Caspofungin-induced β-(1,3)-glucan unmasking is associated with enhanced innate immune clearance of Candida (Candidozyma) auris

ABSTRACT Candida auris is an emerging multidrug-resistant fungal pathogen that avoids early host immune detection by masking immunostimulatory β-(1,3)-glucan beneath a dense outer mannan layer. Whether caspofungin-induced cell wall remodeling can increase β-(1,3)-glucan exposure and alter innate immune interactions in C. auris remains poorly understood. In this study, we investigate how sublethal concentrations of caspofungin induce cell wall remodeling and modulate innate immune responses. Sublethal caspofungin concentrations were used to maintain normal growth kinetics while allowing cell wall remodeling. Caspofungin treatment increased β-(1,3)-glucan surface exposure across Candida strains, with the strongest response observed in C. auris strain 1100. This increase was supported by fluorescence microscopy, Cy3-positive cell quantification, and ImageJ-based analysis of fluorescence intensity and stained surface area. Scanning electron microscopy showed surface changes consistent with caspofungin-treated cell wall remodeling. Caspofungin-treated Candida cells exhibited enhanced uptake by RAW 264.7 macrophages and increased macrophage-mediated clearance at early and intermediate time points. In C. auris , this increased clearance persisted over 24 h, whereas the effect diminished in C. albicans , consistent with species-specific differences in macrophage interaction and intracellular survival. Finally, in the Galleria mellonella infection model, larvae infected with caspofungin-pretreated cells showed improved survival and reduced fungal burden compared with larvae infected with untreated controls. Together, these findings show that sublethal caspofungin exposure is associated with increased β-(1,3)-glucan exposure, cell wall remodeling, and enhanced innate immune clearance of C. auris . These results support fungal cell wall remodeling as a potential adjunct strategy to improve host-mediated control of multidrug-resistant Candida infections. IMPORTANCE C. auris is a dangerous fungal pathogen that is difficult to treat and can evade the body’s immune defenses. One reason for its success is its ability to hide key cell wall components that immune cells normally recognize. In this study, we show that low, non-lethal levels of the antifungal drug caspofungin can alter the fungal cell wall in a way that exposes these hidden immune signals. This exposure is associated with improved recognition, engulfment, and killing of C. auris by immune cells. Using imaging, immune cell assays, and an infection model, we show that caspofungin-induced cell wall remodeling is associated with enhanced immune clearance and reduced fungal burden. These findings reveal an additional benefit of echinocandin treatment and suggest that antifungal drugs may help the immune system fight infection, even at doses that do not directly kill the fungus.