scholarly journals Monoclonal Antibodies to Phosphatidylinositol Phosphate Neutralize Human Immunodeficiency Virus Type 1: Role of Phosphate-Binding Subsites

2006 ◽  
Vol 81 (4) ◽  
pp. 2087-2091 ◽  
Author(s):  
Bruce K. Brown ◽  
Nicos Karasavvas ◽  
Zoltan Beck ◽  
Gary R. Matyas ◽  
Deborah L. Birx ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Enzyme Linked Immunosorbent Assay ◽  
Phosphate Binding ◽  
Phosphatidylinositol Phosphate ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Both a murine monoclonal antibody to phosphatidylinositol phosphate (PIP) and a human monoclonal antibody (4E10) that is known to have broadly neutralizing capabilities against primary isolates of human immunodeficiency virus type 1 (HIV-1) bound to PIP, as determined by enzyme-linked immunosorbent assay. Each of the antibodies had antigen subsite binding specificities in aqueous medium for small phosphate-containing molecules and for inositol. The anti-PIP monoclonal antibody inhibited infection by two HIV-1 primary isolates in neutralization assays employing primary human peripheral blood mononuclear cells. The data suggest that PIP or related lipids having free phosphates could serve as targets for the neutralization of HIV-1.

scholarly journals Structure-Function Analysis of the Epitope for 4E10, a Broadly Neutralizing Human Immunodeficiency Virus Type 1 Antibody

2006 ◽  
Vol 80 (4) ◽  
pp. 1680-1687 ◽  
Author(s):  
Florence M. Brunel ◽  
Michael B. Zwick ◽  
Rosa M. F. Cardoso ◽  
Josh D. Nelson ◽  
Ian A. Wilson ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Function Analysis ◽  
Enzyme Linked Immunosorbent Assay ◽  
Peptide Epitope ◽  
Immunodeficiency Virus ◽  
Hiv 1 ◽  
4E10 Antibody

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) neutralizing antibody 4E10 binds to a linear, highly conserved epitope within the membrane-proximal external region of the HIV-1 envelope glycoprotein gp41. We have delineated the peptide epitope of the broadly neutralizing 4E10 antibody to gp41 residues 671 to 683, using peptides with different lengths encompassing the previously suggested core epitope (NWFDIT). Peptide binding to the 4E10 antibody was assessed by competition enzyme-linked immunosorbent assay, and the Kd values of selected peptides were determined using surface plasmon resonance. An Ala scan of the epitope indicated that several residues, W672, F673, and T676, are essential (>1,000-fold decrease in binding upon replacement with alanine) for 4E10 recognition. In addition, five other residues, N671, D674, I675, W680, and L679, make significant contributions to 4E10 binding. In general, the Ala scan results agree well with the recently reported crystal structure of 4E10 in complex with a 13-mer peptide and with our circular dichroism analyses. Neutralization competition assays confirmed that the peptide NWFDITNWLWYIKKKK-NH2 could effectively inhibit 4E10 neutralization. Finally, to limit the conformational flexibility of the peptides, helix-promoting 2-aminoisobutyric acid residues and helix-inducing tethers were incorporated. Several peptides have significantly improved affinity (>1,000-fold) over the starting peptide and, when used as immunogens, may be more likely to elicit 4E10-like neutralizing antibodies. Hence, this study represents the first stage toward iterative development of a vaccine based on the 4E10 epitope.

scholarly journals Potent, Broad-Spectrum Inhibition of Human Immunodeficiency Virus Type 1 by the CCR5 Monoclonal Antibody PRO 140

