1
|
Rojas Chávez RA, Boyt D, Schwery N, Han C, Wu L, Haim H. Commonly Elicited Antibodies against the Base of the HIV-1 Env Trimer Guide the Population-Level Evolution of a Structure-Regulating Region in gp41. J Virol 2022; 96:e0040622. [PMID: 35658529 PMCID: PMC9278142 DOI: 10.1128/jvi.00406-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 05/11/2022] [Indexed: 01/28/2023] Open
Abstract
The antibody response against the HIV-1 envelope glycoproteins (Envs) guides evolution of this protein within each host. Whether antibodies with similar target specificities are elicited in different individuals and affect the population-level evolution of Env is poorly understood. To address this question, we analyzed properties of emerging variants in the gp41 fusion peptide-proximal region (FPPR) that exhibit distinct evolutionary patterns in HIV-1 clade B. For positions 534, 536, and 539 in the FPPR, alanine was the major emerging variant. However, 534A and 536A show a constant frequency in the population between 1979 and 2016, whereas 539A is gradually increasing. To understand the basis for these differences, we introduced alanine substitutions in the FPPR of primary HIV-1 strains and examined their functional and antigenic properties. Evolutionary patterns could not be explained by fusion competence or structural stability of the emerging variants. Instead, 534A and 536A exhibited modest but significant increases in sensitivity to antibodies against the membrane-proximal external region (MPER) and gp120-gp41 interface. These Envs were also more sensitive to poorly neutralizing sera from HIV-1-infected individuals than the clade ancestral form or 539A variant. Competition binding assays confirmed for all sera tested the presence of antibodies against the base of the Env trimer that compete with monoclonal antibodies targeting the MPER and gp120-gp41 interface. Our findings suggest that weakly neutralizing antibodies against the trimer base are commonly elicited; they do not exert catastrophic population size reduction effects on emerging variants but, instead, determine their set point frequencies in the population and historical patterns of change. IMPORTANCE Infection by HIV-1 elicits formation of antibodies that target the viral Env proteins and can inactivate the virus. The specific targets of these antibodies vary among infected individuals. It is unclear whether some target specificities are shared among the antibody responses of different individuals. We observed that antibodies against the base of the Env protein are commonly elicited during infection. The selective pressure applied by such antibodies is weak. As a result, they do not completely eliminate the sensitive forms of the virus from the population, but maintain their frequency at a low level that has not increased since the beginning of the AIDS pandemic. Interestingly, the changes in Env do not occur at the sites targeted by the antibodies, but at a distinct region of Env, the fusion peptide-proximal region, which regulates their exposure.
Collapse
Affiliation(s)
- Roberth Anthony Rojas Chávez
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Devlin Boyt
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Nathan Schwery
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Changze Han
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Li Wu
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| | - Hillel Haim
- Department of Microbiology and Immunology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa, USA
| |
Collapse
|
2
|
Zhang C, Huang LS, Zhu R, Meng Q, Zhu S, Xu Y, Zhang H, Fang X, Zhang X, Zhou J, Schooley RT, Yang X, Huang Z, An J. High affinity CXCR4 inhibitors generated by linking low affinity peptides. Eur J Med Chem 2019; 172:174-185. [PMID: 30978562 DOI: 10.1016/j.ejmech.2019.03.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/20/2019] [Accepted: 03/23/2019] [Indexed: 01/04/2023]
Abstract
G-protein coupled receptors (GPCRs) are implicated in many diseases and attractive targets for drug discovery. Peptide fragments derived from protein ligands of GPCRs are commonly used as probes of GPCR function and as leads for drug development. However, these peptide fragments lack the structural integrity of their parent full-length protein ligands and often show low receptor affinity, which limits their research and therapeutic values. It remains a challenge to efficiently generate high affinity peptide inhibitors of GPCRs. We have investigated a combinational approach involving the synthetic covalent linkage of two low affinity peptide fragments to determine if the strategy can yield high affinity GPCR inhibitors. We examined this design approach using the chemokine receptor CXCR4 as a model of GPCR system. Here, we provide a proof of concept demonstration by designing and synthesizing two peptides, AR5 and AR6, that combine a peptide fragment derived from two viral ligands of CXCR4, vMIP-II and HIV-1 envelope glycoprotein gp120. AR5 and AR6 display nanomolar binding affinity, in contrast to the weak micromolar CXCR4 binding of each peptide fragment alone, and inhibit HIV-1 entry via CXCR4. Further studies were carried out for the representative peptide AR6 using western blotting and site-directed mutagenesis in conjunction with molecular dynamic simulation and binding free energy calculation to determine how the peptide interacts with CXCR4 and inhibits its downstream signaling. These results demonstrate that this combinational approach is effective for generating nanomolar active inhibitors of CXCR4 and may be applicable to other GPCRs.
Collapse
Affiliation(s)
- Chaozai Zhang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China
| | - Lina S Huang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; College of Arts and Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Ruohan Zhu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Qian Meng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Siyu Zhu
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; School of Life Sciences, Tsinghua University, Beijing, China
| | - Yan Xu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Huijun Zhang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiong Fang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xingquan Zhang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Jiao Zhou
- Nobel Institute of Biomedicine, Zhuhai, Guangdong, China
| | - Robert T Schooley
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Xiaohong Yang
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China.
| | - Ziwei Huang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA.
| | - Jing An
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA.
| |
Collapse
|
3
|
Neutralizing activity of antibodies to the V3 loop region of HIV-1 gp120 relative to their epitope fine specificity. Virology 2008; 381:251-60. [PMID: 18822440 DOI: 10.1016/j.virol.2008.08.032] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 08/12/2008] [Accepted: 08/15/2008] [Indexed: 11/23/2022]
Abstract
The V3 loop of HIV-1 gp120 is considered occluded on many primary viruses. However, virus sensitivity to neutralization by different V3 mAbs often varies, indicating that access to V3 is not restricted equally for all antibodies. Here, we have sought to gain a better understanding of these restrictions by determining the neutralizing activities of 7 V3 mAbs (19b, 39F, CO11, F2A3, F530, LA21, and LE311) against 15 subtype B primary isolates and relating these activities to the fine specificity of the mAbs. Not surprisingly, we found that most mAbs neutralized the same 2-3 viruses, with only mAb F530 able to neutralize 2 additional viruses not neutralized by the other mAbs. Epitope mapping revealed that positively-charged residues in or near the V3 stem are important for the binding of all the mAbs and that most mAbs seem to require the Pro residue that forms the GPGR beta hairpin turn in the V3 tip for binding. Based on the mapping, we determined that V3 sequence variation accounted for neutralization resistance of approximately half the viruses tested. Comparison of these results to those of select V3 mAbs with overall better neutralizing activities in the light of structural information illustrates how an antibody's mode of interaction with V3, driven by contact residue requirements, may restrict the antibody from accessing its epitope on different viruses. Based on the data we propose an angle of interaction with V3 that is less stringent on access for antibodies with cross-neutralizing activity compared to antibodies that neutralize relatively fewer viruses.
