Mycobiota–host immune interactions in IBD: coming out of the shadows

2021 has been a productive year for fungal research. Key studies focused on intestinal inflammation and inflammatory bowel disease highlight antibody-mediated immunity in control of fungal commensalism, commensal and dietary fungi in intestinal inflammation and wound healing, and the therapeutic potential of transgenic yeast engineered to sense and target factors during intestinal inflammation. Key advances Mycobiota-induced antibodies influence systemic antifungal immunity 5 and fungal commensalism in the gut by targeting Candida albicans adhesins 6 (Als3) and secreted virulence factors 7 (candidalysin and Sap6). Targeting Als3 influenced the severity of colitis in mice 6 , whereas secretory IgA antibodies to candidalysin and Sap6 are dysregulated in Crohn’s disease 7 . Food-associated Candida species such as Debaryomyces hansenii can influence intestinal physiology 1 . D. hansenii found in mouse and human intestinal wounds prevent healing by turning protective macrophages into CCL5-producing perpetuators of tissue recovery 1 . Transgenic Saccharomyces cerevisiae were engineered to sense and respond to intestinal extracellular ATP and suppress intestinal inflammation in mouse models 9 , providing a powerful example of mycobiota-centred future therapeutics.