Additionally, structural analysis of mannan was further investigated (Fig
August 16, 2021
Additionally, structural analysis of mannan was further investigated (Fig.?S11). infections. Over recent decades, the incidence of candidiasis worldwide has shifted from to non-species (NACs) due to the evolution of resistance to anti-fungal medications1,2. is an emerging Penciclovir nosocomial fungal pathogen primarily found in patients with hematologic malignancies undergoing bone marrow transplantation3C6. In addition, the frequency of in candiduria and mucocutaneous candidiasis in diabetic patients has significantly risen recently7C9. The prevalence of has increased since it became a multidrug-resistant pathogen because of its intrinsic fluconazole resistance and decreased susceptibility to flucytosine, amphotericin B and echinocandins2,5,10C13. Furthermore, this has made infections difficult to treat and led to a high mortality rate2,14. Despite its increasing importance, little is known regarding the immune system response to cell walls play a pivotal role in triggering host immune responses, which in turn either protect against the fungal contamination or facilitate fungal immune evasion15C17. Mannans Penciclovir are mannose polymers located in the outermost a part of cell walls; therefore, Rabbit polyclonal to OAT they may be the first component to interact with the immune system. As cell wall mannans are complex structures, elaborate immune mechanisms have evolved16,17. While studies have shown that mannans can induce anti-fungal protective immunity18C20, other reports have revealed that mannans are a significant virulence factor associated with the severity and pathogenesis of infections21,22. Furthermore, high levels of mannans can be detected in the blood of invasive candidiasis patients and it has been related to disease onset and progression23,24. Dendritic cells (DCs) are potent antigen-presenting cells that reside in both lymphoid and non-lymphoid tissues and act as sentinels of the immune system. Interactions between invading pathogens and DCs via pathogen-associated molecular patterns (PAMPs) pattern-recognition receptors (PRRs) provide the foundation that triggers adaptive immune responses16,25. DCs abundantly express C-type lectin receptors (CLRs) and Toll-like receptors (TLRs), many of which can bind to mannans. The activation of Penciclovir different types of mannan-specific receptors leads to differential DC activation that subsequently dictates distinct T cell responses16,17,25. Recognition of mannans by CLRs and TLRs on DCs depends on mannan structure and mannosyl composition. In Penciclovir general, N-linked mannans are recognized by dectin-2, mincle, mannose receptor (MR or CD206) and DC-SIGN (CD209), while O-linked mannans are recognized by TLR-417. Furthermore, the -mannans preferentially engage with dectin-2 and dectin-320,26, while the -mannans specifically ligate to galectin-3, which mediates TLR-2 activation27,28. The interactions of mannans with several CLRs expressed on DCs induce Syk activation, which consequently mediates innate resistance to systemic fungal contamination and orchestrates the Th17 response19,29,30. However, some mannose residues mediates signal transduction via the TLR/MyD88Cdependent pathway, and participates in host defense against contamination31C33. To date, the role of mannan in DC immunity is not clear. Since mannan structures and mannosyl composition in the cell wall of species are highly diverse, we compared the effects of cell wall mannans extracted from and on DCs, and T cell responses. Results mannan induced DC maturation and brought on massive productions of Penciclovir pro-inflammatory cytokines To evaluate whether cell wall mannans extracted from four distinct species differentially affected the phenotypic maturation of DCs, BMDCs were stimulated with various concentrations of mannans and subsequently characterized by flow cytometric analyses of the maturation markers CD40, CD80, CD86 and MHC class II (Figs.?1, S1 and S2). The DC population was first identified by gating a DC marker, CD11c (Fig.?S1A), and geometric MFI of the maturation markers was assessed using a histogram analysis (Figs.?1A and S1B). BMDCs stimulated with and mannans did not undergo maturation compared to the unfavorable control, whereas those stimulated with and mannans were potently activated. mannan upregulated expression of CD40, CD86 and MHC class II on BMDCs, and induced the highest levels of CD40, especially at the highest mannan concentration. Although, mannan also.