Collapse
|
4
|
Pantophlet R, Aguilar-Sino RO, Wrin T, Cavacini LA, Burton DR. Analysis of the neutralization breadth of the anti-V3 antibody F425-B4e8 and re-assessment of its epitope fine specificity by scanning mutagenesis. Virology 2007; 364:441-53. [PMID: 17418361 PMCID: PMC1985947 DOI: 10.1016/j.virol.2007.03.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2007] [Revised: 02/13/2007] [Accepted: 03/06/2007] [Indexed: 10/23/2022]
Abstract
The identification of cross-neutralizing antibodies to HIV-1 is important for designing antigens aimed at eliciting similar antibodies upon immunization. The monoclonal antibody (mAb) F425-B4e8 had been suggested previously to bind an epitope at the base of V3 and shown to neutralize two primary HIV isolates. Here, we have assessed the neutralization breadth of mAb F425-B4e8 using a 40-member panel of primary HIV-1 and determined the epitope specificity of the mAb. The antibody was able to neutralize 8 clade B viruses (n=16), 1 clade C virus (n=11), and 2 clade D viruses (n=6), thus placing it among the more broadly neutralizing anti-V3 antibodies described so far. Contrary to an initial report, results from our scanning mutagenesis of the V3 region suggest that mAb F425-B4e8 interacts primarily with the crown/tip of V3, notably Ile(309), Arg(315), and Phe(317). Despite the somewhat limited neutralization breadth of mAb F425-B4e8, the results presented here, along with analyses from other cross-neutralizing anti-V3 mAbs, may facilitate the template-based design of antigens that target V3 and permit neutralization of HIV-1 strains in which the V3 region is accessible to antibodies.
Collapse
Affiliation(s)
- Ralph Pantophlet
- The Scripps Research Institute, Department of Immunology, IMM2, La Jolla, CA 92037, USA.
| | | | | | | | | |
Collapse
|
5
|
Hilpert K, Winkler DFH, Hancock REW. Cellulose-bound Peptide Arrays: Preparation and Applications. Biotechnol Genet Eng Rev 2007; 24:31-106. [DOI: 10.1080/02648725.2007.10648093] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
6
|
McCauley SD, Gilchrist M, Befus AD. Regulation and function of the protein inhibitor of nitric oxide synthase (PIN)/dynein light chain 8 (LC8) in a human mast cell line. Life Sci 2006; 80:959-64. [PMID: 17169380 DOI: 10.1016/j.lfs.2006.11.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 11/05/2006] [Accepted: 11/16/2006] [Indexed: 01/17/2023]
Abstract
The protein inhibitor of nitric oxide synthase (PIN) was independently identified as an inhibitor of nitric oxide (NO) produced by neuronal nitric oxide synthase (nNOS), and as a member of the cellular dynein light chain family, dynein light chain 8 (LC8), responsible for intracellular protein trafficking. Mast cells (MC) are involved in several homeostatic and pathological processes and can be regulated by NO. This study describes the expression of PIN/LC8 in the human MC line HMC-1. We also studied if PIN/LC8 binds nNOS, and what role this might have in leukotriene (LT) production. We found that PIN/LC8 mRNA and protein was expressed in HMC-1. Using a GST-PIN construct, we showed PIN binds to nNOS, but not endothelial (e)NOS in HMC-1; in our studies HMC-1 did not express inducible (i)NOS. Intracellular delivery of anti-PIN/LC8 antibody enhanced ionophore (A23187)-induced LT production through an unknown mechanism. Thus we established for the first time expression of PIN/LC8 in human MC, its ability to bind nNOS, and the effect that blocking it has on LT production in a human MC lines.
Collapse
Affiliation(s)
- Scott D McCauley
- Glaxo-Heritage Asthma Research Laboratory, Pulmonary Research Group, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | | | | |
Collapse
|
7
|
Immunogenicity of a polyvalent HIV-1 candidate vaccine based on fourteen wild type gp120 proteins in golden hamsters. BMC Immunol 2006; 7:25. [PMID: 17076905 PMCID: PMC1636068 DOI: 10.1186/1471-2172-7-25] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 10/31/2006] [Indexed: 11/10/2022] Open
Abstract
Background One of the major obstacles in the design of an effective vaccine against HIV-1 is the hypervariability of the HIV-1 envelope glycoprotein. Most HIV-1 vaccine candidates have utilized envelope glycoprotein from a single virus isolate, but to date, none of them elicited broadly reactive humoral immunity. Herein, we hypothesised that a cocktail of HIV-1 gp120 proteins containing multiple epitopes may increase the breadth of immune responses against HIV-1. We compared and evaluated the immunogenicity of HIV-1 vaccines containing either gp120 protein alone or in combinations of four or fourteen gp120s from different primary HIV-1 isolates in immunized hamsters. Results We amplified and characterized 14 different gp120s from primary subtype B isolates with both syncytium and non-syncytium inducing properties, and expressed the proteins in Chinese Hamster Ovary (CHO) cell lines. Purified proteins were used either alone or in combinations of four or fourteen different gp120s to vaccinate golden hamsters. The polyvalent vaccine showed higher antibody titers to HIV-1 subtype B isolates MN and SF162 compared to the groups that received one or four gp120 proteins. However, the polyvalent vaccine was not able to show higher neutralizing antibody responses against HIV-1 primary isolates. Interestingly, the polyvalent vaccine group had the highest proliferative immune responses and showed a substantial proportion of cross-subtype CD4 reactivity to HIV-1 subtypes B, C, and A/E Conclusion Although the polyvalent approach achieved only a modest increase in the breadth of humoral and cellular immunity, the qualitative change in the vaccine (14 vs. 1 gp120) resulted in a quantitative improvement in vaccine-induced immunity.
