The Pattern Recognition Receptor Dectin-1: From Fungi to Mycobacteria

Abstract

The ability of the innate immune system to quickly recognize and respond to an invading pathogen is essential for controlling the infection. For this purpose, cells of the immune system express receptors which recognize evolutionarily conserved structures expressed by various pathogens but absent from host cells. In this review we focus on the non-classical C-type lectin receptors including Dectin-1 whose role has been extensively characterized in the recognition and response to fungal pathogens. Dectin-1 is a type II transmembrane protein which binds β-1,3 and β-1,6 glucans. It is expressed on most cells of the innate immune system and has been implicated in phagocytosis as well as killing of fungi by macrophages, neutrophils and dendritic cells. The Dectin-1 cytoplasmic tail contains an immunoreceptor tyrosine based activation motif (ITAM) that signals in part through the spleen tyrosine kinase and in collaboration with Toll-like receptors. Although the main research focus has been on Dectin-1's role as a fungal and yeast pathogen recognition receptor, more recent studies suggest that Dectin-1 may have a broader function in pathogen recognition including a role in directing a macrophage response to mycobacterial infections.

β-Glucans inhibit intracellular growth of Mycobacterium bovis BCG but not virulent Mycobacterium tuberculosis in human macrophages

“…β-glucan signaling through Dectin-1, which is at least partially dependent on TLR2, is known to induce spleen tyrosine kinase (Syk) and PKC leading to induction of NF-kB and a proinflammatory response [33]. In our model, Dectin-1 activation through this pathway is the most likely mechanism for the production of ROIs and pro-inflammatory cytokines in response to WGP (Figs.…”

Mycobacterium massiliense Induces Inflammatory Responses in Macrophages Through Toll-Like Receptor 2 and c-Jun N-Terminal Kinase

“…Our previous studies also showed that TLR2 and Dectin-1 are involved in the production of proinflammatory cytokines and chemokines to M. ulcerans or Mabc in human keratinocytes and murine macrophages, respectively [24, 37]. Dectin-1 is a type II transmembrane non-opsonic receptor and plays a key role in the binding and response to fungal-derived β-1,3 and β-1,6 glucan particles [38, 39]. It is expressed on most immune cells involved in innate immunity and plays an essential role in phagocytosis and antifungal activities in macrophages [38, 39].…”

Anticancer properties of low molecular weight oat beta-glucan – An in vitro study

“…This leads to various immune responses. Nevertheless, depending on the different sizes and branching patterns, ␤-glucans may have significantly variable immune potential [2,[18][19][20][21][22][23][24].…”