A Short Segment of the HIV-1 gp120 V1/V2 Region Is a Major Determinant of Resistance to V1/V2 Neutralizing Antibodies

Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.
Journal of Virology (Impact Factor: 4.44). 05/2012; 86(15):8319-23. DOI: 10.1128/JVI.00696-12
Source: PubMed


Antibody PG9 is a prototypical member of a class of V1/V2-directed antibodies that effectively neutralizes diverse strains of HIV-1. We analyzed strain-specific resistance to PG9 using sequence and structural information. For multiply resistant strains, mutations in a short segment of V1/V2 resulted in gain of sensitivity to PG9 and related V1/V2 neutralizing antibodies, suggesting both a common mechanism of HIV-1 resistance to and a common mode of recognition by this class of antibodies.

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Available from: Dennis R Burton, Oct 03, 2015
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    • "Our approach could not distinguish between the glycan- vs. protein-associated epitopes, as evidenced by the partially retained reactivities of antibodies recognizing glycans on the partially deglycosylated gp120 (PGT121, 2G12, PG16, PG9) [40,47,48,83,91]. However, our tests characterized overall interactions of antibodies with differentially glycosylated gp120 oligomers and discriminated between various glycoforms of gp120 as targets for a panel of well characterized broadly neutralizing monoclonal antibodies. "
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    ABSTRACT: Background HIV-1 entry into host cells is mediated by interactions between the virus envelope glycoprotein (gp120/gp41) and host-cell receptors. N-glycans represent approximately 50% of the molecular mass of gp120 and serve as potential antigenic determinants and/or as a shield against immune recognition. We previously reported that N-glycosylation of recombinant gp120 varied, depending on the producer cells, and the glycosylation variability affected gp120 recognition by serum antibodies from persons infected with HIV-1 subtype B. However, the impact of gp120 differential glycosylation on recognition by broadly neutralizing monoclonal antibodies or by polyclonal antibodies of individuals infected with other HIV-1 subtypes is unknown. Methods Recombinant multimerizing gp120 antigens were expressed in different cells, HEK 293T, T-cell, rhabdomyosarcoma, hepatocellular carcinoma, and Chinese hamster ovary cell lines. Binding of broadly neutralizing monoclonal antibodies and polyclonal antibodies from sera of subtype A/C HIV-1-infected subjects with individual gp120 glycoforms was assessed by ELISA. In addition, immunodetection was performed using Western and dot blot assays. Recombinant gp120 glycoforms were tested for inhibition of infection of reporter cells by SF162 and YU.2 Env-pseudotyped R5 viruses. Results We demonstrated, using ELISA, that gp120 glycans sterically adjacent to the V3 loop only moderately contribute to differential recognition of a short apex motif GPGRA and GPGR by monoclonal antibodies F425 B4e8 and 447-52D, respectively. The binding of antibodies recognizing longer peptide motifs overlapping with GPGR epitope (268 D4, 257 D4, 19b) was significantly altered. Recognition of gp120 glycoforms by monoclonal antibodies specific for other than V3-loop epitopes was significantly affected by cell types used for gp120 expression. These epitopes included CD4-binding site (VRC03, VRC01, b12), discontinuous epitope involving V1/V2 loop with the associated glycans (PG9, PG16), and an epitope including V3-base-, N332 oligomannose-, and surrounding glycans-containing epitope (PGT 121). Moreover, the different gp120 glycoforms variably inhibited HIV-1 infection of reporter cells. Conclusion Our data support the hypothesis that the glycosylation machinery of different cells shapes gp120 glycosylation and, consequently, impacts envelope recognition by specific antibodies as well as the interaction of HIV-1 gp120 with cellular receptors. These findings underscore the importance of selection of appropriately glycosylated HIV-1 envelope as a vaccine antigen.
    AIDS Research and Therapy 08/2014; 11(1):23. DOI:10.1186/1742-6405-11-23 · 1.46 Impact Factor
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    • "We are particularly interested in the participation of the V2 region in the trimer association domain (TAD) because so little is known about its structure and function. However, the V2 region is immunogenic, and in some cases serves as a target for broadly cross-reactive neutralizing antibodies [11], [30]–[34]. Recent data from antibody complexes with V2 peptides indicate that the V2 region of HIV-1 can potentially assume multiple conformations, depending on context [35], [36]. "
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    ABSTRACT: The V1 and V2 variable regions of the primate immunodeficiency viruses contribute to the trimer association domain of the gp120 exterior envelope glycoprotein. A pair of V2 cysteine residues at 183 and 191 ("twin cysteines") is present in several simian immunodeficiency viruses, human immunodeficiency virus type 2 (HIV-2) and some SIVcpz lineages, but not in HIV-1. To examine the role of this potentially disulfide-bonded twin-cysteine motif, the cysteine residues in the SIVmac239 envelope glycoproteins were individually and pairwise substituted by alanine residues. All of the twin-cysteine mutants exhibited decreases in gp120 association with the Env trimer, membrane-fusing activity, and ability to support virus entry. Thus, the twin-cysteine motif plays a role in Env trimer stabilization in SIV and may do so in HIV-2 and some SIVcpz as well. This implies that HIV-1 lost the twin-cysteines, and may have relatively unstable Env trimers compared to SIV and HIV-2.
    PLoS ONE 07/2013; 8(7):e69406. DOI:10.1371/journal.pone.0069406 · 3.23 Impact Factor
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    ABSTRACT: Neutralizing antibody protection against HIV-1 may require broad and potent antibodies targeting multiple epitopes. We tested 7 monoclonal antibodies (MAbs) against 45 viruses of diverse subtypes from early infection. The CD4 binding site MAb NIH45-46W was most broad and potent (91% coverage; geometric mean 50% inhibitory concentration [IC(50)], 0.09 μg/ml). Combining NIH45-46W and a V3-specific MAb, PGT128, neutralized 96% of viruses, while PGT121, another V3-specific MAb, neutralized the remainder. Thus, 2 or 3 antibody specificities may prevent infection by most HIV-1 variants.
    Journal of Virology 07/2012; 86(19):10857-61. DOI:10.1128/JVI.01414-12 · 4.44 Impact Factor
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