Journal of Glycobiology
Open Access
ISSN: 2168-958X
+44 1478 350008
ISSN: 2168-958X
+44 1478 350008
Sachiko Sato, Brendan Snarr, Guillaume St Pierre, Yukiko Sato, Melanie Lehoux and Donald C Sheppard
Laval University, Canada
McGill University Health Centre, Canada
Posters & Accepted Abstracts: J Glycobiol
Invasive fungal infections are one of the most important causes of infectious mortality and are responsible for 1.5 million deaths per year. Despite this fact, fungal pulmonary infections remain under-studied with few anti-fungal drugs. Majority of the invasive infections are caused by opportunistic mycoses, such as Aspergillus fumigatus, and the current increase in the incidence is due to escalations in infections associated with invasive interventions for cancer treatment or organ transplantation. In healthy individuals, inhaled fungi are removed by mucociliary clearance and neutralized by phagocytes in the lungs, following recognition of fungal polysaccharides by pattern recognition receptors. Especially, recognition of �²-glucan by dectin-1 is critical for the induction of anti-fungal defense. �²-Glucan, however, is largely buried within the glycocalyx and is masked by outer cell wall polysaccharides. It has therefore been hypothesized that immune recognition of outer polysaccharides by other host lectins precedes, and facilitates the recognition of �²-glucan. We recently found that pulmonary infection with A. fumigatus rapidly induces massive accumulation of a host lectin, galectin-3, at the site of infection. Galectin-3 has been previously characterized as a soluble mammalian �²-galactoside binding lectin. Interestingly, this �²-galactoside binding lectin recognizes A. fumigatus-unique galactosaminogalactan (GAG), which conceals �²-glucans on the fungal surface, despite the fact that GAG does not contain any �²-galactosides, but rather a polymer of �±-galactose and �±-(N-acetyl)galactosamine moieties. Galectin-3 deficient mice displayed increased susceptibility to the infection than wild type. Collectively, these data suggest that endogeneous galectin-3 plays a critical role as a non-canonical PRR and mediates protective immune responses.