PolysacDB Glucurunoxylomannan 1028
From DrugPedia: A Wikipedia for Drug discovery
Carbohydrate Name
Glucurunoxylomannan
Carbohydrate Class
Miscellaneous
Source Microbe
Cryptococcus neoformans
Basic Structure
The GXM is a high-molecular-weight linear (1-->3)-α-D-mannan substituted with single (1-->2)-β-xylosyl and (1-->2)-β-glucuronosyl residues. 0 acetylation occurs on the C-6 of about half of the mannose residues. The molar ratio of xylose-mannose-glucuronic acid is 2:3:1 for serotype A
Proposed functions
The capsular glucuronoxylomannan (GXM) of C. neoformans is anantiphagocytic and tolerogenic polysaccharide and potentiates virulence
Antigenic Nature used to produce antibodies
Glycoconjugates
Carrier Name
Bovine serum albumin
Conjugation Method
GXM (100 mg) was suspended in acetone, and 75 ul of pyridine was added. Tresyl chloride (50 ,ul) was added and stirred for 10 min. The activated GXM was washed with ethanol containing 5 mM HCI, washed with absolute ethanol, and dried in vacuo. Activated GXM (46 mg) was dissolved in 1.5 ml of 0.2 M NaH2PO4 buffer (pH 7.5) (coupling buffer), and BSA-AH was added (25 mg in 0.5 ml of the same buffer). The reaction was stirred overnight at 24C. The precipitate was removed by centrifugation, and the supernatant was applied to a column (90 by 2.5 cm) of Sepharose CL-6B equilibrated with 0.05 M Tris hydrochloride-0.1 M NaCl buffer (pH 7.6). The flow rate was 35 ml/h. Fractions containing carbohydrate and protein appeared in the void volume. They were pooled, dialyzed, and lyophilized (yield, 33 mg). The conjugate was then rechromatographed [yield, 17 mg]
Antibodies
Mab BD1
Antibody type and class
IgG1
Assay System
Indirect immunofluorescence
Cross-reactivity
This antibody cross-reacted with 2 serotypes- A and D. BD-1 also showed some cross-reactions at a low dilution with B. dermatitidis and H. capsulatum and C. terreus
Proposed epitopes
Glucuronic acid was proposed to be the important constituent of the epitope. However the epitope also probably contained xylose and was influencedto a minor extent by the presence of O-acetyl groups
Proposed Utility
MAb against an epitope shared by all four serotypes may have value for the detection of cryptococcal antigens in body fluids. This antibody also has potent opsonic activity
