CD is associated with a microbiotic dysbiosis and the development of antibodies against members of the microbiota [161]. Hedgehog antagonist This includes anti-S. cerevisiae antibodies, which have been shown to be reactive to an in vivo expressed epitope on Candida species, as well as baker’s yeast [149]. Defects in the C-type lectin, β-glucan receptor dectin-1 — which plays a fundamental role in antifungal immunity by β-glucan yeast wall component recognition [162] and which deficiency in humans causes fungal

infection susceptibility [50] — confer increased susceptibility to chemically induced colitis, disease that could be exacerbated by repeated oral delivery of C. tropicalis [160]. This was consistent with the report that C. albicans could also exacerbate DSS-induced colitis [163] and that an indigenous Candida population could drive disease. Similarly, lung responses generated via the β-glucan receptor dectin-1 are required for lung defense during acute, invasive A. fumigatus

infection through Barasertib mouse IL-22 production [164]. Unexpectedly, lung responses generated via dectin-1, in an allergic mouse model of chronic lung exposure to live A. fumigatus conidia, lead to the induction of multiple proallergic (Muc5ac, Clca3, CCL17, CCL22, and IL-33) and proinflammatory (IL-1β and CXCL1) mediators that compromised lung function [165]. Assessment of cytokine responses demonstrated that purified lung CD4+ T cells produced IL-4, IL-13, IFN-γ, and IL-17A, but not IL-22, in a dectin-1-dependent manner [108]. Overall we can conclude that dectin-1 contributes to both protection and gut and lung inflammation and immunopathology associated with persistent fungal exposure,

via mechanisms that involve constant integration of messages derived from different locations in the body. Recent Rolziracetam culture-independent surveys of eukaryotic communities reveal that, similar to bacteria, commensal fungi are an essential part of human ecosystems. The role of the mycobiota in the maintenance of health can be understood only using a “systems level” integrated ecological approach, as opposed to an approach focused on specific, disease-causing taxa. Strain-specific traits, such as differences in cell wall composition among isolates from the same fungal species, may prove to be as important as differences in mycobiota species composition to maintain the correct immune homeostasis [134, 166]. Previous results demonstrating a switch from a Th1-Treg response to a Th17 response following exposure to different life stages of the same strain of S. cerevisiae [167], as well as the results showing the Candida GUT phenotype shift [155] are clear examples of the need to functionally analyze the mycobiota at the strain level, rather than simply counting its parts at the species level.