PolysacDB Glucurunoxylomannan 2607

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Contents

Carbohydrate Name

Glucurunoxylomannan

Carbohydrate Class

Miscellaneous

Source Microbe

Cryptococcus neoformans serotype A

Basic Structure

The capsular polysaccharide has a linear α-(1-->3)-linked mannose backbone that is substituted with nonreducing D-xylosyl and D-glucuronosyl acid groups. The mannose backbone is partially O-acetylated


Proposed functions

The capsular polysaccharide is an important virulence factor

Antigenic Nature used to produce antibodies

Glycoconjugates

Carrier Name

Tetanus toxoid

Conjugation Method

GXM was derivatized by the following two methods. (i) In method 1, ADH [adipic acid dihydrazide] was introduced into GXM by the activation of carboxyl groups with EDAC. GXM (5 mg/ml of 0.2 M NaCl) was derivatized with 0.5 M ADH and 0.1 M EDAC at pH 4.85 for 3.5 h at room temperature, using a pH Stat. After extensive dialysis against 0.2 M NaCl, the reaction mixture was passed through a 2B-CL Sepharose column (1.5 by 30 cm) equilibrated in 0.2 M NaCl. The fractions containing GXM were pooled and concentrated to the original volume. (ii) In method 2, ADH was introduced into GXM by the activation of hydroxyl groups with CNBr. GXM (5 mg/ml of 0.2 M NaCl) was activated with an equal weight of CNBr at pH 10.5 for 6 min at 4C, using a pH Stat. An equal volume of 0.5 M NaHCO3 (pH 8.5) containing 0.5 M ADH was added. The reaction mixture was tumbled at 3 to 8C for 18 to 20 h, dialyzed against 0.2 M NaCl, and passed through a 2B-CL Sepharose column (1.5 by 30 cm). The fractions containing GXM were pooled and concentrated to the original volume. The reaction mixture, containing equal concentrations (3.0 to 7.5 mg/ml) of GXM-AH (derivatized by either method) and TT or rEPA in 0.2 M NaCl, was brought to pH 5.6 with 0.05 N HCl, and 0.05 to 0.1 M EDAC was added; the pH was maintained at 5.6 in a pH Stat for 1 to 3 h at 4C. The reaction mixture was dialyzed against 0.2 M NaCl at 3 to 8C and passed through a Sepharose 2B-CL column (1.5 by 30 cm) equilibrated in 0.2 M NaCl. The void volume fractions containing the GXM and the protein were pooled and stored in 0.01% thimerosal at 3 to 8C

Antibodies

Mab 3E5

Antibody type and class

IgG3

Assay System

ELISA

Cross-reactivity

This antibody was cross-reactive to serotypes A,B,C and D

Proposed epitopes

N/A

Proposed Utility

could help in specific serotype identification

Weblink

PubMed

External Links