Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2008 Jul;82(13):6359-68.
doi: 10.1128/JVI.00293-08. Epub 2008 Apr 23.

A glycoconjugate antigen based on the recognition motif of a broadly neutralizing human immunodeficiency virus antibody, 2G12, is immunogenic but elicits antibodies unable to bind to the self glycans of gp120

Rena D Astronomo  1 , Hing-Ken Lee, Christopher N Scanlan, Ralph Pantophlet, Cheng-Yuan Huang, Ian A Wilson, Ola Blixt, Raymond A Dwek, Chi-Huey Wong, Dennis R Burton
Affiliations
Comparative Study

A glycoconjugate antigen based on the recognition motif of a broadly neutralizing human immunodeficiency virus antibody, 2G12, is immunogenic but elicits antibodies unable to bind to the self glycans of gp120

Rena D Astronomo et al. J Virol. 2008 Jul.

Abstract

The glycan shield of human immunodeficiency virus type 1 (HIV-1) gp120 contributes to viral evasion from humoral immune responses. However, the shield is recognized by the HIV-1 broadly neutralizing antibody (Ab), 2G12, at a relatively conserved cluster of oligomannose glycans. The discovery of 2G12 raises the possibility that a carbohydrate immunogen may be developed that could elicit 2G12-like neutralizing Abs and contribute to an AIDS vaccine. We have previously dissected the fine specificity of 2G12 and reported that the synthetic tetramannoside (Man(4)) that corresponds to the D1 arm of Man(9)GlcNAc(2) inhibits 2G12 binding to gp120 as efficiently as Man(9)GlcNAc(2) itself, indicating the potential use of Man(4) as a building block for creating immunogens. Here, we describe the development of neoglycoconjugates displaying variable copy numbers of Man(4) on bovine serum albumin (BSA) molecules by conjugation to Lys residues. The increased valency enhances the apparent affinity of 2G12 for Man(4) up to a limit which is achieved at approximately 10 copies per BSA molecule, beyond which no further enhancement is observed. Immunization of rabbits with BSA-(Man(4))(14) elicits significant serum Ab titers to Man(4). However, these Abs are unable to bind gp120. Further analysis reveals that the elicited Abs bind a variety of unbranched and, to a lesser extent, branched Man(9) derivatives but not natural N-linked oligomannose containing the chitobiose core. These results suggest that Abs can be readily elicited against the D1 arm; however, potential differences in the presentation of Man(4) on neoglycoconjugates, compared to glycoproteins, poses challenges for eliciting anti-mannose Abs capable of cross-reacting with gp120 and HIV-1.

PubMed Disclaimer

Figures

FIG. 1.
FIG. 1.
Synthetic scheme for the conjugation of Man4 to BSA. n, number of Man4 moieties conjugated to different Lys residues on BSA.
FIG. 2.
FIG. 2.
Binding of serum IgG from BSA-(Man4)14--immunized (top panel) and control (BSA)-immunized animals (bottom panel) to gp120 and Man4 glycoconjugates. (A) Binding of serially diluted sera from BSA-(Man4)14- and BSA-immunized rabbits to immobilized gp120, BSA-(Man4)14, and Ova in the presence of 1% BSA as measured by ELISA. (B) Comparison of BSA-(Man4)14 serum and BSA serum IgG binding to Man4 presented on BSA [BSA-(Man4)14] and Ova [Ova-(Man4)10]. Open symbols denote preimmune serum samples, and filled symbols denote serum samples taken after the last booster injection [bleeds 4 and 5 for BSA and BSA-(Man4)14, respectively]. OD, optical density.
FIG. 3.
FIG. 3.
Comparison of the abilities of different mannose ligands to compete with BSA-(Man4)14 immune serum IgG for binding to BSA-(Man4)14. The percent inhibition of serum IgG binding, as measured by ELISA, to BSA-(Man4)14 for d-mannose, Man3, Man4, and Man7. Serum from the fifth bleed was assayed at a 1:400 dilution. x axis, serum sample (rabbit identifier); y axis, percent inhibition of glycoconjugate binding; z axis, soluble mannoside competitor at 2 mM (or 200 mM for d-mannose, indicated by the asterisk). Symbolic representations of the ligands are included for reference.
FIG. 4.
FIG. 4.
Immunogenicity of Man4 as presented on BSA-(Man4)14 in rabbits: serum IgG recognition of α-d-mannose and various synthetic and naturally derived oligomannosides present on the printed glycan array, version 3.0. (A) Binding of prebleed and final bleed sera, diluted 1:200, to oligomannose glycans as measured by fluorescence (y axis). Individual glycans assayed are referenced by the glycan identification numbers on the printed array (x axis). Immune serum data are plotted directly above each glycan identification number, while preimmune serum data for the corresponding sugar are plotted above the preceding asterisk. Each symbol corresponds to a single rabbit in either the BSA group or the BSA-(Man4)14 group. For the BSA group, the symbols are as follows: green square, rabbit 18671; red triangle, 18672; open circle, 18673; and blue diamond, 18674. For the BSA-(Man4)14 group, the symbols are as follows: green square, rabbit 18667; red triangle, 18668; open circle, 18669; and blue diamond, 18670. (B) Symbolic representations of the oligosaccharide structures corresponding to the glycan identification numbers in panel A shown in the context of the larger Man9GlcNAc2 parent structure. Note that glycan 9 is not depicted as it represents the monosaccharide α-d-mannose.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Baba, T. W., V. Liska, R. Hofmann-Lehmann, J. Vlasak, W. Xu, S. Ayehunie, L. A. Cavacini, M. R. Posner, H. Katinger, G. Stiegler, B. J. Bernacky, T. A. Rizvi, R. Schmidt, L. R. Hill, M. E. Keeling, Y. Lu, J. E. Wright, T. C. Chou, and R. M. Ruprecht. 2000. Human neutralizing monoclonal antibodies of the IgG1 subtype protect against mucosal simian-human immunodeficiency virus infection. Nat. Med. 6200-206. - PubMed
    1. Barbas, C. F., III, T. A. Collet, W. Amberg, P. Roben, J. M. Binley, D. Hoekstra, D. Cababa, T. M. Jones, R. A. Williamson, G. R. Pilkington, et al. 1993. Molecular profile of an antibody response to HIV-1 as probed by combinatorial libraries. J. Mol. Biol. 230812-823. - PubMed
    1. Beirnaert, E., S. De Zutter, W. Janssens, and G. van der Groen. 2001. Potent broad cross-neutralizing sera inhibit attachment of primary HIV-1 isolates (groups M and O) to peripheral blood mononuclear cells. Virology 281305-314. - PubMed
    1. Binley, J. M., T. Wrin, B. Korber, M. B. Zwick, M. Wang, C. Chappey, G. Stiegler, R. Kunert, S. Zolla-Pazner, H. Katinger, C. J. Petropoulos, and D. R. Burton. 2004. Comprehensive cross-clade neutralization analysis of a panel of anti-human immunodeficiency virus type 1 monoclonal antibodies. J. Virol. 7813232-13252. - PMC - PubMed
    1. Blixt, O., S. Head, T. Mondala, C. Scanlan, M. E. Huflejt, R. Alvarez, M. C. Bryan, F. Fazio, D. Calarese, J. Stevens, N. Razi, D. J. Stevens, J. J. Skehel, I. van Die, D. R. Burton, I. A. Wilson, R. Cummings, N. Bovin, C. H. Wong, and J. C. Paulson. 2004. Printed covalent glycan array for ligand profiling of diverse glycan binding proteins. Proc. Natl. Acad. Sci. USA 10117033-17038. - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources