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HIV-1 Env DNA vaccine plus protein boost delivered by EP expands B- and T-cell responses and neutralizing phenotype in vivo. PLoS One 2013; 8:e84234. [PMID: 24391921 PMCID: PMC3877240 DOI: 10.1371/journal.pone.0084234] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 11/13/2013] [Indexed: 02/07/2023] Open
Abstract
An effective HIV vaccine will most likely require the induction of strong T-cell responses, broadly neutralizing antibodies (bNAbs), and the elicitation of antibody-dependent cellular cytotoxicity (ADCC). Previously, we demonstrated the induction of strong HIV/SIV cellular immune responses in macaques and humans using synthetic consensus DNA immunogens delivered via adaptive electroporation (EP). However, the ability of this improved DNA approach to prime for relevant antibody responses has not been previously studied. Here, we investigate the immunogenicity of consensus DNA constructs encoding gp140 sequences from HIV-1 subtypes A, B, C and D in a DNA prime-protein boost vaccine regimen. Mice and guinea pigs were primed with single- and multi-clade DNA via EP and boosted with recombinant gp120 protein. Sera were analyzed for gp120 binding and induction of neutralizing antibody activity. Immunization with recombinant Env protein alone induced low-titer binding antibodies with limited neutralization breath. In contrast, the synthetic DNA prime-protein boost protocol induced significantly higher antibody binding titers. Furthermore, sera from DNA prime-protein boost groups were able to neutralize a broader range of viruses in a panel of tier 1 clade B viruses as well as multiple tier 1 clade A and clade C viruses. Further investigation of synthetic DNA prime plus adaptive EP plus protein boost appears warranted.
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Roitburd-Berman A, Dela G, Kaplan G, Lewis GK, Gershoni JM. Allosteric induction of the CD4-bound conformation of HIV-1 Gp120. Retrovirology 2013; 10:147. [PMID: 24304511 PMCID: PMC4235218 DOI: 10.1186/1742-4690-10-147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 11/25/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND HIV-1 infection of target cells is mediated via the binding of the viral envelope protein, gp120, to the cell surface receptor CD4. This interaction leads to conformational rearrangements in gp120 forming or revealing CD4 induced (CD4i) epitopes which are critical for the subsequent recognition of the co-receptor required for viral entry. The CD4-bound state of gp120 has been considered a potential immunogen for HIV-1 vaccine development. Here we report on an alternative means to induce gp120 into the CD4i conformation. RESULTS Combinatorial phage display peptide libraries were screened against HIV-1 gp120 and short (14aa) peptides were selected that bind the viral envelope and allosterically induce the CD4i conformation. The lead peptide was subsequently systematically optimized for higher affinity as well as more efficient inductive activity. The peptide:gp120 complex was scrutinized with a panel of neutralizing anti-gp120 monoclonal antibodies and CD4 itself, illustrating that peptide binding does not interfere with or obscure the CD4 binding site. CONCLUSIONS Two surfaces of gp120 are considered targets for the development of cross neutralizing antibodies against HIV-1; the CD4 binding site and CD4i epitopes. By implementing novel peptides that allosterically induce the CD4i epitopes we have generated a viral envelope that presents both of these surfaces simultaneously.
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Affiliation(s)
| | | | | | | | - Jonathan M Gershoni
- Department of Cell Research and Immunology, George S, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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Pissani F, Malherbe DC, Schuman JT, Robins H, Park BS, Krebs SJ, Barnett SW, Haigwood NL. Improvement of antibody responses by HIV envelope DNA and protein co-immunization. Vaccine 2013; 32:507-13. [PMID: 24280279 DOI: 10.1016/j.vaccine.2013.11.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 10/29/2013] [Accepted: 11/06/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Developing HIV envelope (Env) vaccine components that elicit durable and protective antibody responses is an urgent priority, given the results from the RV144 trial. Optimization of both the immunogens and vaccination strategies will be needed to generate potent, durable antibodies. Due to the diversity of HIV, an effective Env-based vaccine will most likely require an extensive coverage of antigenic variants. A vaccine co-delivering Env immunogens as DNA and protein components could provide such coverage. Here, we examine a DNA and protein co-immunization strategy by characterizing the antibody responses and evaluating the relative contribution of each vaccine component. METHOD We co-immunized rabbits with representative subtype A or B HIV gp160 plasmid DNA plus Env gp140 trimeric glycoprotein and compared the responses to those obtained with either glycoprotein alone or glycoprotein in combination with empty vector. RESULTS DNA and glycoprotein co-immunization was superior to immunization with glycoprotein alone by enhancing antibody kinetics, magnitude, avidity, and neutralizing potency. Importantly, the empty DNA vector did not contribute to these responses. Humoral responses elicited by mismatched DNA and protein components were comparable or higher than the responses produced by the matched vaccines. CONCLUSION Our data show that co-delivering DNA and protein can augment antibodies to Env. The rate and magnitude of immune responses suggest that this approach has the potential to streamline vaccine regimens by inducing higher antibody responses using fewer vaccinations, an advantage for a successful HIV vaccine design.
