C-type lectin Langerin is a β-glucan receptor on human Langerhans cells that recognizes opportunistic and pathogenic fungi

Abstract

Langerhans cells (LCs) lining the stratified epithelia and mucosal tissues are the first antigen presenting cells to encounter invading pathogens, such as viruses, bacteria and fungi. Fungal infections form a health threat especially in immuno-compromised individuals. LCs express C-type lectin Langerin that has specificity for mannose, fucose and GlcNAc structures. Little is known about the role of human Langerin in fungal infections. Our data show that Langerin interacts with both mannan and β-glucan structures, common cell-wall carbohydrate structures of fungi. We have screened a large panel of fungi for recognition by human Langerin and, strikingly, we observed strong binding of Langerin to a variety of Candida and Saccharomyces species and Malassezia furfur, but very weak binding was observed to Cryptococcus gattii and Cryptococcus neoformans. Notably, Langerin is the primary fungal receptor on LCs, since the interaction of LCs with the different fungi was blocked by antibodies against Langerin. Langerin recognizes both mannose and β-glucans present on fungal cell walls and our data demonstrate that Langerin is the major fungal pathogen receptor on human LCs that recognizes pathogenic and commensal fungi. Together these data may provide more insight in the role of LCs in fungal infections.