Studies on the Candida albicans-tissues interaction in disseminated candidiasis

传染病微生物通常以特定的宿主组织为目标，而不是随机入侵器官。弥散性念珠菌病的发病机制的第一步是真菌与宿主组织的粘连。我们采用了一种体外试验来研究白色念珠菌从血液扩散到内脏器官的机制。白念珠菌与小鼠脾的边缘带巨噬细胞特异性结合。白念珠菌细胞壁磷甘露糖苷蛋白复合体(PMPC)的酸性稳定部分均匀地显示在白色念珠菌酵母和菌丝体的细胞表面，PMPC酸性稳定部分的甘露聚糖核心和低聚甘露糖基侧链是该真菌在体外与边缘带巨噬细胞黏附的原因。酵母细胞在体内依赖PMPC与脾边缘带的黏附机制与体外实验中的黏附机制相似，这是因为边缘区巨噬细胞表达甘露糖样受体。最后，我们从J774.E细胞系获得的结果表明，脾边缘区和淋巴组织中的巨噬细胞表达一种MR黏附系统，该黏附系统唯一地结合白色念珠菌酵母细胞。这种相互作用可能在播散性念珠菌病的发病机制中起重要作用。

Infectious disease microorganisms usually target specific host tissues rather than invading organs randomly. An initial step in the pathogenesis of a dissiminated candidiasis is adherence of the fungus to the host tissue. We have adapted an ex vivo assay to study the mechanisms of Candida albicans dissemination from the blood into internal organs. C.albicans binds specifically to the marginal zone macmrophages of mouse spleen. The acid-stable part of C.albicans cell wall phosphomannoprotein complex (PMPC) displayed homogenously on the C.albicans yeast and hyphal form cell surface, and both mannan core and oligomannosyl side chains of the acid-stable part of PMPC are responsible for the adherence of this fungus to the marginal zone macrophages ex vivo. The in vivo PMPC-dependent adherence of yeast cells to the splenic marginal zone occurs by a similar mechanism as adherence in the ex vivo assay, which is because of a mannose-like receptor expressed by mmarginal zone macrophages. Finally, our results obtained from J774.E cell line suggest that macrophages in the splenic marginal zone and lymph node tissues express a MR adhesion system that uniquely binds C.albicans yeast cells. This interaction may be important in the pathogenesis of disseminated candidiasis.