Collapse
|
8
|
Abstract
The model describing the conformational properties of the HIV-1 principal neutralizing determinant in the geometric space of dihedrals was generated in terms of NMR spectroscopy data published in literature. To gain an object in view, the following successive steps were put into effect: (i) the NMR-based local structures for the HIV(MN) V3 loop were determined in water and in a mixed water/trifluoroethanol (TFE) solvent (7:3), (ii) in either case, the conformations of its irregular segments were analyzed and the secondary structure elements identified, (iii) to appreciate the degree of conformational mobility of the stretch of interest, the simulated structures were compared with each other, (iv) to detect the amino acids retaining their conformations inside the diverse HIV-1 isolates, the structures computed were collated with the one derived previously for the V3 loop from Thailand isolate, and (v) as a matter of record, the structurally rigid residues, that may present the forward-looking targets for AIDS drug researches, were revealed. Summing up the principal results arising from these studies, the following conclusions were drawn: I. The HIV(MN) V3 loop offers the highly mobile fragment of gp120 sensitive to its environment whose changes trigger the large-scale structural reforms, bringing in substantial altering the secondary structure of this functionally important site of the virus envelope. II. In water, it exhibits extended site 1-14 separated by double beta-turn 15-20 with unordered region 21-35. III. Adding the TFE gives rise to destruction of the regular structure in the V3 loop N-terminal, stimulates the formation of 3(10)-helix in site 24-31, and affects also its central region 20-25 forming the HIV-1 immunogenic crown. IV. Regardless of statistically significant differences between local structures of the HIV(MN) V3 loop in water and in water/TFE solution, over one-third of residues keeps their conformational states; the register of these amino acids comprises Asn-25 critical for virus binding with primary cell receptor CD4 as well as Arg-3 critical for utilization of CCR5 coreceptor. V. There are no conserved structural motifs within the V3 loops from Minnesota and Thailand HIV-1 strains. However, perceptible portion of amino acids (more than 35%), including those appearing in the functionally important regions of gp120, holds the values of dihedral angles in which case. The implications are discussed in conjunction with the data on the experimental observations for the HIV-1 principal neutralizing determinant.
Collapse
Affiliation(s)
- A M Andrianov
- Institute of Bioorganic Chemistry, Belarus Academy of Sciences, ac. Kuprevich St., 5/2, 220141 Minsk, Republic of Belarus.
| |
Collapse
|
9
|
Chakrabarti BK, Ling X, Yang ZY, Montefiori DC, Panet A, Kong WP, Welcher B, Louder MK, Mascola JR, Nabel GJ. Expanded breadth of virus neutralization after immunization with a multiclade envelope HIV vaccine candidate. Vaccine 2005; 23:3434-45. [PMID: 15837367 DOI: 10.1016/j.vaccine.2005.01.099] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 12/30/2004] [Accepted: 01/05/2005] [Indexed: 10/25/2022]
Abstract
Although the V3 loop of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) effectively elicits potent neutralizing antibody responses, the specificity of the antibody response is often restricted to T cell line adapted (TCLA) strains and a small subset of primary isolates, limiting its utility for an AIDS vaccine. In this study, we have compared Env immunogens with substituted V3 regions to combinations of strains from different clades and evaluated their ability to expand the breadth of the neutralizing antibody response. When the V3 region from HIV BaL was substituted for HIV HXB2, an effective neutralizing antibody response against several clade B primary isolates was elicited, but it remained restricted to neutralization of most clade B isolates. In an attempt to expand this response further, a linear epitope recognized by the broadly neutralizing 2F5 antibody was inserted into V3. A V3 2F5 epitope was identified that bound to 2F5 and elicited a potent 2F5 antibody response as an immunogen, but the antisera neutralized only a lab-adapted strain and not primary isolates. In contrast, combinations of Envs from clades A, B, and C, elicited neutralizing antibodies to a more diverse group of primary HIV-1 isolates. These studies suggest that combinations of Env immunogens, despite the limited reactivity of the V3 from each component, can be used to expand the breadth of the neutralizing antibody response.
Collapse
Affiliation(s)
- Bimal K Chakrabarti
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 40, Room 4502, MSC 3005, 40 Convent Drive, Bethesda, MD 20892-3005, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Krachmarov C, Pinter A, Honnen WJ, Gorny MK, Nyambi PN, Zolla-Pazner S, Kayman SC. Antibodies that are cross-reactive for human immunodeficiency virus type 1 clade a and clade B v3 domains are common in patient sera from Cameroon, but their neutralization activity is usually restricted by epitope masking. J Virol 2005; 79:780-90. [PMID: 15613306 PMCID: PMC538589 DOI: 10.1128/jvi.79.2.780-790.2005] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Sera from human immunodeficiency virus type 1 (HIV-1)-infected North American patients recognized a fusion protein expressing a V3 loop from a clade B primary isolate virus (JR-CSF) but not from a clade A primary isolate virus (92UG037.8), while most sera from Cameroonian patients recognized both fusion proteins. Competition studies of consensus V3 peptides demonstrated that the majority of the cross-reactive Cameroonian sera contained cross-reactive antibodies that reacted strongly with both V3 sequences. V3-specific antibodies purified from all six cross-reactive sera examined had potent neutralizing activity for virus pseudotyped with envelope proteins (Env) from SF162, a neutralization-sensitive clade B primary isolate. For four of these samples, neutralization of SF162 pseudotypes was blocked by both the clade A and clade B V3 fusion proteins, indicating that this activity was mediated by cross-reactive antibodies. In contrast, the V3-reactive antibodies from only one of these six sera had significant neutralizing activity against viruses pseudotyped with Envs from typically resistant clade B (JR-FL) or clade A (92UG037.8) primary isolates. However, the V3-reactive antibodies from these cross-reactive Cameroonian sera did neutralize virus pseudotyped with chimeric Envs containing the 92UG037.8 or JR-FL V3 sequence in Env backbones that did not express V1/V2 domain masking of V3 epitopes. These data indicated that Cameroonian sera frequently contain cross-clade reactive V3-directed antibodies and indicated that the typical inability of such antibodies to neutralize typical, resistant primary isolate Env pseudotypes was primarily due to indirect masking effects rather than to the absence of the target epitopes.