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Affiliation(s)
- Franco Pissani
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97217, United States; The Vaccine and Gene Therapy Institute, Beaverton, OR 97006, United States; Oregon National Primate Research Center, Beaverton, OR 97006, United States
| | | | - Jason T Schuman
- GE Healthcare, Life Sciences, Piscataway, NJ 08854, United States
| | - Harlan Robins
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, United States
| | - Byung S Park
- Oregon National Primate Research Center, Beaverton, OR 97006, United States; Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland, OR 97239, United States
| | - Shelly J Krebs
- The Vaccine and Gene Therapy Institute, Beaverton, OR 97006, United States; Oregon National Primate Research Center, Beaverton, OR 97006, United States
| | - Susan W Barnett
- Novartis Institutes for Biomedical Research, Cambridge, MA 02139, United States
| | - Nancy L Haigwood
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97217, United States; The Vaccine and Gene Therapy Institute, Beaverton, OR 97006, United States; Oregon National Primate Research Center, Beaverton, OR 97006, United States.
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54
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Barouch DH, Stephenson KE, Borducchi EN, Smith K, Stanley K, McNally AG, Liu J, Abbink P, Maxfield LF, Seaman MS, Dugast AS, Alter G, Ferguson M, Li W, Earl PL, Moss B, Giorgi EE, Szinger JJ, Eller LA, Billings EA, Rao M, Tovanabutra S, Sanders-Buell E, Weijtens M, Pau MG, Schuitemaker H, Robb ML, Kim JH, Korber BT, Michael NL. Protective efficacy of a global HIV-1 mosaic vaccine against heterologous SHIV challenges in rhesus monkeys. Cell 2013; 155:531-9. [PMID: 24243013 DOI: 10.1016/j.cell.2013.09.061] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/05/2013] [Accepted: 09/27/2013] [Indexed: 01/24/2023]
Abstract
The global diversity of HIV-1 represents a critical challenge facing HIV-1 vaccine development. HIV-1 mosaic antigens are bioinformatically optimized immunogens designed for improved coverage of HIV-1 diversity. However, the protective efficacy of such global HIV-1 vaccine antigens has not previously been evaluated. Here, we demonstrate the capacity of bivalent HIV-1 mosaic antigens to protect rhesus monkeys against acquisition of infection following heterologous challenges with the difficult-to-neutralize simian-human immunodeficiency virus SHIV-SF162P3. Adenovirus/poxvirus and adenovirus/adenovirus vector-based vaccines expressing HIV-1 mosaic Env, Gag, and Pol afforded a significant reduction in the per-exposure acquisition risk following repetitive, intrarectal SHIV-SF162P3 challenges. Protection against acquisition of infection correlated with vaccine-elicited binding, neutralizing, and functional nonneutralizing antibodies, suggesting that the coordinated activity of multiple antibody functions may contribute to protection against difficult-to-neutralize viruses. These data demonstrate the protective efficacy of HIV-1 mosaic antigens and suggest a potential strategy for the development of a global HIV-1 vaccine. PAPERCLIP:
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Affiliation(s)
- Dan H Barouch
- Center for Virology and Vaccine Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA; Ragon Institute of MGH, Massachusetts Institute of Technology and Harvard, Boston, MA 02114, USA.
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A next-generation cleaved, soluble HIV-1 Env trimer, BG505 SOSIP.664 gp140, expresses multiple epitopes for broadly neutralizing but not non-neutralizing antibodies. PLoS Pathog 2013; 9:e1003618. [PMID: 24068931 PMCID: PMC3777863 DOI: 10.1371/journal.ppat.1003618] [Citation(s) in RCA: 740] [Impact Index Per Article: 67.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 07/30/2013] [Indexed: 01/17/2023] Open
Abstract
A desirable but as yet unachieved property of a human immunodeficiency virus type 1 (HIV-1) vaccine candidate is the ability to induce broadly neutralizing antibodies (bNAbs). One approach to the problem is to create trimeric mimics of the native envelope glycoprotein (Env) spike that expose as many bNAb epitopes as possible, while occluding those for non-neutralizing antibodies (non-NAbs). Here, we describe the design and properties of soluble, cleaved SOSIP.664 gp140 trimers based on the subtype A transmitted/founder strain, BG505. These trimers are highly stable, more so even than the corresponding gp120 monomer, as judged by differential scanning calorimetry. They are also homogenous and closely resemble native virus spikes when visualized by negative stain electron microscopy (EM). We used several techniques, including ELISA and surface plasmon resonance (SPR), to determine the relationship between the ability of monoclonal antibodies (MAbs) to bind the soluble trimers and neutralize the corresponding virus. In general, the concordance was excellent, in that virtually all bNAbs against multiple neutralizing epitopes on HIV-1 Env were highly reactive with the BG505 SOSIP.664 gp140 trimers, including quaternary epitopes (CH01, PG9, PG16 and PGT145). Conversely, non-NAbs to the CD4-binding site, CD4-induced epitopes or gp41ECTO did not react with the trimers, even when their epitopes were present on simpler forms of Env (e.g. gp120 monomers or dissociated gp41 subunits). Three non-neutralizing MAbs to V3 epitopes did, however, react strongly with the trimers but only by ELISA, and not at all by SPR and to only a limited extent by EM. These new soluble trimers are useful for structural studies and are being assessed for their performance as immunogens.
