Probing the structure of the V2 domain of human immunodeficiency virus type 1 surface glycoprotein gp120 with a panel of eight monoclonal antibodies: human immune response to the V1 and V2 domains

Moore, John P.; Sattentau, Quentin J.; Yoshiyama, Hironori; Thali, Markus; Charles, Marie‐Hélène; Sullivan, Nancy; Poon, Shu-Wing; Fung, Michael; Traincard, François; Pinkus, Mary S.

doi:10.1128/jvi.67.10.6136-6151.1993

Cited by 121 publications

(137 citation statements)

References 55 publications

(81 reference statements)

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“…An involvement of the V2 loop in the gp120 intersubunit contact site is also consistent with a number of reports suggesting that epitopes within this domain are less accessible to MAb binding to cell surface-expressed versus soluble purified gp120 (34,37,39). Moreover, it has also been shown that sera from infected individuals have few antibodies against V1/V2 epitopes (25). Within the V2 domain, it appears that epitopes located at the tip of the loop are relatively more occluded in cell surface-expressed gp120 than those in the N-terminal flank (37), supporting the role of the tip segment in association.…”

Section: Discussionsupporting

confidence: 90%

The Human Immunodeficiency Virus Type 1 gp120 V2 Domain Mediates gp41-Independent Intersubunit Contacts

et al. 2000

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The envelope protein of human immunodeficiency virus type 1 HIV-1 undergoes proteolytic cleavage in the Golgi complex to produce subunits designated gp120 and gp41, which remain noncovalently associated. While gp41 has a well-characterized oligomeric structure, the maintenance of gp41-independent gp120 intersubunit contacts remains a contentious issue. Using recombinant vaccinia virus to achieve high-level expression of gp120 in mammalian cells combined with gel filtration analysis, we were able to isolate a discrete oligomeric form of gp120. Oligomerization of gp120 occurred intracellularly between 30 and 120 min after synthesis. Analysis by sedimentation equilibrium unequivocally identified the oligomeric species as a dimer. In order to identify the domains involved in the intersubunit contact, we expressed a series of gp120 proteins lacking various domains and assessed the effects of mutation on oligomeric structure. Deletion of the V1 or V3 loops had little effect on the relative amounts of monomer and dimer in comparison to wild-type gp120. In contrast, deletion of either all or part of the V2 loop drastically reduced dimer formation, indicating that this domain is required for intersubunit contact formation. Consistent with this, the V2 loop of the dimer was less accessible than that of the monomer to a specific monoclonal antibody. Previous studies have shown that while the V2 loop is not an absolute requirement for viral entry, the absence of this domain reduces viral resistance to neutralization by monoclonal antibodies or sera. We propose that the quaternary structure of gp120 may contribute to resistance to neutralization by limiting the exposure of conserved epitopes.The envelope (env) proteins of human immunodeficiency virus type 1 (HIV-1) mediate viral entry and are the primary targets of neutralizing antibodies. Following synthesis and posttranslational modifications in the endoplasmic reticulum, including N-linked glycosylation, disulfide bond formation, and oligomerization, the env protein precursor gp160 passes through the Golgi complex where it is cleaved to form subunits designated gp120 and gp41 (11,41). A noncovalently associated oligomeric gp120-gp41 complex is transported to the surface of infected cells, where incorporation into budding virions occurs. The binding of virion-associated or infected-cell-associated gp120 to the CD4 receptor induces conformational changes that promote subsequent interaction with one of a number of chemokine receptors (19,46,49). Movement of the variable (V) loop structure V1/V2 following CD4 binding has been shown to result in increased exposure of an antibody epitope which overlaps with the chemokine receptor binding site (44,52). Receptor binding-induced env conformational changes are believed to culminate in the exposure of the gp41 fusion peptide and its repositioning toward the target cell prior to fusion of the membranes of the infected cell or virion and the target cell (5,14,26,48).Despite numerous investigations, the oligomeric structure of the nativ...

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Section: Discussionsupporting

confidence: 90%

The Human Immunodeficiency Virus Type 1 gp120 V2 Domain Mediates gp41-Independent Intersubunit Contacts

et al. 2000

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“…Neutralizing antisera and mAbs have been raised against gp120 in the form of recombinant or purified glycoprotein or synthetic peptides, or during natural infection with the virus . For many mAbs, their epitopes have been mapped by analysis of their binding to synthetic peptides (5-16, 18, 21, 22, 24), recombinant glycoproteins containing site-directed mutations (25)(26)(27), or a combination of both strategies (19,20,23). Such analyses have allowed a partial understanding of the exposure and spatial relationship of these mAb epitopes on gp120 (19,20,(22)(23)(24)(25)(26)(27)(28).…”

Section: Sllmmarymentioning

confidence: 99%

Human immunodeficiency virus type 1 neutralization is determined by epitope exposure on the gp120 oligomer.

