Differential Recognition of , , and by Human Monocyte-Derived Macrophages and Dendritic Cells

Background: Sporotrichosis is a mycosis frequently caused by , and . The cell wall is a species-specific fungal structure with a direct role in activating the host's immune response. The current knowledge about anti- immunity comes from studies using or and murine cells. Macrophages and dendritic cells detect and eliminate pathogens, and although the function of these cells links innate with adaptive immunity, little is known about their interaction with spp.

Methods: , and conidia or yeast-like cells were co-incubated with human monocyte-derived macrophages or dendritic cells, and the phagocytosis and cytokine stimulation were assessed. These interactions were also performed in the presence of specific blocking agents of immune receptors or fungal cells with altered walls to analyze the contribution of these molecules to the immune cell-fungus interaction.

Results: Both types of immune cells phagocytosed conidia and yeast-like cells to a greater extent, followed by and . Furthermore, when the wall internal components were exposed, the phagocytosis level increased for and , in contrast to . Thus, the cell wall components have different functions during the interaction with macrophages and dendritic cells. stimulated an increased proinflammatory response when compared to the other species. In macrophages, this was a dectin-1-, mannose receptor-, and TLR2-dependent response, but dectin-1- and TLR2-dependent stimulation in dendritic cells. For and , cytokine production was dependent on the activation of TLR4, CR3, and DC-SIGN.

Conclusion: The results of this study indicate that these species are recognized by immune cells differently and that this may depend on both the structure and cell wall organization of the different morphologies.