Collapse
Affiliation(s)
- Chavdar Krachmarov
- Public Health Research Institute, Laboratory of Retroviral Biology, 225 Warren St., Newark, NJ 07103-3535, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Dorgham K, Dogan I, Bitton N, Parizot C, Cardona V, Debré P, Hartley O, Gorochov G. Immunogenicity of HIV type 1 gp120 CD4 binding site phage mimotopes. AIDS Res Hum Retroviruses 2005; 21:82-92. [PMID: 15665647 DOI: 10.1089/aid.2005.21.82] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The conserved domain of the CD4 binding site (CD4bs) on the human immunodeficiency virus type 1 (HIV- 1) envelope represents a potential target for vaccine development. Here we describe selection of peptide mimotopes by panning a phage peptide library on the HIV-1 CD4bs-specific, broadly neutralizing anti-HIV-1 monoclonal antibody, IgG(1) b12. We identified an initial consensus sequence for IgG1 b12 binding (M/VThetaSD, where Theta represents an aromatic amino acid). A molecular evolution approach, using second- and third-generation libraries, led us to identify a refined consensus sequence (GLLVWSDEL). The resulting IgG1 b12 phage mimotopes compete with gp160 for the IgG1 b12 antigen-binding site, but the phage coat protein (pIII) may play an important structural role, since both free peptides and KLH-conjugated peptides have no detectable binding activity. Mice immunized with IgG1 b12 phage mimotopes elicited a weak but persistent humoral response directed against the HIV-1 envelope. An antibody fragment was isolated from the antibody repertoires of these animals. It is noteworthy that while it has a relatively low affinity for HIV-1 gp160, the antibody targets an epitope that overlaps with that of IgG1 b12. Our data therefore suggest that engineered IgG1 b12 mimotopes share immunogenic features with the CD4bs. However, these peptidic structures will require further improvement in order to generate broad specificity neutralizing antibodies like IgG1 b12.
Collapse
Affiliation(s)
- Karim Dorgham
- Immunologie A, CERVI, INSERM U543 and Université Pierre et Marie Curie, Hôpital Pitié-Salpêtrière, 75013 Paris, France
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Andrianov AM. Dual Spatial Folds and Different Local Structures of the HIV-1 Immunogenic Crown in Various Virus Isolates. J Biomol Struct Dyn 2004; 22:159-70. [PMID: 15317477 DOI: 10.1080/07391102.2004.10506992] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Local and global structural properties of the HIV-1 principal neutralizing epitope were studied in terms of NMR spectroscopy data reported in literature for the HIV-Haiti and HIV-RF isolates. To this effect, the NMR-based method comprising a probabilistic model of protein conformation in conjunction with the molecular mechanics and quantum chemical computations was used for determining the ensembles of conformers matching the NMR requirements and energy criteria. As a matter of record, the high resolution 3D structure models were constructed for the HIV-Haiti and HIV-RF immunogenic crowns, and their geometric parameters were collated with the ones of conformers derived previously for describing the conformational features of immunogenic tip of gp120 from Thailand and MN HIV-1 strains. The HIV-1 neutralization site was demonstrated to constitute in water solution highly flexible system sensitive to its environment. This inference is completely valid for the geometric space of dihedral angles where statistically significant differences in local structures of simulated conformers have been found for all virus isolates of interest. In spite of this fact, the stretch analyzed was shown to manifest a certain conservatism in the space of atomic coordinates, building up in four HIV-1 isolates two spatial folds similar to those observed in crystal for the V3 loop peptides bound to different neutralizing Fabs. The results are discussed in the light of literature data on HIV-1 neutralizing epitope structure.
Collapse
Affiliation(s)
- Alexander M Andrianov
- Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Kuprevich St., 5/2, 220141 Minsk, Republic of Belarus.
| |
Collapse
|
13
|
Yang ZY, Chakrabarti BK, Xu L, Welcher B, Kong WP, Leung K, Panet A, Mascola JR, Nabel GJ. Selective modification of variable loops alters tropism and enhances immunogenicity of human immunodeficiency virus type 1 envelope. J Virol 2004; 78:4029-36. [PMID: 15047819 PMCID: PMC374252 DOI: 10.1128/jvi.78.8.4029-4036.2004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although the B clade of human immunodeficiency virus type 1 (HIV-1) envelopes (Env) includes five highly variable regions, each of these domains contains a subset of sequences that remain conserved. The V3 loop has been much studied for its ability to elicit neutralizing antibodies, which are often restricted to a limited number of closely related strains, likely because a large number of antigenic structures are generated from the diverse amino acid sequences in this region. Despite these strain-specific determinants, subregions of V3 are highly conserved, and the effects of different portions of the V3 loop on Env tropism and immunogenicity have not been well delineated. For this report, selective deletions in V3 were introduced by shortening of the stem of the V3 loop. These mutations were explored in combination with deletions of selected V regions. Progressive shortening of the stem of V3 abolished the immunogenicity as well as the functional activity of HIV Env; however, two small deletions on both arms of the V3 stem altered the tropism of the dualtropic 89.6P viral strain so that it infected only CXCR4(+) cells. When this smaller deletion was combined with removal of the V1 and V2 loops and used as an immunogen in guinea pigs, the antisera were able to neutralize multiple independent clade B isolates with a higher potency. These findings suggest that highly conserved subregions within V3 may be relevant targets for eliciting neutralizing antibody responses, affecting HIV tropism, and increasing the immunogenicity of AIDS vaccines.
Collapse
Affiliation(s)
- Zhi-yong Yang
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-3005, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Davis D, Donners H, Willems B, Vermoesen T, Heyndrickx L, Colebunders R, van der Groen G. Epitopes corresponding to the envelope genetic subtype are present on the surface of free virions of HIV-1 group M primary isolates and can be detected in neutralization assays with extended incubation phases. J Med Virol 2003; 71:332-42. [PMID: 12966537 DOI: 10.1002/jmv.10490] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The hypothesis is that there are neutralizing epitopes on the surface of free virions of human immunodeficiency virus type 1 (HIV-1) that correspond to the genetic subtype of the envelope glycoprotein. Assays with extended incubation and reduced absorption phases are required to demonstrate neutralization with antibodies to these epitopes. These assays quantify virus infectivity, rather than reductions in release of antigen into culture supernatants. Neutralizing antibodies reduce virus infectivity by at least 80%, as scored by the presence/absence of antigen released after 14 days in culture of mitogen-transformed peripheral blood mononuclear cells (PBMCs). The epitopes are shared within different subtypes of group M, but not group O, isolates. Individual plasma, selected from three, independent panels of seropositive individuals, cross-neutralize within each subtype as well as the combinations of A with C, B with D or G, and C with CRF01_AE. Isolates within subtype B show the greatest variation in their resistance to neutralization, ranging from highly sensitive to highly resistant. No highly sensitive subtype D isolates were identified. Isolates from subtypes A, C, and CRF01_AE were all resistant. The strategic implication for vaccine design is that antibodies to a limited number of epitopes can neutralize more than 90% of the HIV-1 isolates that are circulating currently in the world. Also, since only antibodies that produce an all-or-nothing loss in virus infectivity can reasonably be expected to prevent the viremic phase after in vivo infection, assays with extended incubation, and culture phases should be used to monitor current efficacy trials.
