title: Characterization of Cryptococcus neoformans capsular glucuronoxylomannan polysaccharide with monoclonal antibodies.
abstract: Mice were immunized with Cryptococcus neoformans serotype A capsular glucuronoxylomannan (GXM) conjugated to bovine serum albumin-adipic dihydrazide. Two splenocyte fusions yielded two monoclonal antibodies (MAbs) that were highly reactive in dot enzyme immunoassay, immunofluorescence, and sandwich enzyme immunoassay. The first MAb, BD-1 [immunoglobulin G1 (kappa) [IgG1(kappa)]], was GXM-A and GXM-D specific, whereas the second MAb, BA-4 (IgM), reacted with GXM-A and GXM-B. A third MAb, CD-6 [IgG1(kappa)], originated from mice immunized with O-deacetylated GXM-C-bovine serum albumin and reacted with GXMs of all four serotypes. Two of the MAbs (CD-6 and BD-1) were further characterized with chemically modified GXMs. Removal of glucuronosyl residues completely inhibited the binding of both MAbs, implicating (1----2)-beta-glucuronic acid as a key component of the epitope. Removal of (1----2)-beta-xylosyl residues decreased reactivity to an intermediate extent. O deacetylation led to a measurable decrease but had the least inhibitory effect of the three GXM derivatives tested. The combining site for these two MAbs appears to be a complex antigenic determinant involving more than one glycosidic residue.
authors.affiliation: Istituto di Microbiologia, Facolta di Medicina, Universita di Messina, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Todaro-Luck
authors.forename: E
authors.initials: E
authors.lastname: Reiss
authors.forename: R
authors.initials: R
authors.lastname: Cherniak
authors.forename: L
authors.initials: L
authors.lastname: Kaufman
mesh_terms: D000908:Antibodies, Fungal / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000946:Antigens, Fungal / Q000276:immunology*; D002240:Carbohydrate Sequence; D003454:Cryptococcus / Q000276:immunology*; D003455:Cryptococcus neoformans / Q000276:immunology*; D005455:Fluorescent Antibody Technique; D005965:Glucuronates; D007124:Immunoenzyme Techniques; D007700:Kinetics; D008351:Mannans / Q000276:immunology; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000276:immunology*; D012703:Serotyping; D013329:Structure-Activity Relationship
chemical_list: D000908:Antibodies, Fungal; D000911:Antibodies, Monoclonal; D000946:Antigens, Fungal; D005965:Glucuronates; D008351:Mannans; D011134:Polysaccharides