Sensitivity of HIV-1 to neutralization by antibodies against O-linked carbohydrate epitopes despite deletion of O-glycosylation signals in the V3 loop.

Important note: Information in this article was accurate in 1996. The state of the art may have changed since the publication date.

Sensitivity of HIV-1 to neutralization by antibodies against O-linked carbohydrate epitopes despite deletion of O-glycosylation signals in the V3 loop.

Arch Virol. 1996;141(2):291-300. Unique Identifier : AIDSLINE MED/96195257
Hansen JE; Jansson B; Gram GJ; Clausen H; Nielsen JO; Olofsson S; Laboratory for Infectious Diseases, Hvidovre Hospital, Hvidovre,; Denmark.

Abstract: It has been suggested that threonine or serine residues in the V3 loop of HIV-1 gp120 are glycosylated with the short-chain O-linked oligosaccharides Tn or sialosyl-Tn that function as epitopes for broadly neutralizing carbohydrate specific antibodies. In this study we examined whether mutation of such threonine or serine residues could decrease the sensitivity to infectivity inhibition by Tn or sialosyl-Tn specific antibodies. All potentially O-glycosylated threonine and serine residues in the V3 loop of cloned HIV-1 BRU were mutagenized to alanine thus abrogating any O-glycosylation at these sites. Additionally, one of these T-A mutants (T308A) also abrogated the signal for N-glycosylation at N306 inside the V3-loop. The mutant clones were compared with the wild type virus as to sensitivity to neutralization with monoclonal and polyclonal antibodies specific for the tip of the V3 loop of BRU or for the O-linked oligosaccharides Tn or sialosyl-Tn. Deletion of the N-linked oligosaccharide at N306 increased the neutralization sensitivity to antibodies specific for the tip of the loop, which indicates that N-linked glycosylation modulates the accessibility to this immunodominant epitope. However, none of the mutants with deletions of O-glycosylation signals in the V3 loop displayed any decrease in sensitivity to anti-Tn or anti-sialosyl-Tn antibody. This indicates that these broadly specific neutralization epitopes are located outside the V3 loop of gp 120.

Keywords: Amino Acid Sequence Cloning, Molecular Enzyme-Linked Immunosorbent Assay Epitopes/ANALYSIS/IMMUNOLOGY Glycosylation Human *HIV Antibodies HIV Envelope Protein gp120/BIOSYNTHESIS/CHEMISTRY/*IMMUNOLOGY HIV-1/*IMMUNOLOGY Molecular Sequence Data Mutagenesis, Site-Directed Neutralization Tests Point Mutation Protein Structure, Secondary Recombinant Proteins/BIOSYNTHESIS/CHEMISTRY/IMMUNOLOGY Sensitivity and Specificity Sequence Deletion Serine Support, Non-U.S. Gov't Threonine JOURNAL ARTICLE
960930
M9690849

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