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56
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Heyndrickx L, Stewart-Jones G, Jansson M, Schuitemaker H, Bowles E, Buonaguro L, Grevstad B, Vinner L, Vereecken K, Parker J, Ramaswamy M, Biswas P, Vanham G, Scarlatti G, Fomsgaard A. Selected HIV-1 Env trimeric formulations act as potent immunogens in a rabbit vaccination model. PLoS One 2013; 8:e74552. [PMID: 24023951 PMCID: PMC3759472 DOI: 10.1371/journal.pone.0074552] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 08/04/2013] [Indexed: 01/12/2023] Open
Abstract
Background Ten to 30% of HIV-1 infected subjects develop broadly neutralizing antibodies (bNAbs) during chronic infection. We hypothesized that immunizing rabbits with viral envelope glycoproteins (Envs) from these patients may induce bNAbs, when formulated as a trimeric protein and in the presence of an adjuvant. Methods Based on in vitro neutralizing activity in serum, patients with bNAbs were selected for cloning of their HIV-1 Env. Seven stable soluble trimeric gp140 proteins were generated from sequences derived from four adults and two children infected with either clade A or B HIV-1. From one of the clade A Envs both the monomeric and trimeric Env were produced for comparison. Rabbits were immunized with soluble gp120 or trimeric gp140 proteins in combination with the adjuvant dimethyl dioctadecyl ammonium/trehalose dibehenate (CAF01). Env binding in rabbit immune serum was determined using ELISAs based on gp120-IIIB protein. Neutralizing activity of IgG purified from rabbit immune sera was measured with the pseudovirus-TZMbl assay and a PBMC-based neutralization assay for selected experiments. Results It was initially established that gp140 trimers induce better antibody responses over gp120 monomers and that the adjuvant CAF01 was necessary for such strong responses. Gp140 trimers, based on HIV-1 variants from patients with bNAbs, were able to elicit both gp120IIIB specific IgG and NAbs to Tier 1 viruses of different subtypes. Potency of NAbs closely correlated with titers, and an gp120-binding IgG titer above a threshold of 100,000 was predictive of neutralization capability. Finally, peptide inhibition experiments showed that a large fraction of the neutralizing IgG was directed against the gp120 V3 region. Conclusions Our results indicate that the strategy of reverse immunology based on selected Env sequences is promising when immunogens are delivered as stabilized trimers in CAF01 adjuvant and that the rabbit is a valuable model for HIV vaccine studies.
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Affiliation(s)
- Leo Heyndrickx
- Biomedical Department, Virology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- * E-mail:
| | - Guillaume Stewart-Jones
- Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Marianne Jansson
- Department of Laboratory Medicine, Lund University, Lund, Sweden
| | - Hanneke Schuitemaker
- Department of Experimental Immunology, Academic Medical Center at the University of Amsterdam, Amsterdam, The Netherlands
| | - Emma Bowles
- Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Luigi Buonaguro
- Molecular Biology and Viral Oncogenesis Unit, Istituto Nazionale Tumori, Naples, Italy
| | | | | | - Katleen Vereecken
- Biomedical Department, Virology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Joe Parker
- Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Meghna Ramaswamy
- National Institute for Biological Standards and Control, Hertfordshire, United Kingdom
| | - Priscilla Biswas
- Viral Evolution and Transmission Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
| | - Guido Vanham
- Biomedical Department, Virology Unit, Institute of Tropical Medicine, Antwerp, Belgium
- Biomedical Department, University of Antwerp, Antwerp, Belgium
| | - Gabriella Scarlatti
- Viral Evolution and Transmission Unit, Division of Immunology, Transplantation and Infectious Diseases, San Raffaele Scientific Institute, Milan, Italy
| | - Anders Fomsgaard
- Statens Serum Institut, Copenhagen, Denmark
- Clinical Institute, University of Southern Denmark, Odense, Denmark
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Visciano ML, Tagliamonte M, Stewart-Jones G, Heyndrickx L, Vanham G, Jansson M, Fomsgaard A, Grevstad B, Ramaswamy M, Buonaguro FM, Tornesello ML, Biswas P, Scarlatti G, Buonaguro L. Characterization of humoral responses to soluble trimeric HIV gp140 from a clade A Ugandan field isolate. J Transl Med 2013; 11:165. [PMID: 23835244 PMCID: PMC3729709 DOI: 10.1186/1479-5876-11-165] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 06/20/2013] [Indexed: 11/25/2022] Open
Abstract
Trimeric soluble forms of HIV gp140 envelope glycoproteins represent one of the closest molecular structures compared to native spikes present on intact virus particles. Trimeric soluble gp140 have been generated by several groups and such molecules have been shown to induce antibodies with neutralizing activity against homologous and heterologous viruses. In the present study, we generated a recombinant trimeric soluble gp140, derived from a previously identified Ugandan A-clade HIV field isolate (gp14094UG018). Antibodies elicited in immunized rabbits show a broad binding pattern to HIV envelopes of different clades. An epitope mapping analysis reveals that, on average, the binding is mostly focused on the C1, C2, V3, V5 and C5 regions. Immune sera show neutralization activity to Tier 1 isolates of different clades, demonstrating cross clade neutralizing activity which needs to be further broadened by possible structural modifications of the clade A gp14094UG018. Our results provide a rationale for the design and evaluation of immunogens and the clade A gp14094UG018 shows promising characteristics for potential involvement in an effective HIV vaccine with broad activity.
