Immunology of fungal infections

Host resistance in fungal infections is dependent on a variety of factors and even if one or more may be predominant, a combination of several defense mechanisms, with an active interplay between innate and adaptive immunity, is usually required for an effective antifungal response. In experimental disseminated and mucosal fungal infections it has been demonstrated that T helper cells play a pivotal role in regulating immune responses to fungi by secreting cytokines that modulate the development and activity of immune effecters. On the other hand, cells of the innate immune system regulate the T helper cell development through costimulation, by secreting directive cytokines, and by reducing the fungal load in the course of infection. Recent studies in genetically modified mice further add to the complex cross-regulatory mechanisms operating between innate and adaptive antifungal immunity, which were previously unappreciated.