Sattentau

Moore

1995

The Journal of Experimental Medicine

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322

249

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SllmmaryThe major target of the neutralizing antibody response to infection by the human immunodeficiency virus type 1 (HIV-1) is the outer envelope glycoprotein, gp120. The spectrum of HIV-1 neutralization specificity is currently represented by monoclonal antibodies (mAbs) that can be divided broadly into five groups. We have studied the binding of these mAbs to functional oligomeric and soluble monomeric gp120 derived from the molecular clone of a cell line-adapted isolate of HIV-1, and compared these binding properties with virus neutralization. Binding of all mAbs except those reactive with the V3 loop was much weaker to oligomeric than to monomeric gp120. This reduction in binding to oligomeric gp120 was determined mostly by a slower relative rate of association, although the dissociation rate also had some influence on relative variation in mAb affinity. Virus neutralization correlated broadly with mAb binding to the oligomeric rather than to the monomeric form of gp120, and neutralization potency was related to the estimated association rate. Thus, with the exception of the hypervariable V3 loop, regions of HIV-1 gp120 with the potential to induce a neutralization response are likely to be poorly presented for antibody recognition on the surface of cell line-adapted virions.

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“…This is important not only when comparing experimental results within the laboratory, but also when comparing results with those of other laboratories. In addition to the V3 loop, other neutralizing sites include epitopes in the C2 [Ho et al, 1988] and V2 [Moore et al, 1993] regions of gp120, as well as in gp41 [Dalgleish et al, 1988], and a conformational epitope that overlaps the CD4 binding region of the envelope glycoprotein. Escape from neutralizing antisera may also occur through mutations in one of these epitopes and influence the binding of different antibodies to numerous sites on the protein.…”

Section: Discussionmentioning

confidence: 99%

Neutralization of HIV‐1 subtypes: Implications for vaccine formulations

1998

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More than 20.8 million people are infected with HIV in sub-Saharan Africa, with South Africa having one of the fastest growing HIV-1 epidemics, where an estimated 2.4 million people were infected. Thirty-two sera from 25 patients were tested for their ability to neutralize HTLV-IIIB (IIIB) and four primary isolates representing subtypes B, C, D, and a recombinant gag C/env B type. A CEM-SS cell line-based assay was used and the neutralizing titer was defined as the reciprocal of the highest dilution giving a 50% reduction in p24 antigen production. All isolates were neutralized better by subtype-specific sera, except for the C4714 strain, which was neutralized by both subtype B and C sera. C4714 was neutralized by 18/25 (72%) sera, IIIB by 19/32 (59%) sera, D482 by 7/31(23%) sera, B3245 by 6/29 (21%) sera, and the recombinant B/C1491 isolate by 4/25 (16%) sera. Five sera were unable to neutralize any of the isolates. The V3 region of the isolates used in the neutralization assay was amplified by PCR, directly sequenced, and analyzed to reveal variability between the consensus HIV-1 sequences and the isolates. HIV-1 strain C4714 was neutralized more effectively with the sera tested than the IIIIB laboratory strain. Variability in the amino acid sequence of the V3 region, which can alter the conformation of the V3 loop secondary structure, can influence the neutralization of a particular viral isolate. Vaccine formulations should be broadened to include multiple subtypes, especially C subtypes, which is rapidly spreading worldwide.

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Probing the structure of the V2 domain of human immunodeficiency virus type 1 surface glycoprotein gp120 with a panel of eight monoclonal antibodies: human immune response to the V1 and V2 domains

Cited by 121 publications

References 55 publications

The Human Immunodeficiency Virus Type 1 gp120 V2 Domain Mediates gp41-Independent Intersubunit Contacts

The Human Immunodeficiency Virus Type 1 gp120 V2 Domain Mediates gp41-Independent Intersubunit Contacts

Human immunodeficiency virus type 1 neutralization is determined by epitope exposure on the gp120 oligomer.

Neutralization of HIV‐1 subtypes: Implications for vaccine formulations

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