2001 ◽  
Vol 75 (2) ◽  
pp. 579-588 ◽  
Author(s):  
Alexandra Trkola ◽  
Thomas J. Ketas ◽  
Kirsten A. Nagashima ◽  
Lu Zhao ◽  
Tonie Cilliers ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Broad Spectrum ◽  
Mononuclear Cells ◽  
Subtype C ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT CCR5 serves as a requisite fusion coreceptor for clinically relevant strains of human immunodeficiency virus type 1 (HIV-1) and provides a promising target for antiviral therapy. However, no study to date has examined whether monoclonal antibodies, small molecules, or other nonchemokine agents possess broad-spectrum activity against the major genetic subtypes of HIV-1. PRO 140 (PA14) is an anti-CCR5 monoclonal antibody that potently inhibits HIV-1 entry at concentrations that do not affect CCR5's chemokine receptor activity. In this study, PRO 140 was tested against a panel of primary HIV-1 isolates selected for their genotypic and geographic diversity. In quantitative assays of viral infectivity, PRO 140 was compared with RANTES, a natural CCR5 ligand that can inhibit HIV-1 entry by receptor downregulation as well as receptor blockade. Despite their divergent mechanisms of action and binding epitopes on CCR5, low nanomolar concentrations of both PRO 140 and RANTES inhibited infection of primary peripheral blood mononuclear cells (PBMC) by all CCR5-using (R5) viruses tested. This is consistent with there being a highly restricted pattern of CCR5 usage by R5 viruses. In addition, a panel of 25 subtype C South African R5 viruses were broadly inhibited by PRO 140, RANTES, and TAK-779, although ∼30-fold-higher concentrations of the last compound were required. Interestingly, significant inhibition of a dualtropic subtype C virus was also observed. Whereas PRO 140 potently inhibited HIV-1 replication in both PBMC and primary macrophages, RANTES exhibited limited antiviral activity in macrophage cultures. Thus CCR5-targeting agents such as PRO 140 can demonstrate potent and genetic-subtype-independent anti-HIV-1 activity.

scholarly journals Two N-Linked Glycosylation Sites in the V2 and C2 Regions of Human Immunodeficiency Virus Type 1 CRF01_AE Envelope Glycoprotein gp120 Regulate Viral Neutralization Susceptibility to the Human Monoclonal Antibody Specific for the CD4 Binding Domain

2010 ◽  
Vol 84 (9) ◽  
pp. 4311-4320 ◽  
Author(s):  
Piraporn Utachee ◽  
Shota Nakamura ◽  
Panasda Isarangkura-na-ayuthaya ◽  
Kenzo Tokunaga ◽  
Pathom Sawanpanyalert ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Human Monoclonal Antibody ◽  
Binding Domain ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT A recombinant human monoclonal antibody, IgG1 b12 (b12), recognizes a conformational epitope on human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) gp120 that overlaps the CD4 binding domain. Although b12 is able to broadly neutralize HIV-1 subtype B, C, and D viruses, many HIV-1 CRF01_AE viruses are resistant to b12-mediated neutralization. In this report, we examined the molecular mechanisms underlying the low neutralization susceptibility of CRF01_AE viruses to b12, using recently established CRF01_AE Env recombinant viruses. Our results showed that two potential N-linked glycosylation (PNLG) sites in the V2 and C2 regions of Env gp120 played an important role in regulating the susceptibility of CRF01_AE Env to b12. The locations of these PNLG sites correspond to amino acid positions 186 and 197 in HXB2 Env gp120; thus, they are designated N186 and N197 in this study. Removal of N186 significantly conferred the b12 susceptibility of 2 resistant CRF01_AE Env clones, 65CC4 and 107CC2, while the introduction of N186 reduced the b12 susceptibility of a susceptible CRF01_AE Env clone, 65CC1. In addition, removal of both N186 and N197 conferred the b12 susceptibility of 3 resistant CRF01_AE Env clones, 45PB1, 62PL1, and 101PL1, whereas the removal of either N186 or N197 was not sufficient to confer the b12 susceptibility of these CRF01_AE Env clones. Finally, removal of N197 conferred the b12 susceptibility of 2 resistant CRF01_AE Env clones lacking N186, 55PL1 and 102CC2. Taken together, we propose that two PNLG sites, N186 and N197, in Env gp120 are important determinants of the b12 resistance of CRF01_AE viruses.

scholarly journals Impact of V2 Mutations on Escape from a Potent Neutralizing Anti-V3 Monoclonal Antibody during In Vitro Selection of a Primary Human Immunodeficiency Virus Type 1 Isolate

2007 ◽  
Vol 81 (8) ◽  
pp. 3757-3768 ◽  
Author(s):  
Junji Shibata ◽  
Kazuhisa Yoshimura ◽  
Akiko Honda ◽  
Atsushi Koito ◽  
Toshio Murakami ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
Amino Acid ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Immunodeficiency Virus ◽  
Amino Acid Mutations ◽  
Hiv 1