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Affiliation(s)
- Maria Luisa Visciano
- Molecular Biology and Viral Oncogenesis Unit, Department of Experimental Oncology, Istituto Nazionale per lo Studio e la Cura dei Tumori "Fondazione Pascale" - IRCCS, Naples, Italy
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Influences on trimerization and aggregation of soluble, cleaved HIV-1 SOSIP envelope glycoprotein. J Virol 2013; 87:9873-85. [PMID: 23824824 DOI: 10.1128/jvi.01226-13] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We describe methods to improve the properties of soluble, cleaved gp140 trimers of the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins (Env) for use in structural studies and as immunogens. In the absence of nonionic detergents, gp140 of the KNH1144 genotype, terminating at residue 681 in gp41 (SOSIP.681), has a tendency to form higher-order complexes or aggregates, which is particularly undesirable for structure-based research. We found that this aggregation in the absence of detergent does not involve the V1, V2, or V3 variable regions of gp120. Moreover, we observed that detergent forms micelles around the membrane-proximal external region (MPER) of the SOSIP.681 gp140 trimers, whereas deletion of most of the MPER residues by terminating the gp140 at residue 664 (SOSIP.664) prevented the aggregation that otherwise occurs in SOSIP.681 in the absence of detergent. Although the MPER can contribute to trimer formation, truncation of most of it only modestly reduced trimerization and lacked global adverse effects on antigenicity. Thus, the MPER deletion minimally influenced the kinetics of the binding of soluble CD4 and a CD4-binding site antibody to immobilized trimers, as detected by surface plasmon resonance. Furthermore, the MPER deletion did not alter the overall three-dimensional structure of the trimers, as viewed by negative-stain electron microscopy. Homogeneous and aggregate-free MPER-truncated SOSIP Env trimers are therefore useful for immunogenicity and structural studies.
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Zhang L, Miao L, Gong X, Zhang H, Yang L, Shi Y, Kong W, Jiang C, Shan Y. Multiple antigen peptide mimetics containing gp41 membrane-proximal external region elicit broad neutralizing antibodies against human immunodeficiency virus type 1 in guinea pigs. J Pept Sci 2013; 19:491-8. [DOI: 10.1002/psc.2526] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 05/12/2013] [Accepted: 05/13/2013] [Indexed: 12/12/2022]
Affiliation(s)
- Lishuang Zhang
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Liang Miao
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Xin Gong
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Huayan Zhang
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Lan Yang
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Yuhua Shi
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Wei Kong
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Chunlai Jiang
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
| | - Yaming Shan
- National Engineering Laboratory of AIDS Vaccine, College of Life Science; Jilin University; Changchun China
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Stieh DJ, Phillips JL, Rogers PM, King DF, Cianci GC, Jeffs SA, Gnanakaran S, Shattock RJ. Dynamic electrophoretic fingerprinting of the HIV-1 envelope glycoprotein. Retrovirology 2013; 10:33. [PMID: 23514633 PMCID: PMC3648349 DOI: 10.1186/1742-4690-10-33] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/07/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Interactions between the HIV-1 envelope glycoprotein (Env) and its primary receptor CD4 are influenced by the physiological setting in which these events take place. In this study, we explored the surface chemistry of HIV-1 Env constructs at a range of pH and salinities relevant to mucosal and systemic compartments through electrophoretic mobility (EM) measurements. Sexual transmission events provide a more acidic environment for HIV-1 compared to dissemination and spread of infection occurring in blood or lymph node. We hypothesize functional, trimeric Env behaves differently than monomeric forms. RESULTS The dynamic electrophoretic fingerprint of trimeric gp140 revealed a change in EM from strongly negative to strongly positive as pH increased from that of the lower female genital tract (pHx) to that of the blood (pHy). Similar findings were observed using a trimeric influenza Haemagglutinin (HA) glycoprotein, indicating that this may be a general attribute of trimeric viral envelope glycoproteins. These findings were supported by computationally modeling the surface charge of various gp120 and HA crystal structures. To identify the behavior of the infectious agent and its target cells, EM measurements were made on purified whole HIV-1 virions and primary T-lymphocytes. Viral particles had a largely negative surface charge, and lacked the regions of positivity near neutral pH that were observed with trimeric Env. T cells changed their surface chemistry as a function of activation state, becoming more negative over a wider range of pH after activation. Soluble recombinant CD4 (sCD4) was found to be positively charged under a wide range of conditions. Binding studies between sCD4 and gp140 show that the affinity of CD4-gp140 interactions depends on pH. CONCLUSIONS Taken together, these findings allow a more complete model of the electrochemical forces involved in HIV-1 Env functionality. These results indicate that the influence of the localized environment on the interactions of HIV with target cells are more pronounced than previously appreciated. There is differential chemistry of trimeric, but not monomeric, Env under conditions which mimic the mucosa compared to those found systemically. This should be taken into consideration during design of immunogens which targets virus at mucosal portals of entry.
