Characterization of Cryptococcus neoformans capsular glucuronoxylomannan polysaccharide with monoclonal antibodies

Infect Immun. 1989 Dec;57(12):3882-7. doi: 10.1128/iai.57.12.3882-3887.1989.

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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Fungal / immunology*
  • Antibodies, Monoclonal / immunology*
  • Antigens, Fungal / immunology*
  • Carbohydrate Sequence
  • Cryptococcus / immunology*
  • Cryptococcus neoformans / immunology*
  • Fluorescent Antibody Technique
  • Glucuronates
  • Immunoenzyme Techniques
  • Kinetics
  • Mannans / immunology
  • Molecular Sequence Data
  • Polysaccharides / immunology*
  • Serotyping
  • Structure-Activity Relationship

Substances

  • Antibodies, Fungal
  • Antibodies, Monoclonal
  • Antigens, Fungal
  • Glucuronates
  • Mannans
  • Polysaccharides