ABSTRACT KD-247, a humanized monoclonal antibody to an epitope of gp120-V3 tip, has potent cross-neutralizing activity against subtype B primary human immunodeficiency virus type 1 (HIV-1) isolates. To assess how KD-247 escape mutants can be generated, we induced escape variants by exposing bulked primary R5 virus, MOKW, to increasing concentrations of KD-247 in vitro. In the presence of relatively low concentrations of KD-247, viruses with two amino acid mutations (R166K/D167N) in V2 expanded, and under high KD-247 pressure, a V3 tip substitution (P313L) emerged in addition to the V2 mutations. However, a virus with a V2 175P mutation dominated during passaging in the absence of KD-247. Using domain swapping analysis, we demonstrated that the V2 mutations and the P313L mutation in V3 contribute to partial and complete resistance phenotypes against KD-247, respectively. To identify the V2 mutation responsible for the resistance to KD-247, we constructed pseudoviruses with single or double amino acid mutations in V2 and measured their sensitivity to neutralization. Interestingly, the neutralization phenotypes were switched, so that amino acid residue 175 (Pro or Leu) located in the center of V2 was exchanged, indicating that the amino acid at position 175 has a crucial role, dramatically changing the Env oligomeric state on the membrane surface and affecting the neutralization phenotype against not only anti-V3 antibody but also recombinant soluble CD4. These data suggested that HIV-1 can escape from anti-V3 antibody attack by changing the conformation of the functional envelope oligomer by acquiring mutations in the V2 region in environments with relatively low antibody concentrations.

scholarly journals Fruit-Specific Expression of the Human Immunodeficiency Virus Type 1 Tat Gene in Tomato Plants and Its Immunogenic Potential in Mice

2007 ◽  
Vol 14 (6) ◽  
pp. 685-692 ◽  
Author(s):  
Yuri Jorge Peña Ramírez ◽  
Ennio Tasciotti ◽  
Abel Gutierrez-Ortega ◽  
Alberto J. Donayre Torres ◽  
María Teresa Olivera Flores ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Tomato Fruit ◽  
Enzyme Linked Immunosorbent Assay ◽  
Potential Candidate ◽  
Tat Protein ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Tat protein is considered a potential candidate vaccine antigen. In an effort to design a strategy for noninvasive vaccination against HIV-1, we developed transgenic tomatoes expressing the Tat protein. Two independent plants testing positive in transgene detection analysis were selected and grown to maturity. Monoclonal antibodies against Tat recognized a protein of the expected size. Interestingly, expression of Tat seemed to be toxic to the plant, as in all cases the fruit exhibited underdeveloped reproductive structures and no seeds. Nine groups of 10 pathogen-free BALB/c male mice were primed either orally, intraperitoneally, or intramuscularly with 10 mg of tomato fruit extract derived from transgenic or wild-type plants and with 10 μg of Tat86 recombinant protein. Mice were immunized at days 0, 14, and 28, and given boosters after 15 weeks; sera were drawn 7 days after each booster, and the antibody titer was determined by enzyme-linked immunosorbent assay. All three immunization approaches induced the development of a strong anti-Tat immunological response, which increased over time. Isotype subclass determination showed the presence of mucosal (immunoglobulin A) immunity soon after the beginning of the oral immunization protocol, and the data were confirmed by the presence of anti-Tat antibodies in fecal pellets and in vaginal washes. We also demonstrated that sera from immunized mice inhibited with high efficiency recombinant Tat-dependent transactivation of the HIV-1 long terminal repeat promoter. This neutralization activity might be relevant for the suppression of extracellular Tat activities, which play an important role in HIV disease development.

scholarly journals Sequential Immunization with V3 Peptides from Primary Human Immunodeficiency Virus Type 1 Produces Cross-Neutralizing Antibodies against Primary Isolates with a Matching Narrow-Neutralization Sequence Motif