Collapse
Affiliation(s)
- David Davis
- Department of Microbiology, Virology Unit, Institute of Tropical Medicine, Antwerp, Belgium.
| | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
Mutation in the V3 loop of HIV-1 gp120 could affect syncytium formation, virus infectivity and neutralization. To acquire more information of the V3 loop mutation, we analyzed amino acid sequences of the V3 loop of 24504 isolates from most HIV-1 clades (including A, B, C, D, E, F, G and H clades). The consensus sequence of the V3 loop of each subtype with the highest frequency emerging on each position is constituted and the conservation of each amino acid in this region is also calculated. Exploring the restricted mutation of the V3 region could help to understand mechanism of HIV entry and to develop new strategy against HIV-1.
Collapse
Affiliation(s)
- Haijun Tian
- Laboratory of Immunology, Research Centre for Medical Science and Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing 100084, People's Republic of China
| | | | | |
Collapse
|
16
|
Gorny MK, Williams C, Volsky B, Revesz K, Cohen S, Polonis VR, Honnen WJ, Kayman SC, Krachmarov C, Pinter A, Zolla-Pazner S. Human monoclonal antibodies specific for conformation-sensitive epitopes of V3 neutralize human immunodeficiency virus type 1 primary isolates from various clades. J Virol 2002; 76:9035-45. [PMID: 12186887 PMCID: PMC136433 DOI: 10.1128/jvi.76.18.9035-9045.2002] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The epitopes of the V3 domain of the human immunodeficiency virus type 1 (HIV-1) gp120 glycoprotein have complex structures consisting of linear and conformational antigenic determinants. Anti-V3 antibodies (Abs) recognize both types of elements, but Abs which preferentially react to the conformational aspect of the epitopes may have more potent neutralizing activity against HIV-1, as recently suggested. To test this hypothesis, human anti-V3 monoclonal Abs (MAbs) were selected using a V3 fusion protein (V3-FP) which retains the conformation of the third variable region. The V3-FP consists of the V3(JR-CSF) sequence inserted into a truncated form of murine leukemia virus gp70. Six human MAbs which recognize epitopes at the crown of the V3 loop were selected with the V3-FP. They were found to react more strongly with molecules displaying conformationally intact V3 than with linear V3 peptides. In a virus capture assay, these MAbs showed cross-clade binding to native, intact virions of clades A, B, C, D, and F. No binding was found to isolates from subtype E. The neutralizing activity of MAbs against primary isolates was determined in three assays: the GHOST cell assay, a phytohemagglutinin-stimulated peripheral blood mononuclear cell assay, and a luciferase assay. While these new MAbs displayed various degrees of activity, the pattern of cross-clade neutralization of clades A, B, and F was most pronounced. The neutralization of clades C and D viruses was weak and sporadic, and neutralization of clade E by these MAbs was not detected. Analysis by linear regression showed a highly significant correlation (P < 0.0001) between the strength of binding of these anti-V3 MAbs to intact virions and the percent neutralization. These studies demonstrate that human MAbs to conformation-sensitive epitopes of V3 display cross-clade reactivity in both binding to native, intact virions and neutralization of primary isolates.
Collapse
Affiliation(s)
- Miroslaw K Gorny
- Department of Pathology, New York University School of Medicine, New York, NY 10016, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Hofmann-Lehmann R, Vlasak J, Chenine AL, Li PL, Baba TW, Montefiori DC, McClure HM, Anderson DC, Ruprecht RM. Molecular evolution of human immunodeficiency virus env in humans and monkeys: similar patterns occur during natural disease progression or rapid virus passage. J Virol 2002; 76:5278-84. [PMID: 11967343 PMCID: PMC136137 DOI: 10.1128/jvi.76.10.5278-5284.2002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Neonatal rhesus macaque 95-3 was inoculated with nonpassaged simian-human immunodeficiency virus strain SHIV-vpu(+), which encodes env of the laboratory-adapted human immunodeficiency virus (HIV) strain IIIB and is considered nonpathogenic. CD4(+) T-cell counts dropped to <200 cells/microl within 4.6 years, and monkey 95-3 died with opportunistic infections 5.9 years postinoculation. Transfer of blood from 95-3 to two naive adult macaques resulted in high peak viral loads and rapid, persistent T-cell depletion. Progeny virus evolved in 95-3 despite high SHIV-vpu(+) neutralizing antibody titers and still used CXCR4 but, in contrast to parental SHIV-vpu(+), productively infected macrophages and resisted neutralization. Sequence analysis revealed three new potential glycosylation sites in gp120; another two were lost. Strikingly similar mutations were detected in a laboratory worker who progressed to AIDS after accidental HIV-IIIB infection (T. Beaumont et al., J. Virol. 75:2246-2252, 2001), thus supporting the SHIV-vpu(+)/rhesus macaque system as a relevant model. Similar mutations were also described after rapid passage of chimeric viruses encoding IIIB env in rhesus and pig-tailed macaques (M. Cayabyab et al., J. Virol. 73:976-984, 1999; Z. Q. Liu et al., Virology 260:295-307, 1999; S. V. Narayan et al., Virology 256:54-63, 1999; R. Raghavan et al., Brain Pathol. 7:851-861, 1997; E. B. Stephens et al., Virology 231:313-321, 1997). Thus, HIV-IIIB env evolved similarly in three different species; this selection occurred in chronically infected individuals during disease progression as well as after rapid virus passage. We postulate that evolutionary pressure led to the outgrowth of more aggressive viral variants in all three species.
Collapse
Affiliation(s)
- Regina Hofmann-Lehmann
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115-6084, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Krachmarov CP, Kayman SC, Honnen WJ, Trochev O, Pinter A. V3-specific polyclonal antibodies affinity purified from sera of infected humans effectively neutralize primary isolates of human immunodeficiency virus type 1. AIDS Res Hum Retroviruses 2001; 17:1737-48. [PMID: 11788025 DOI: 10.1089/08892220152741432] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although many human sera possess potent neutralizing activities for primary HIV-1 viruses, such activities are not efficiently induced by the current generation of vaccine candidates, and the epitopes mediating this neutralization are not known. The V3 loop of gp120 is believed to be the principal neutralization domain of laboratory-adapted viruses, but the importance of this region in neutralization of primary isolates is unclear. This question was explored using polyclonal anti-V3 antibodies purified by immunoaffinity methods from sera of HIV-1-infected patients. To include antibodies that might be directed against conformational and/or glycan-dependent epitopes not presented by synthetic peptides, the antibody isolations were performed with a fusion glycoprotein expressing the native V3 region of JR-CSF, a primary R5 isolate. V3-reactive antibody fractions from all eight sera examined showed potent neutralization of at least one of the three primary HIV-1 isolates tested; four of these antibody preparations neutralized all three primary viruses. For a number of serum-virus combinations 90% neutralization doses (ND(90)) between 1 and 5 microg/ml were obtained, and the most potent anti-V3 fraction had ND(50) values at or below 0.3 microg/ml for all three primary isolates. These neutralization activities against primary viruses were higher than those of potent monoclonal antibodies assayed in the same experiment. These data indicate that the V3 region can be an important neutralization target in primary isolates, and suggest that effective presentation of V3 epitopes in a vaccine formulation might induce protective humoral responses against natural infection by HIV-1.