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Affiliation(s)
- Daniel J Stieh
- Center for Infection, Department of Cellular and Molecular Medicine, St. George's University of London, London SW17 0RE, UK
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Leaman DP, Zwick MB. Increased functional stability and homogeneity of viral envelope spikes through directed evolution. PLoS Pathog 2013; 9:e1003184. [PMID: 23468626 PMCID: PMC3585149 DOI: 10.1371/journal.ppat.1003184] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 12/21/2012] [Indexed: 11/19/2022] Open
Abstract
The functional HIV-1 envelope glycoprotein (Env) trimer, the target of anti-HIV-1 neutralizing antibodies (Abs), is innately labile and coexists with non-native forms of Env. This lability and heterogeneity in Env has been associated with its tendency to elicit non-neutralizing Abs. Here, we use directed evolution to overcome instability and heterogeneity of a primary Env spike. HIV-1 virions were subjected to iterative cycles of destabilization followed by replication to select for Envs with enhanced stability. Two separate pools of stable Env variants with distinct sequence changes were selected using this method. Clones isolated from these viral pools could withstand heat, denaturants and other destabilizing conditions. Seven mutations in Env were associated with increased trimer stability, primarily in the heptad repeat regions of gp41, but also in V1 of gp120. Combining the seven mutations generated a variant Env with superior homogeneity and stability. This variant spike moreover showed resistance to proteolysis and to dissociation by detergent. Heterogeneity within the functional population of hyper-stable Envs was also reduced, as evidenced by a relative decrease in a proportion of virus that is resistant to the neutralizing Ab, PG9. The latter result may reflect a change in glycans on the stabilized Envs. The stabilizing mutations also increased the proportion of secreted gp140 existing in a trimeric conformation. Finally, several Env-stabilizing substitutions could stabilize Env spikes from HIV-1 clades A, B and C. Spike stabilizing mutations may be useful in the development of Env immunogens that stably retain native, trimeric structure. A vaccine is needed to prevent HIV/AIDS but eliciting potent neutralizing antibodies (Abs) against primary isolates has been a major stumbling block. The target of HIV-1 neutralizing antibodies is the native envelope glycoprotein (Env) trimer that is displayed on the surface of the virus. Virion associated Env typically elicits antibodies that cannot neutralize primary viruses. However, because native Env trimers can dissociate and coexist with non-fusogenic forms of Env interpreting these results are difficult. Here, we used directed evolution to select for virions that display native Env with increased stability and homogeneity. HIV-1 virions were subjected to increasingly harsh treatments that destabilize Env trimers, and the variants that survived each treatment were expanded. We could identify seven different mutations in Env that increased its stability of function in the face of multiple destabilizing treatments. When these mutations were combined, the resulting mutant Env trimers were far more stable than the original Env protein. Incorporating trimer-stabilizing mutations into Env-based immunogens should facilitate vaccine research by mitigating the confounding effects of non-native byproducts of Env decay. A similar approach may be used on other pathogens with potential vaccine targets that are difficult to isolate and maintain in a native form.
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Affiliation(s)
- Daniel P. Leaman
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Michael B. Zwick
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Antigenicity and immunogenicity of transmitted/founder, consensus, and chronic envelope glycoproteins of human immunodeficiency virus type 1. J Virol 2013; 87:4185-201. [PMID: 23365441 DOI: 10.1128/jvi.02297-12] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) vaccine development requires selection of appropriate envelope (Env) immunogens. Twenty HIV-1 Env glycoproteins were examined for their ability to bind human anti-HIV-1 monoclonal antibodies (MAbs) and then used as immunogens in guinea pigs to identify promising immunogens. These included five Envs derived from chronically infected individuals, each representing one of five common clades and eight consensus Envs based on these five clades, as well as the consensus of the entire HIV-1 M group, and seven transmitted/founder (T/F) Envs from clades B and C. Sera from immunized guinea pigs were tested for neutralizing activity using 36 HIV-1 Env-pseudotyped viruses. All Envs bound to CD4 binding site, membrane-proximal, and V1/V2 MAbs with similar apparent affinities, although the T/F Envs bound with higher affinity to the MAb 17b, a CCR5 coreceptor binding site antibody. However, the various Envs differed in their ability to induce neutralizing antibodies. Consensus Envs elicited the most potent responses, but neutralized only a subset of viruses, including mostly easy-to-neutralize tier 1 and some more-difficult-to-neutralize tier 2 viruses. T/F Envs elicited fewer potent neutralizing antibodies but exhibited greater breadth than chronic or consensus Envs. Finally, chronic Envs elicited the lowest level and most limited breadth of neutralizing antibodies overall. Thus, each group of Env immunogens elicited a different antibody response profile. The complementary benefits of consensus and T/F Env immunogens raise the possibility that vaccines utilizing a combination of consensus and T/F Envs may be able to induce neutralizing responses with greater breadth and potency than single Env immunogens.
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63
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Chen W, Ying T, Dimitrov DS. Antibody-based candidate therapeutics against HIV-1: implications for virus eradication and vaccine design. Expert Opin Biol Ther 2013; 13:657-71. [PMID: 23293858 DOI: 10.1517/14712598.2013.761969] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The currently available anti-HIV-1 drugs can control the infection but do not eradicate the virus. Their long-term use can lead to side effects and resistance to therapy. Therefore, eradication of the virus has been a major goal of research. Biological therapeutics including broadly neutralizing monoclonal antibodies (bnAbs) are promising tools to reach this goal. They could also help design novel vaccine immunogens potentially capable of eliciting bnAbs targeting the HIV-1 envelope glycoproteins (Envs). AREAS COVERED We review HIV-1 bnAbs and their potential as candidate prophylactics and therapeutics used individually, in combination, or as bispecific fusion proteins. We also discuss their potential use in the 'activation-elimination' approach for HIV-1 eradication in infected patients receiving antiretroviral treatment as well as current vaccine design efforts based on understanding of interactions of candidate vaccine immunogens with matured bnAbs and their putative germline predecessors, and related antibody maturation pathways. EXPERT OPINION Exploration of HIV-1 bnAbs has provided and will continue to provide useful knowledge that helps develop novel types of biotherapeutics and vaccines. It is possible that bnAb-based candidate therapeutics could help eradicate HIV-1. Development of vaccine immunogens capable of eliciting potent bnAbs in humans remains a fundamental challenge.
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Affiliation(s)
- Weizao Chen
- National Cancer Institute, National Institutes of Health, Frederick National Laboratory for Cancer Research, Protein Interactions Group, Miller Drive, Building 469, Room 144, Frederick, MD 21702, USA.
