title: Cryptococcus neoformans galactoxylomannan is a potent negative immunomodulator, inspiring new approaches in anti-inflammatory immunotherapy.
abstract: Cryptococcus neoformans is an opportunistic fungal pathogen responsible for life-threatening infections in immunocompromised individuals and occasionally in those with no known immune impairment. The fungus is endowed with several virulence factors, including capsular polysaccharides that play a key role in virulence. The capsule is composed of 90-95% glucuronoxylomannan (GXM), 5-8% galactoxylomannan (GalXM) and <1% mannoproteins. Capsular polysaccharides are shed into tissue where they produce many deleterious effects. Since GalXM has a smaller molecular mass, the molar concentration of GalXM in polysaccharide that is shed could exceed that of GXM in C. neoformans exopolysaccharides. Moreover, GalXM exhibits a number of unusual biologic properties both in vitro and in vivo. Here, we summarize the principal immunomodulatory effects of GalXM described during the last 20 years, particularly the mechanisms leading to induction of apoptosis in T lymphocytes, B lymphocytes and macrophages. Since the capacity of GalXM to induce widespread immune suppression is believed to contribute to the virulence of C. neoformans, this property might be exploited therapeutically to dampen the aberrant activation of immune cells during autoimmune disorders.
authors.affiliation: Microbiology Section, Department of Experimental Medicine & Biochemical Sciences, University of Perugia, Via del Giochetto, 06126 Perugia, Italy. vecchiar@unipg.it
authors.forename: Anna
authors.initials: A
authors.lastname: Vecchiarelli
authors.forename: Eva
authors.initials: E
authors.lastname: Pericolini
authors.forename: Elena
authors.initials: E
authors.lastname: Gabrielli
authors.forename: Siu-Kei
authors.initials: SK
authors.lastname: Chow
authors.forename: Francesco
authors.initials: F
authors.lastname: Bistoni
authors.forename: Elio
authors.initials: E
authors.lastname: Cenci
authors.forename: Arturo
authors.initials: A
authors.lastname: Casadevall
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology; D001327:Autoimmune Diseases / Q000188:drug therapy* / Q000276:immunology*; D001402:B-Lymphocytes / Q000187:drug effects; D003455:Cryptococcus neoformans / Q000276:immunology*; D006801:Humans; D007165:Immunosuppression Therapy; D007167:Immunotherapy; D008264:Macrophages / Q000187:drug effects; D011134:Polysaccharides / Q000494:pharmacology / Q000627:therapeutic use*; D013601:T-Lymphocytes / Q000187:drug effects
chemical_list: D000893:Anti-Inflammatory Agents; D011134:Polysaccharides; C043689:galactoxylomannan