2006 ◽  
Vol 80 (11) ◽  
pp. 5552-5562 ◽  
Author(s):  
Yasuyuki Eda ◽  
Mari Takizawa ◽  
Toshio Murakami ◽  
Hiroaki Maeda ◽  
Kazuhiko Kimachi ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Cell Epitope ◽  
Sequence Motif ◽  
Clade B ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT An antibody response capable of neutralizing not only homologous but also heterologous forms of the CXCR4-tropic human immunodeficiency virus type 1 (HIV-1) MNp and CCR5-tropic primary isolate HIV-1 JR-CSF was achieved through sequential immunization with a combination of synthetic peptides representing HIV-1 Env V3 sequences from field and laboratory HIV-1 clade B isolates. In contrast, repeated immunization with a single V3 peptide generated antibodies that neutralized only type-specific laboratory-adapted homologous viruses. To determine whether the cross-neutralization response could be attributed to a cross-reactive antibody in the immunized animals, we isolated a monoclonal antibody, C25, which neutralized the heterologous primary viruses of HIV-1 clade B. Furthermore, we generated a humanized monoclonal antibody, KD-247, by transferring the genes of the complementary determining region of C25 into genes of the human V region of the antibody. KD-247 bound with high affinity to the “PGR” motif within the HIV-1 Env V3 tip region, and, among the established reference antibodies, it most effectively neutralized primary HIV-1 field isolates possessing the matching neutralization sequence motif, suggesting its promise for clinical applications involving passive immunizations. These results demonstrate that sequential immunization with B-cell epitope peptides may contribute to a humoral immune-based HIV vaccine strategy. Indeed, they help lay the groundwork for the development of HIV-1 vaccine strategies that use sequential immunization with biologically relevant peptides to overcome difficulties associated with otherwise poorly immunogenic epitopes.

scholarly journals Stoichiometry of Monoclonal Antibody Neutralization of T-Cell Line-Adapted Human Immunodeficiency Virus Type 1

1999 ◽  
Vol 73 (10) ◽  
pp. 8364-8370 ◽  
Author(s):  
Kristian Schønning ◽  
Ole Lund ◽  
Ole Søgaard Lund ◽  
John-Erik Stig Hansen
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Cell Line ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Binding Sites ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT In order to study the stoichiometry of monoclonal antibody (MAb) neutralization of T-cell line-adapted human immunodeficiency virus type 1 (HIV-1) in antibody excess and under equilibrium conditions, we exploited the ability of HIV-1 to generate mixed oligomers when different env genes are coexpressed. By the coexpression of Env glycoproteins that either can or cannot bind a neutralizing MAb in an env transcomplementation assay, virions were generated in which the proportion of MAb binding sites could be regulated. As the proportion of MAb binding sites in Env chimeric virus increased, MAb neutralization gradually increased. Virus neutralization by virion aggregation was minimal, as MAb binding to HIV-1 Env did not interfere with an AMLV Env-mediated infection by HIV-1(AMLV/HIV-1) pseudotypes of CD4− HEK293 cells. MAb neutralization of chimeric virions could be described as a third-order function of the proportion of Env antigen refractory to MAb binding. This scenario is consistent with the Env oligomer constituting the minimal functional unit and neutralization occurring incrementally as each Env oligomer binds MAb. Alternatively, the data could be fit to a sigmoid function. Thus, these data could not exclude the existence of a threshold for neutralization. However, results from MAb neutralization of chimeric virus containing wild-type Env and Env defective in CD4 binding was readily explained by a model of incremental MAb neutralization. In summary, the data indicate that MAb neutralization of T-cell line-adapted HIV-1 is incremental rather than all or none and that each MAb binding an Env oligomer reduces the likelihood of infection.

scholarly journals A Conformation-Specific Monoclonal Antibody Reacting with Fusion-Active gp41 from the Human Immunodeficiency Virus Type 1 Envelope Glycoprotein

1998 ◽  
Vol 72 (12) ◽  
pp. 10213-10217 ◽  
Author(s):  
Shibo Jiang ◽  
Kang Lin ◽  
Min Lu
Keyword(s):  
Monoclonal Antibody ◽  
Human Immunodeficiency Virus ◽  
Membrane Fusion ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Envelope Glycoprotein ◽  
Structural Domain ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The gp41 subunit of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein plays a major role in the membrane fusion step of viral infection. The ectodomain of gp41 contains a six-helix structural domain that likely represents the core of the fusion-active conformation of the molecule. A monoclonal antibody (MAb), designated NC-1, was generated and cloned from a mouse immunized with the model polypeptide N36(L6)C34, which folds into a stable six-helix bundle. NC-1 binds specifically to both the α-helical core domain and the oligomeric forms of gp41. This conformation-dependent reactivity is dramatically reduced by point mutations within the N-terminal coiled-coil region of gp41 which impede formation of the gp41 core. NC-1 binds to the surfaces of HIV-1-infected cells only in the presence of soluble CD4. These results indicate that NC-1 is capable of reacting with fusion-active gp41 in a conformation-specific manner and can be used as a valuable biological reagent for studying the receptor-induced conformational changes in gp41 required for membrane fusion and HIV-1 infection.

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