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Mata-Fink J, Kriegsman B, Yu HX, Zhu H, Hanson MC, Irvine DJ, Wittrup KD. Rapid conformational epitope mapping of anti-gp120 antibodies with a designed mutant panel displayed on yeast. J Mol Biol 2012; 425:444-56. [PMID: 23159556 PMCID: PMC3785227 DOI: 10.1016/j.jmb.2012.11.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Revised: 11/06/2012] [Accepted: 11/07/2012] [Indexed: 11/16/2022]
Abstract
gp120 is a substrate for protein engineering both for human immunodeficiency virus (HIV) immunogen design and as a bait for isolating anti-HIV antibodies from patient samples. In this work, we describe the display of a stripped core gp120 on the yeast cell surface. Validation against a panel of neutralizing antibodies confirms that yeast-displayed gp120 presents the CD4 binding site in the correct conformation. We map the epitope of the broadly neutralizing anti-gp120 antibody VRC01 using both a random mutagenesis library and a defined mutant panel and find that the resultant epitope maps are consistent with one another and with the crystallographically identified contact residues. Mapping the VRC01-competitive antibodies b12 and b13 reveals energetic differences in their epitopes that are not obvious from existing crystal structures. These data suggest mutation sets that abrogate binding to broadly neutralizing antibodies with greater specificity than the canonical mutation D368R, useful in rapidly assessing the nature of a vaccine response.
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Affiliation(s)
- Jordi Mata-Fink
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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65
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Optimization and proficiency testing of a pseudovirus-based assay for detection of HIV-1 neutralizing antibody in China. J Virol Methods 2012; 185:267-75. [DOI: 10.1016/j.jviromet.2012.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 06/28/2012] [Accepted: 07/04/2012] [Indexed: 11/23/2022]
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66
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Zhang Z, Zhang X, Newman K, Liu X. MicroRNA Regulation of Oncolytic Adenovirus 6 for Selective Treatment of Castration-Resistant Prostate Cancer. Mol Cancer Ther 2012; 11:2410-8. [DOI: 10.1158/1535-7163.mct-12-0157] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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67
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Kramski M, Center RJ, Wheatley AK, Jacobson JC, Alexander MR, Rawlin G, Purcell DFJ. Hyperimmune bovine colostrum as a low-cost, large-scale source of antibodies with broad neutralizing activity for HIV-1 envelope with potential use in microbicides. Antimicrob Agents Chemother 2012; 56:4310-9. [PMID: 22664963 PMCID: PMC3421555 DOI: 10.1128/aac.00453-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 05/23/2012] [Indexed: 11/20/2022] Open
Abstract
Bovine colostrum (first milk) contains very high concentrations of IgG, and on average 1 kg (500 g/liter) of IgG can be harvested from each immunized cow immediately after calving. We used a modified vaccination strategy together with established production systems from the dairy food industry for the large-scale manufacture of broadly neutralizing HIV-1 IgG. This approach provides a low-cost mucosal HIV preventive agent potentially suitable for a topical microbicide. Four cows were vaccinated pre- and/or postconception with recombinant HIV-1 gp140 envelope (Env) oligomers of clade B or A, B, and C. Colostrum and purified colostrum IgG were assessed for cross-clade binding and neutralization against a panel of 27 Env-pseudotyped reporter viruses. Vaccination elicited high anti-gp140 IgG titers in serum and colostrum with reciprocal endpoint titers of up to 1 × 10(5). While nonimmune colostrum showed some intrinsic neutralizing activity, colostrum from 2 cows receiving a longer-duration vaccination regimen demonstrated broad HIV-1-neutralizing activity. Colostrum-purified polyclonal IgG retained gp140 reactivity and neutralization activity and blocked the binding of the b12 monoclonal antibody to gp140, showing specificity for the CD4 binding site. Colostrum-derived anti-HIV antibodies offer a cost-effective option for preparing the substantial quantities of broadly neutralizing antibodies that would be needed in a low-cost topical combination HIV-1 microbicide.
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Affiliation(s)
- Marit Kramski
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Rob J. Center
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Adam K. Wheatley
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Jonathan C. Jacobson
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Marina R. Alexander
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
| | - Grant Rawlin
- Immuron Ltd., North Melbourne, Victoria, Australia
| | - Damian F. J. Purcell
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, Australia
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HIV-1 envelope trimer elicits more potent neutralizing antibody responses than monomeric gp120. Proc Natl Acad Sci U S A 2012; 109:12111-6. [PMID: 22773820 DOI: 10.1073/pnas.1204533109] [Citation(s) in RCA: 142] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
HIV-1 envelope glycoprotein is the primary target for HIV-1-specific antibodies. The native HIV-1 envelope spike on the virion surface is a trimer, but trimeric gp140 and monomeric gp120 currently are believed to induce comparable immune responses. Indeed, most studies on the immunogenicity of HIV-1 envelope oligomers have revealed only marginal improvement over monomers. We report here that suitably prepared envelope trimers have nearly all the antigenic properties expected for native viral spikes. These stable, rigorously homogenous trimers have antigenic properties markedly different from those of monomeric gp120s derived from the same sequences, and they induce potent neutralizing antibody responses for a cross-clade set of tier 1 and tier 2 viruses with titers substantially higher than those elicited by the corresponding gp120 monomers. These results, which demonstrate that there are relevant immunologic differences between monomers and high-quality envelope trimers, have important implications for HIV-1 vaccine development.