Collapse
Affiliation(s)
- C P Krachmarov
- Laboratory of Retroviral Biology, Public Health Research Institute, New York, New York 10016, USA
| | | | | | | | | |
Collapse
|
19
|
Chen CH, Jin L, Zhu C, Holz-Smith S, Matthews TJ. Induction and characterization of neutralizing antibodies against a human immunodeficiency virus type 1 primary isolate. J Virol 2001; 75:6700-4. [PMID: 11413338 PMCID: PMC114394 DOI: 10.1128/jvi.75.14.6700-6704.2001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chimpanzees infected with the primary isolate DH012 mount potent neutralizing antibodies. This DH012 neutralizing activity is highly strain specific. Immune sera from guinea pigs immunized with recombinant DH012 gp120 could also neutralize this primary isolate. The neutralizing activity in chimpanzee and guinea pig sera against wild-type DH012 appears to be independent of a linear epitope in the V3 region of gp120. Interestingly, the neutralization escape mutant derived from growing DH012 in the presence of the potent neutralizing chimpanzee serum is at least 50-fold more sensitive than wild-type DH012 to neutralization by guinea pig immune sera. The unusually potent neutralizing activity against the DH012 neutralization-resistant virus is due to the presence of anti-V3 antibodies in guinea pig sera. These results suggested that recombinant gp120 could induce neutralizing antibodies against primary isolate DH012. The V3 of wild-type DH012 is poorly immunogenic in infected chimpanzees and is not accessible to neutralizing V3 antibodies. It is likely that this cryptic V3 region became exposed when the virus escaped the neutralizing activity of the chimpanzee serum.
Collapse
Affiliation(s)
- C H Chen
- Department of Microbiology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, Tennessee 37208, USA.
| | | | | | | | | |
Collapse
|
20
|
Vranken WF, Fant F, Budesinsky M, Borremans FA. Conformational model for the consensus V3 loop of the envelope protein gp120 of HIV-1 in a 20% trifluoroethanol/water solution. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:2620-8. [PMID: 11322882 DOI: 10.1046/j.1432-1327.2001.02146.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Based on experimental NMR data, a model was generated for the conformation of the disulfide-bond-closed cyclic peptide corresponding to the whole V3 loop of the consensus HIV-1 strain in a 20% trifluoroethanol/water solution. The obtained family of structures shows a prominent and well-defined amphipathic alpha helix at the C-terminal end of the peptide from Thr23 to Gln32. A series of turns characterizes the central Gly15-Tyr21 region, while the N-terminal region is poorly defined. Independent experimental data confirms the features of this model, and suggests that this type of conformation can be readily adopted when the V3 loop is in contact with a membrane. The examined V3 loop belongs to a macrophage tropic strain, and using the model, a structural explanation is proposed for the different requirements of V3 loops belonging to macrophage and T-cell line tropic HIV-1 strains.
Collapse
Affiliation(s)
- W F Vranken
- BioNMR and Peptide Synthesis, Department of Organic Chemistry, Ghent University, Belgium; Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | | | | | | |
Collapse
|
21
|
Nyambi PN, Nádas A, Mbah HA, Burda S, Williams C, Gorny MK, Zolla-Pazner S. Immunoreactivity of intact virions of human immunodeficiency virus type 1 (HIV-1) reveals the existence of fewer HIV-1 immunotypes than genotypes. J Virol 2000; 74:10670-80. [PMID: 11044111 PMCID: PMC110941 DOI: 10.1128/jvi.74.22.10670-10680.2000] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In order to protect against organisms that exhibit significant genetic variation, polyvalent vaccines are needed. Given the extreme variability of human immunodeficiency virus type 1 (HIV-1), it is probable that a polyvalent vaccine will also be needed for protection from this virus. However, to understand how to construct a polyvalent vaccine, serotypes or immunotypes of HIV must be identified. In the present study, we have examined the immunologic relatedness of intact, native HIV-1 primary isolates of group M, clades A to H, with human monoclonal antibodies (MAbs) directed at epitopes in the V3, C5, and gp41 cluster I regions of the envelope glycoproteins, since these regions are well exposed on the virion surface. Multivariate analysis of the binding data revealed three immunotypes of HIV-1 and five MAb groups useful for immunotyping of the viruses. The analysis revealed that there are fewer immunotypes than genotypes of HIV and that clustering of the isolates did not correlate with either genotypes, coreceptor usage (CCR5 and CXCR4), or geographic origin of the isolates. Further analysis revealed distinct MAb groups that bound preferentially to HIV-1 isolates belonging to particular immunotypes or that bound to all three immunotypes; this demonstrates that viral immunotypes identified by mathematical analysis are indeed defined by their immunologic characteristics. In summary, these results indicate (i) that HIV-1 immunotypes can be defined, (ii) that constellations of epitopes that are conserved among isolates belonging to each individual HIV-1 immunotype exist and that these distinguish each of the immunotypes, and (iii) that there are also epitopes that are routinely shared by all immunotypes.
Collapse
Affiliation(s)
- P N Nyambi
- Department of Pathology, New York University School of Medicine, New York, New York 10016, USA
| | | | | | | | | | | | | |
Collapse
|
22
|
Wobus CE, Hügle-Dörr B, Girod A, Petersen G, Hallek M, Kleinschmidt JA. Monoclonal antibodies against the adeno-associated virus type 2 (AAV-2) capsid: epitope mapping and identification of capsid domains involved in AAV-2-cell interaction and neutralization of AAV-2 infection. J Virol 2000; 74:9281-93. [PMID: 10982375 PMCID: PMC102127 DOI: 10.1128/jvi.74.19.9281-9293.2000] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The previously characterized monoclonal antibodies (MAbs) A1, A69, B1, and A20 are directed against assembled or nonassembled adeno-associated virus type 2 (AAV-2) capsid proteins (A. Wistuba, A. Kern, S. Weger, D. Grimm, and J. A. Kleinschmidt, J. Virol. 71:1341-1352, 1997). Here we describe the linear epitopes of A1, A69, and B1 which reside in VP1, VP2, and VP3, respectively, using gene fragment phage display library, peptide scan, and peptide competition experiments. In addition, MAbs A20, C24-B, C37-B, and D3 directed against conformational epitopes on AAV-2 capsids were characterized. Epitope sequences on the capsid surface were identified by enzyme-linked immunoabsorbent assay using AAV-2 mutants and AAV serotypes, peptide scan, and peptide competition experiments. A20 neutralizes infection following receptor attachment by binding an epitope formed during AAV-2 capsid assembly. The newly isolated antibodies C24-B and C37-B inhibit AAV-2 binding to cells, probably by recognizing a loop region involved in binding of AAV-2 to the cellular receptor. In contrast, binding of D3 to a loop near the predicted threefold spike does not neutralize AAV-2 infection. The identified antigenic regions on the AAV-2 capsid surface are discussed with respect to their possible roles in different steps of the viral life cycle.
