CANDIDA ALS GENE PRODUCTS AS TARGET IMMUNOGENS

虽然存在对念珠菌具有杀微生物作用的强效抗真菌药物，但即使采用目前可用的抗真菌治疗，念珠菌病的可归因死亡率约为38%。使用被动或主动免疫疗法对抗念珠菌是一种有希望的替代标准抗真菌治疗，其潜在的避免大量使用抗真菌药物相关的问题。我们的长期目标是确定显性念珠菌粘连，并将这些粘连作为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可能编码介导内皮细胞和上皮细胞粘附的粘附素。该基因是ALS基因家族的一员。到目前为止，已经确定了大约11个ALS基因家族成员。然而，这些基因中只有两个的序列被公布。这是我们的中心假设，ALS基因家族编码白色念珠菌的主要粘附。可能是不同的ALS蛋白介导了对不同宿主成分配体的粘附。我们建议系统地检查ALS基因家族的选定成员，以确定哪些成员编码介导白色念珠菌与内皮上皮和其他宿主成分结合的粘附素。这些信息将用于开发技术，通过使用被动或主动免疫来阻止生物体粘附宿主组织。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粘附，并确定它们与细胞表面的配体结合；iii)确定针对特定ALS蛋白的抗体是否阻断白色念珠菌对内皮细胞和上皮细胞的粘附，以及体外选定的宿主成分；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源性弥散性念珠菌感染。我们将确定粘附作为主动和被动免疫策略的目标。这些黏附素本身是免疫治疗的极具吸引力的靶标，具有与真菌学研究单位其他项目确定的靶标结合使用的潜力。

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.