Virulence factors of agents of particularly dangerous mycoses

Polovetz N.V., Murugova A.A., Lipnitsky A.V.

Volgograd Plague Control Research Institute, Volgograd, Russia

This review aims to summarize current information on the virulence of dimorphic fungi, causative agents of invasive mycoses (coccidioidomycosis, histoplasmosis, blastomycosis, paracoccidioidomycosis). These fungi naturally occur as mycelial saprophytes. Following inhalation, body temperature triggers the mechanism of conidia (spores) and mycelial fragment differentiation into a parasitic yeast phase. This morphologic switch leads to the expression of virulence factors, which enable adhesion of the fungi to host tissues, growth and proliferation in macrophages, cytokine response modulation and decrease the effectiveness of cellular immunity. Virulence factors of dimorphic pathogenic fungi are defined as essential for their survival and development in a mammalian host, but not in their natural environment or in vitro. The identification of genes associated with virulence factors is primarily carried out using molecular techniques. The discovery and characterization of virulence factors drive the development of new diagnostic methods, antifungal drugs and experimental vaccines for invasive mycoses.