Collapse
Affiliation(s)
- C E Wobus
- Forschungsschwerpunkt Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Germany
| | | | | | | | | | | |
Collapse
|
23
|
Carlos MP, Anderson DE, Gardner MB, Torres JV. Immunogenicity of a vaccine preparation representing the variable regions of the HIV type 1 envelope glycoprotein. AIDS Res Hum Retroviruses 2000; 16:153-61. [PMID: 10659054 DOI: 10.1089/088922200309494] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
Variability of the major antigenic sites of the envelope glycoprotein of HIV-1 constitutes a major problem in the formulation of effective vaccines. We have prepared a synthetic peptide vaccine that represents the major hypervariable epitopes (V1 through V5) of the clade B HIV-1 envelope glycoprotein (gp120). We refer to this preparation as variable epitope immunogen or VEI vaccine. This construct takes into consideration the type and frequency of amino acid substitutions found at each epitope during the evolution of the virus in individual patients and in the target population. Immunization of mice, rabbits, and rhesus macaques with the VEI vaccine resulted in the induction of long-lasting, high-titered HIV-1 antibodies, including antibodies that neutralize primary isolates. We also documented lymphocyte proliferative responses to the VEI vaccine, its individual components, analogs, and subtype-specific peptides representing the major hypervariable regions of HIV-1 gp120. Delayed-type hypersensitivity responses to these antigens were also demonstrated in mice. Our results show that this vaccine is highly immunogenic and safe in animals. Our data suggest that this formulation could become an important component of combination vaccine approaches against HIV-1 and other antigenically variable pathogens.
Collapse
Affiliation(s)
- M P Carlos
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis 95616, USA
| | | | | | | |
Collapse
|
24
|
Kramer A, Reineke U, Dong L, Hoffmann B, Hoffmüller U, Winkler D, Volkmer-Engert R, Schneider-Mergener J. Spot synthesis: observations and optimizations. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 1999; 54:319-27. [PMID: 10532237 DOI: 10.1034/j.1399-3011.1999.00108.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Positionally addressable syntheses of peptides on continuous cellulose membranes (spot synthesis) have often been reported in detail, but important questions dealing with synthesis quality, reproducibility and subsequent binding assays have largely been under-emphasized. In this report we have investigated some of these problems. The most important results were: (i) the signal intensity of ligate binding to cellulose-bound peptides and the affinity of the corresponding soluble peptides show good correlation, illustrated by three different ligate binding assays; (ii) reducing peptide density on the cellulose avoids the 'ring spot' effect, i.e. where less binding is observed in the spot-center compared to the rim. We recommend a peptide density of 10 nmol/cm2 as a reasonable starting point for further optimization; (iii) statistical analysis of binding assay reproducibility with more than 15000 peptides resulted in a mean standard signal deviation of 0.18; and (iv) optimization of side-chain deprotection revealed that a 30-min pretreatment of the cellulose with 90% trifluoroacetic acid followed by the standard deprotection protocol resulted in higher purity of the synthesized products.
Collapse
Affiliation(s)
- A Kramer
- Institut für Medizinische Immunologie, Universitätsklinikum Charité, Humboldt-Universität zu Berlin, Germany
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Skraban R, Matthíasdóttir S, Torsteinsdóttir S, Agnarsdóttir G, Gudmundsson B, Georgsson G, Meloen RH, Andrésson OS, Staskus KA, Thormar H, Andrésdóttir V. Naturally occurring mutations within 39 amino acids in the envelope glycoprotein of maedi-visna virus alter the neutralization phenotype. J Virol 1999; 73:8064-72. [PMID: 10482555 PMCID: PMC112822 DOI: 10.1128/jvi.73.10.8064-8072.1999] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/1999] [Accepted: 06/25/1999] [Indexed: 11/20/2022] Open
Abstract
Infectious molecular clones have been isolated from two maedi-visna virus (MVV) strains, one of which (KV1772kv72/67) is an antigenic escape mutant of the other (LV1-1KS1). To map the type-specific neutralization epitope, we constructed viruses containing chimeric envelope genes by using KV1772kv72/67 as a backbone and replacing various parts of the envelope gene with equivalent sequences from LV1-1KS1. The neutralization phenotype was found to map to a region in the envelope gene containing two deletions and four amino acid changes within 39 amino acids (positions 559 to 597 of Env). Serum obtained from a lamb infected with a chimeric virus, VR1, containing only the 39 amino acids from LV1-1KS1 in the KV1772kv72/67 backbone neutralized LV1-1KS1 but not KV1772kv72/67. The region in the envelope gene that we had thus shown to be involved in escape from neutralization was cloned into pGEX-3X expression vectors, and the resulting fusion peptides from both molecular clones were tested in immunoblots for reactivity with the KV1772kv72/67 and VR1 type-specific antisera. The type-specific KV1772kv72/67 antiserum reacted only with the fusion peptide from KV1772kv72/67 and not with that from LV1-1KS1, and the type-specific VR1 antiserum reacted only with the fusion peptide from LV1-1KS1 and not with that from KV1772kv72/67. Pepscan analysis showed that the region contained two linear epitopes, one of which was specific to each of the molecularly cloned viruses. This linear epitope was not bound by all type-specific neutralizing antisera, however, which indicates that it is not by itself the neutralization epitope but may be a part of it. These findings show that mutations within amino acids 559 to 597 in the envelope gene of MVV virus result in escape from neutralization. Furthermore, the region contains one or more parts of a discontinuous neutralization epitope.
