Candida albicans cell-type switching and functional plasticity in the mammalian host

Abstract

In this Review, Noble and colleagues discuss the characteristics of the classic cell types ofCandida albicans— yeast, hyphae, pseudohyphae and chlamydospores — as well as newly identified yeast-like morphotypes, including grey and gastrointestinally induced transition (GUT) cell types, and highlight emerging knowledge about their associations with different host niches and propensities towards virulence versus commensalism. Candida albicans is a ubiquitous commensal of the mammalian microbiome and the most prevalent fungal pathogen of humans. A cell-type transition between yeast and hyphal morphologies in C. albicans was thought to underlie much of the variation in virulence observed in different host tissues. However, novel yeast-like cell morphotypes, including opaque(a/α), grey and gastrointestinally induced transition (GUT) cell types, were recently reported that exhibit marked differences in vitro and in animal models of commensalism and disease. In this Review, we explore the characteristics of the classic cell types — yeast, hyphae, pseudohyphae and chlamydospores — as well as the newly identified yeast-like morphotypes. We highlight emerging knowledge about the associations of these different morphotypes with different host niches and virulence potential, as well as the environmental cues and signalling pathways that are involved in the morphological transitions.