CANDIDA ALS GENE PRODUCTS AS TARGET IMMUNOGENS

虽然存在有效的抗真菌药物对念珠菌具有杀菌作用，但即使使用现有的抗真菌治疗，念珠菌血症的可归因性死亡率也约为38%。针对念珠菌的被动或主动免疫治疗是标准抗真菌治疗的一种有前途的替代方案，因为它具有避免大量使用抗真菌药物所带来的问题。我们的长期目标是确定主要的念珠菌粘连，并将这些粘连用作严重念珠菌感染的主动或被动免疫治疗的靶点。在目前的项目期间，我们确定白色念珠菌基因ALS1可能编码一种粘附素，介导与内皮细胞和上皮细胞的附着。该基因属于肌萎缩侧索硬化症基因家族。到目前为止，大约有11个ALS基因家族成员已经被鉴定出来。然而，这些基因中只有两个的序列已经公布。我们的中心假设是ALS基因家族编码了白色念珠菌的主要黏附。这可能是不同的ALS蛋白介导与不同的宿主组成配体的黏附。我们建议系统地研究ALS基因家族中选定的成员，以确定它们中的哪些编码介导白色念珠菌与内皮细胞结合的粘附素以及其他宿主成分。这些信息将被用来开发技术，通过使用被动或主动免疫来阻止有机体与宿主组织的粘连。本项目的具体目标是：i)获得ALS6和ALS94-98的全长序列；ii)确定上述ALS基因是否编码与内皮细胞、上皮细胞和选定的其他宿主成分的黏附，并确定它们结合到的细胞表面的配体；iii)确定针对特定ALS蛋白的抗体是否能在体外阻止白念珠菌与内皮细胞和上皮细胞的黏附，以及是否能阻止选定的宿主成分；以及iv)确定针对特定ALS蛋白的抗体是否能保护小鼠免受粘膜和血液播散性念珠菌感染。我们将把粘附性确定为主动和被动免疫战略的目标。这些粘附素本身就是非常有吸引力的免疫治疗靶点，有可能与真菌学研究单位其他项目确定的靶点结合使用。

While potent antifungal agents exist that are microbicidal for Candida, the attributable mortality of candidemia is approximately 38%, even with currently available antifungal therapy. The use of either passive or active immuno-therapy against Candida is a promising alternative to standard anti- fungal therapy of its potential to avoid the problems association with heavy use of antifungal agents. Our long range goal is to identify dominant candidal adhesions and use these adhesions as targets for active or passive immunotherapy for serious candidal infections. During the current project period, we determined that the C. albicans gene, ALS1, likely encodes an adhesin that mediated attachment to endothelial and epithelial cells. This gene is a member of the ALS gene family. To date, approximately 11 members of the ALS gene family have been identified. However, the sequence of only two of these genes have been published. It is our central hypothesis that the ALS gene family encodes the major adhesion of C. albicans. It is likely that the different ALS proteins mediate adherence to different host constituent ligands. We propose to systematically examine selected members of the ALS gene family to determine which of them encode adhesins that mediate the binding of C. albicans to endothelium epithelium, and other host constituents. This information will be used to develop techniques to block the adherence of the organism to host tissues by using either passive or active immunization. The Specific Aims for this project are to i) obtain thje full-length sequence of ALS6 and ALS94-98; ii) determine if the above ALS genes encode adhesions to endothelial cells, epithelial cells and selected other host constituents, and determine the ligands on the cell surface to which they bind; iii) determine if antibodies against specific ALS proteins block the adherence of C. albicans to endothelial and epithelial cells, and the selected host constituents in vitro; and iv) determine if antibodies against specific ALS proteins protect mice from mucosal and hematogenously disseminated candidal infections. We will identify adhesion as targets for active and passive immunization strategies. These adhesins are highly attractive targets for immunotherapy by themselves, have the potential to be used in combination with the targets identified by other projects in the Mycology Research Unit.