Fig. 7: Proposed model for the role of C. auris outer mannan layer in dampening innate immune responses.

C. auris has a structurally distinct mannan layer at the cell wall surface that shields the inner β-glucan, reducing recognition by the receptors of innate immune cells such as macrophages. Reduced macrophage activation leads to successful colonization and proliferation of C. auris by avoiding being cleared by immune cells such as neutrophils. In contrast, the disrupted mannan layer in C. auris leads to exposure to β-glucan, which can be recognized by the surface receptors of macrophages. The host-pathogen interaction results in the activation of MAPK signaling pathway and release of pro-inflammatory cytokines and chemokines, which finally leads to activation and recruitment of neutrophils and triggers the clearance of invading C. auris. Note: Inset represents an enlarged area of the three layers of C. auris cell wall, which is organized in an inner skeletal layer comprising chitin, β-glucan, and an outermost layer dominated by highly glycosylated mannoproteins.