ACTIVATION OF THE COMPLEMENT-SYSTEM BY PATHOGENIC FUNGI

Fungi have been studied as prototype activators of tire complement cas cade since the early 1900s. More recently attention has focused on the role of the complement system in the pathogenesis of fungal infection s. The interactions of Cryptococcus neoformans and Candida albicans wi th the complement system are the most widely characterized; however, a ll pathogenic fungi examined to date have the ability to initiate the complement cascade. The molecular mechanisms for initiation and regula tion of the complement cascade differ from one fungus to another, most likely reflecting differences in the structure of the outer layers of the cell wall. The molecular bases for such differences remain to be identified. Studies of mycoses in experimental animals with induced or congenital deficiencies in the complement system demonstrate that com plement is an important inmate system for control of fungal infection. Contributions to host resistance include opsonization and generation of inflammatory mediators. Inflammation induced by chemotactic product s of the complement system may contribute to tile pathogenesis of some fungal infections.