Evidence against extracellular exposure of a highly immunogenic region in the C-terminal domain of the simian immunodeficiency virus gp41 transmembrane protein

Thomas S. Postler, José M. Martinez-Navio, Eloísa Yuste, Ronald Charles Desrosiers

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The generally accepted model for human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein topology includes a single membrane-spanning domain. An alternate model has been proposed which features multiple membrane-spanning domains. Consistent with the alternate model, a high percentage of HIV-1-infected individuals produce unusually robust antibody responses to a region of envelope, the so-called "Kennedy epitope," that in the conventional model should be in the cytoplasm. Here we show analogous, robust antibody responses in simian immunodeficiency virus SIVmac239-infected rhesus macaques to a region of SIVmac239 envelope located in the C-terminal domain, which in the conventional model should be inside the cell. Sera from SIV-infected rhesus macaques consistently reacted with overlapping oligopeptides corresponding to a region located within the cytoplasmic domain of gp41 by the generally accepted model, at intensities comparable to those observed for immunodominant areas of the surface component gp120. Rabbit serum raised against this highly immunogenic region (HIR) reacted with SIV envelope in cell surface-staining experiments, as did monoclonal anti-HIR antibodies isolated from an SIVmac239-infected rhesus macaque. However, control experiments demonstrated that this surface staining could be explained in whole or in part by the release of envelope protein from expressing cells into the supernatant and the subsequent attachment to the surfaces of cells in the culture. Serum and monoclonal antibodies directed against the HIR failed to neutralize even the highly neutralization-sensitive strain SIVmac316. Furthermore, a potential N-linked glycosylation site located close to the HIR and postulated to be outside the cell in the alternate model was not glycosylated. An artificially introduced glycosylation site within the HIR was also not utilized for glycosylation. Together, these data support the conventional model of SIV envelope as a type Ia transmembrane protein with a single membrane-spanning domain and without any extracellular loops.

Original languageEnglish (US)
Pages (from-to)1145-1157
Number of pages13
JournalJournal of Virology
Volume86
Issue number2
DOIs
StatePublished - Jan 2012
Externally publishedYes

Fingerprint

Simian immunodeficiency virus
transmembrane proteins
Macaca mulatta
Glycosylation
Antibody Formation
Membranes
HIV-1
glycosylation
Serum
Staining and Labeling
Simian Immunodeficiency Virus
Oligopeptides
Human immunodeficiency virus 1
antibodies
Epitopes
Glycoproteins
Cytoplasm
Proteins
Cell Culture Techniques
Monoclonal Antibodies

ASJC Scopus subject areas

  • Immunology
  • Virology

Cite this

Evidence against extracellular exposure of a highly immunogenic region in the C-terminal domain of the simian immunodeficiency virus gp41 transmembrane protein. / Postler, Thomas S.; Martinez-Navio, José M.; Yuste, Eloísa; Desrosiers, Ronald Charles.

In: Journal of Virology, Vol. 86, No. 2, 01.2012, p. 1145-1157.

Research output: Contribution to journalArticle

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