title: Secretion of TNF-alpha by alveolar macrophages in response to Candida albicans mannan.
abstract: Resident alveolar macrophages (AM phi) were tested for their ability to respond to Candida albicans mannan. AM phi were found to produce tumor necrosis factor alpha (TNF-alpha) in vitro in response to mannan stimulation. TNF-alpha secretion was measured using ELISA and L929B cellular cytotoxicity assays. Cytotoxicity was neutralized in parallel L929B cell cultures by the addition of rabbit anti-TNF-alpha antibody. Mannan preparations were found to be free of contaminating LPS by Limulus assay. When AM phi were cultivated for 18 h at 37 degrees C, 67 micrograms of mannan stimulated the secretion of approximately 207 U/ml of TNF-alpha. By comparison, AM phi treated with 6.7 micrograms of LPS secreted approximately 257 U/ml of TNF-alpha. Optimal TNF-alpha production occurred between 9 and 18 h after mannan stimulation. Disparate mechanisms for stimulation of TNF-alpha secretion were suggested by differential sugar blockade of LPS- and mannan-induced TNF-alpha secretion. The addition of 2% D-mannose or 2% alpha-methyl-D-mannoside to AM phi cultures blocked mannan- but not LPS-stimulated TNF-alpha secretion. Furthermore, the addition of rabbit anti-mannan antibody to mannan-coated plastic culture dishes prevented TNF-alpha secretion by the mannan-sensitive RAW 264.7 cell line. Moreover, the data suggest that C. albicans mannan stimulated AM phi to secrete TNF-alpha by an LPS-independent receptor mechanism which may also function as a mannose receptor.
authors.affiliation: Division of Biomedical Science, Mercer University School of Medicine, Macon, Georgia 31207.
authors.forename: R E
authors.initials: RE
authors.lastname: Garner
authors.forename: K
authors.initials: K
authors.lastname: Rubanowice
authors.forename: R T
authors.initials: RT
authors.lastname: Sawyer
authors.forename: J A
authors.initials: JA
authors.lastname: Hudson
mesh_terms: D000818:Animals; D001681:Biological Assay; D002175:Candida; D002176:Candida albicans / Q000254:growth & development / Q000378:metabolism; D002478:Cells, Cultured; D007700:Kinetics; D008070:Lipopolysaccharides / Q000633:toxicity; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008351:Mannans / Q000096:biosynthesis / Q000302:isolation & purification / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008811:Mice, Inbred DBA; D012441:Saccharomyces cerevisiae; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D008351:Mannans; D014409:Tumor Necrosis Factor-alpha