性抗原的分子量通常高于用于制备抗血清的抗原混合物中的反应性抗原。这两种上清液与兔抗白色念珠菌细胞壁甘露聚糖抗体也具有相似的免疫印迹模式。这些结果表明，酵母表面抗原在中性粒细胞吞噬过程中迅速释放。检测此类酵母表面抗原，可能连同选定的酵母细胞质抗原一起，应能提高白色念珠菌抗原检测的灵敏度。