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Pissani F, Malherbe DC, Robins H, DeFilippis VR, Park B, Sellhorn G, Stamatatos L, Overbaugh J, Haigwood NL. Motif-optimized subtype A HIV envelope-based DNA vaccines rapidly elicit neutralizing antibodies when delivered sequentially. Vaccine 2012; 30:5519-26. [PMID: 22749601 DOI: 10.1016/j.vaccine.2012.06.042] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 06/09/2012] [Accepted: 06/14/2012] [Indexed: 12/14/2022]
Abstract
HIV-1 infection results in the development of a diverging quasispecies unique to each infected individual. Envelope (Env)-specific neutralizing antibodies (NAbs) typically develop over months to years after infection and initially are limited to the infecting virus. In some subjects, antibody responses develop that neutralize heterologous isolates (HNAbs), a phenomenon termed broadening of the NAb response. Studies of co-crystalized antibodies and proteins have facilitated the identification of some targets of broadly neutralizing monoclonal antibodies (NmAbs) capable of neutralizing many or most heterologous viruses; however, the ontogeny of these antibodies in vivo remains elusive. We hypothesize that Env protein escape variants stimulate broad NAb development in vivo and could generate such NAbs when used as immunogens. Here we test this hypothesis in rabbits using HIV Env vaccines featuring: (1) use of individual quasispecies env variants derived from an HIV-1 subtype A-infected subject exhibiting high levels of NAbs within the first year of infection that increased and broadened with time; (2) motif optimization of envs to enhance in vivo expression of DNA formulated as vaccines; and (3) a combined DNA plus protein boosting regimen. Vaccines consisted of multiple env variants delivered sequentially and a simpler regimen that utilized only the least and most divergent clones. The simpler regimen was as effective as the more complex approach in generating modest HNAbs and was more efficient when modified, motif-optimized DNA was used in combination with trimeric gp140 protein. This is a rationally designed strategy that facilitates future vaccine design by addressing the difficult problem of generating HNAbs to HIV by empirically testing the immunogenicity of naturally occurring quasispecies env variants.
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Affiliation(s)
- Franco Pissani
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97217, USA
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Eliciting broad neutralizing antibody to HIV-1: envelopes of different lentivirus cross immunization by prime-boost vaccination. Vaccine 2012; 30:5316-23. [PMID: 22749599 DOI: 10.1016/j.vaccine.2012.06.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/18/2012] [Accepted: 06/16/2012] [Indexed: 12/24/2022]
Abstract
The greatest challenge of HIV vaccine development lies in the diversity of circulating HIV-1 strains. For an effective vaccine, neutralizing antibodies are assumed to be of crucial importance, but previous attempts results only very limited breadth and potency of Nab titer. While the amino acid sequences of lentivirus envelope have many differences, those envelope proteins share almost same structural conformations. If the envelopes of different lentivirus were used immune animals, the response to the conserved sites will be strengthened while the un-conserved sites will not be. In this study, compared to only protein immunization regimen, HIV-1 CN54 gp140 DNA prime and protein boost strategy generated Nab titer increased significantly. So, the prime-boost strategy and HIV-1 CN54 gp140 protein were employed to different lentivirus cross immunization schedule. The results indicated that, the different lentivirus and HIV-1 cross immune by prime-boost strategy elicited breath and potency neutralization antibody to tier 1, tier 2, and tier 3 viruses with 14 tested viruses. To tested tier 2 and tier 3 viruses, in SIV and HIV-1 cross immunization group, the neutralization breadth of ID50 is 91.7% and the breadth of ID70 is 50%; in HIV-1, FIV and SIV cross immunization group, the breadth of ID50 is 83.3% and the breadth of ID70 is 58.3%, while in only HIV-1 vaccinated group, the breadth of ID50 is 75% and the breadth of ID70 is only 25%. These data demonstrate that HIV-1 and different lentivirus especially with SIV cross immunization by prime-boost strategy elicit broad neutralizing antibodies much better than only HIV-1 immunization.
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71
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Vaccine protection against acquisition of neutralization-resistant SIV challenges in rhesus monkeys. Nature 2012; 482:89-93. [PMID: 22217938 PMCID: PMC3271177 DOI: 10.1038/nature10766] [Citation(s) in RCA: 396] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 12/07/2011] [Indexed: 01/10/2023]
Abstract
Preclinical studies of HIV-1 vaccine candidates have typically shown post-infection virologic control, but protection against acquisition of infection has previously only been reported against neutralization-sensitive virus challenges1–3. Here we demonstrate vaccine protection against acquisition of fully heterologous, neutralization-resistant virus challenges in rhesus monkeys. Adenovirus/poxvirus and adenovirus/adenovirus vector-based vaccines expressing SIVsmE543 Gag, Pol, and Env antigens resulted in a ≥80% reduction in the per-exposure probability of infection4,5 against repetitive, intrarectal SIVmac251 challenges in rhesus monkeys. Protection against acquisition of infection exhibited distinct immunologic correlates as compared with post-infection virologic control and required the inclusion of Env in the vaccine regimen. These data demonstrate the first proof-of-concept that optimized HIV-1 vaccine candidates can block acquisition of stringent, heterologous, neutralization-resistant virus challenges in rhesus monkeys.