Collapse
Affiliation(s)
- R Skraban
- Institute for Experimental Pathology, University of Iceland, Keldur, Iceland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Lawoko A, Johansson B, Hjalmarsson S, Christensson B, Ljungberg B, Al-Khalili L, Sj�lund M, Pipkorn R, Feny� E, Blomberg J. Comparative studies on neutralisation of primary HIV-1 isolates by human sera and rabbit anti-V3 peptide sera. J Med Virol 1999. [DOI: 10.1002/(sici)1096-9071(199910)59:2<169::aid-jmv8>3.0.co;2-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
27
|
Metlas R, Trajkovic D, Srdic T, Veljkovic V, Colombatti A. Human immunodeficiency virus V3 peptide-reactive antibodies are present in normal HIV-negative sera. AIDS Res Hum Retroviruses 1999; 15:671-7. [PMID: 10331446 DOI: 10.1089/088922299310971] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A structural relation between consensus sequences of the portion of HIV-1 gp120 involving the V3 loop (V3 peptide) and the variable domains of human immunoglobulin members of the VH-III gene family was proposed to trigger an imbalance of the idiotypic network during the course of HIV infection. Thus, the repertoires of immunoglobulins in healthy individuals should contain antigenic determinant(s) complementary to particular V3 loop epitope(s). In this study we investigated the specific binding to the V3 peptide of antibodies present in sera of HIV-positive and of clinically normal HIV-negative subjects. Two groups of HIV-positive sera differing in antibody titers to V3 peptide, arbitrarily referred here as high- and low-reactive HIV-positive sera, were distinguished on the basis of an ELISA. Antibodies were affinity purified on V3 peptide and their titers in both HIV-negative and low-reactive HIV-positive sera were nearly superimposable and much lower than the titers of those from high-reactive HIV-positive sera. Also, the quality of the two groups of antibodies differed: much higher amounts of soluble V3 peptide were needed to partly compete the binding of antibodies from HIV-negative sera to insoluble V3 peptide as compared with those from HIV-positive sera, suggesting that the latter had higher affinity for V3 peptide. All of the affinity-purified antibodies bound poorly to unrelated peptides, even to those sharing sequence similarity with the V3 peptide. The present observations suggest that in HIV infection antigen-driven affinity maturation of preimmune immunoglobulins with idiotypes complementary to V3 epitope(s) participating in physiological autoreactivity might be at work.
Collapse
Affiliation(s)
- R Metlas
- R&D Division, Diapharm, Belgrade, Yugoslavia
| | | | | | | | | |
Collapse
|
28
|
Narayan SV, Mukherjee S, Jia F, Li Z, Wang C, Foresman L, McCormick-Davis C, Stephens EB, Joag SV, Narayan O. Characterization of a neutralization-escape variant of SHIVKU-1, a virus that causes acquired immune deficiency syndrome in pig-tailed macaques. Virology 1999; 256:54-63. [PMID: 10087226 DOI: 10.1006/viro.1999.9605] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A chimeric simian-human immunodeficiency virus (SHIV-4) containing the tat, rev, vpu, and env genes of HIV type 1 (HIV-1) in a genetic background of SIVmac239 was used to develop an animal model in which a primate lentivirus expressing the HIV-1 envelope glycoprotein caused acquired immune deficiency syndrome (AIDS) in macaques. An SHIV-infected pig-tailed macaque that died from AIDS at 24 weeks postinoculation experienced two waves of viremia: one extending from weeks 2-8 and the second extending from week 18 until death. Virus (SHIVKU-1) isolated during the first wave was neutralized by antibodies appearing at the end of the first viremic phase, but the virus (SHIVKU-1b) isolated during the second viremic phase was not neutralized by these antibodies. Inoculation of SHIVKU-1b into 4 pig-tailed macaques resulted in severe CD4(+) T cell loss by 2 weeks postinoculation, and all 4 macaques died from AIDS at 23-34 weeks postinoculation. Because this virus had a neutralization-resistant phenotype, we sequenced the env gene and compared these sequences with those of the env gene of SHIVKU-1 and parental SHIV-4. With reference to SHIV-4, SHIVKU-1b had 18 and 6 consensus amino acid substitutions in the gp120 and gp41 regions of Env, respectively. These compared with 10 and 3 amino acid substitutions in the gp120 and gp41 regions of SHIVKU-1. Our data suggested that SHIVKU-1 and SHIVKU-1b probably evolved from a common ancestor but that SHIVKU-1b did not evolve from SHIVKU-1. A chimeric virus, SHIVKU-1bMC17, constructed with the consensus env from the SHIVKU-1b on a background of SHIV-4, confirmed that amino acid substitutions in Env were responsible for the neutralization-resistant phenotype. These results are consistent with the hypothesis that neutralizing antibodies induced by SHIVKU-1 in pig-tailed macaque resulted in the selection of a neutralization-resistant virus that was responsible for the second wave of viremia.
Collapse
Affiliation(s)
- S V Narayan
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, Kansas 66160-7420, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Spenlehauer C, Saragosti S, Fleury HJ, Kirn A, Aubertin AM, Moog C. Study of the V3 loop as a target epitope for antibodies involved in the neutralization of primary isolates versus T-cell-line-adapted strains of human immunodeficiency virus type 1. J Virol 1998; 72:9855-64. [PMID: 9811721 PMCID: PMC110497 DOI: 10.1128/jvi.72.12.9855-9864.1998] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies characterized the third variable (V3) loop of the envelope gp120 as the principal neutralizing determinant for laboratory T-cell-line-adapted (TCLA) strains of human immunodeficiency virus type 1 (HIV-1). However, primary viruses isolated from infected individuals are more refractory to neutralization than TCLA strains, suggesting that qualitatively different neutralizing antibodies may be involved. In this study, we investigated whether the V3 loop constitutes a linear target epitope for antibodies neutralizing primary isolates. By using peptides representative of the V3 regions of various primary isolates, an early, relatively specific and persistent antibody response was detected in sera from HIV-infected patients. To assess the relationship between these antibodies and neutralization, the same peptides were used in competition and depletion experiments. Addition of homologous V3 peptides led to a competitive inhibition in the neutralization of the TCLA strain HIVMN/MT-4 but had no effect on the neutralization of the autologous primary isolate. Similarly, the removal of antibodies that bind to linear V3 epitopes resulted in a loss of HIVMN/MT-4 neutralization, whereas no decrease in the autologous neutralization was measured. The different roles of V3-specific antibodies according to the virus considered were thereby brought to light. This confirmed the involvement of V3 antibodies in the neutralization of a TCLA strain but emphasized a more pronounced contribution of either conformational epitopes or epitopes outside the V3 loop as targets for antibodies neutralizing primary HIV-1 isolates. This result underlines the need to focus on new vaccinal immunogens with epitopes able to induce broadly reactive and efficient antibodies that neutralize a wide range of primary HIV-1 isolates.
Collapse
Affiliation(s)
- C Spenlehauer
- INSERM U74, Institut de Virologie, 67000 Strasbourg, France
| | | | | | | | | | | |
Collapse
|