Immunity to Candida albicans: Th1, Th2 cells and beyond.

Resistance to Candida albicans infection in mice results from the development of T helper (Th) type 1 cell responses. Cytokines produced by Th1 cells activate macrophages and neutrophils to a candidacidal state. The development of Th2 responses underlines susceptibility to infection, because cytokines produced by Th2 cells inhibit Th1 development and deactivate phagocytic effector cells. With the recognition of the reciprocal influences between innate and adaptive Th immunity, it appears that the coordinated action of these two lines of immune defense is required to efficiently oppose the infectivity of the fungus and to determine its lifelong commensalism at the mucosal level.