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Feng Y, McKee K, Tran K, O'Dell S, Schmidt SD, Phogat A, Forsell MN, Karlsson Hedestam GB, Mascola JR, Wyatt RT. Biochemically defined HIV-1 envelope glycoprotein variant immunogens display differential binding and neutralizing specificities to the CD4-binding site. J Biol Chem 2011; 287:5673-86. [PMID: 22167180 DOI: 10.1074/jbc.m111.317776] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HIV-1 gp120 binds the primary receptor CD4. Recently, a plethora of broadly neutralizing antibodies to the gp120 CD4-binding site (CD4bs) validated this region as a target for immunogen design. Here, we asked if modified HIV-1 envelope glycoproteins (Env) designed to increase CD4 recognition might improve recognition by CD4bs neutralizing antibodies and more efficiently elicit such reactivities. We also asked if CD4bs stabilization, coupled with altering the Env format (monomer to trimer or cross-clade), might better elicit neutralizing antibodies by focusing the immune response on the functionally conserved CD4bs. We produced monomeric and trimeric Envs stabilized by mutations within the gp120 CD4bs cavity (pocket-filling; PF2) or by appending heterologous trimerization motifs to soluble Env ectodomains (gp120/gp140). Recombinant glycoproteins were purified to relative homogeneity, and ligand binding properties were analyzed by ELISA, surface plasmon resonance, and isothermal titration microcalorimetry. In some formats, the PF2 substitutions increased CD4 affinity, and importantly, PF2-containing proteins were better recognized by the broadly neutralizing CD4bs mAbs, VRC01 and VRC-PG04. Based on this analysis, we immunized selected Env variants into rabbits using heterologous or homologous regimens. Analysis of the sera revealed that homologous inoculation of the PF2-containing, variable region-deleted YU2 gp120 trimers (ΔV123/PF2-GCN4) more rapidly elicited CD4bs-directed neutralizing antibodies compared with other regimens, whereas homologous trimers elicited increased neutralization potency, mapping predominantly to the gp120 third major variable region (V3). These results suggest that some engineered Env proteins may more efficiently direct responses toward the conserved CD4bs and be valuable to elicit antibodies of greater neutralizing capacity.
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Affiliation(s)
- Yu Feng
- IAVI Neutralizing Antibody Center, Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California 92037, USA
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Engineering, expression, purification, and characterization of stable clade A/B recombinant soluble heterotrimeric gp140 proteins. J Virol 2011; 86:128-42. [PMID: 22031951 DOI: 10.1128/jvi.06363-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The envelope glycoprotein (Env) of human immunodeficiency virus type 1 (HIV-1) is composed of two noncovalently associated subunits: an extracellular subunit (gp120) and a transmembrane subunit (gp41). The functional unit of Env on the surface of infectious virions is a trimer of gp120/gp41 heterodimers. Env is the target of anti-HIV neutralizing antibodies. A considerable effort has been invested in the engineering of recombinant soluble forms of the virion-associated Env trimer as vaccine candidates to elicit anti-HIV neutralizing antibody responses. These soluble constructs contain three gp120 subunits and the extracellular segments of the corresponding gp41 subunits. The individual gp120/gp41 protomers on these soluble trimers are identical in amino acid sequence (homotrimers). Here, we engineered novel soluble trimeric gp140 proteins that are formed by the association of gp140 protomers that differ in amino acid sequence and glycosylation patterns (heterotrimers). Specifically, we engineered soluble heterotrimeric proteins composed of clade A and clade B Env protomers. The clade A gp140 protomers were derived from viruses isolated during acute infection (Q168a2, Q259d2.17, and Q461e2), whereas the clade B gp140 protomers were derived from a virus isolated during chronic infection (SF162). The amino acid sequence divergence between the clade A and the clade B Envs is approximately 24%. Neutralization epitopes in the CD4 binding sites and coreceptor binding sites, as well as the membrane-proximal external region (MPER), were differentially expressed on the heterotrimeric and homotrimeric proteins. The heterotrimeric gp140s elicited broader anti-tier 1 isolate neutralizing antibody responses than did the homotrimeric gp140s.
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Cross-clade HIV-1 neutralizing antibodies induced with V3-scaffold protein immunogens following priming with gp120 DNA. J Virol 2011; 85:9887-98. [PMID: 21795338 DOI: 10.1128/jvi.05086-11] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The V3 epitope is a known target for HIV-1 neutralizing antibodies (NAbs), and V3-scaffold fusion proteins used as boosting immunogens after gp120 DNA priming were previously shown to induce NAbs in rabbits. Here, we evaluated whether the breadth and potency of the NAb response could be improved when boosted with rationally designed V3-scaffold immunogens. Rabbits were primed with codon-optimized clade C gp120 DNA and boosted with one of five V3-cholera toxin B fusion proteins (V3-CTBs) or with double combinations of these. The inserts in these immunogens were designed to display V3 epitopes shared by the majority of global HIV-1 isolates. Double combinations of V3-CTB immunogens generally induced more broad and potent NAbs than did boosts with single V3-CTB immunogens, with the most potent and broad NAbs elicited with the V3-CTB carrying the consensus V3 of clade C (V3(C)-CTB), or with double combinations of V3-CTB immunogens that included V3(C)-CTB. Neutralization of tier 1 and 2 pseudoviruses from clades AG, B, and C and of peripheral blood mononuclear cell (PBMC)-grown primary viruses from clades A, AG, and B was achieved, demonstrating that priming with gp120 DNA followed by boosts with V3-scaffold immunogens effectively elicits cross-clade NAbs. Focusing on the V3 region is a first step in designing a vaccine targeting protective epitopes, a strategy with potential advantages over the use of Env, a molecule that evolved to protect the virus by poorly inducing NAbs and by shielding the epitopes that are most critical for infectivity.
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75
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Of mice and not humans: how reliable are animal models for evaluation of herpes CD8(+)-T cell-epitopes-based immunotherapeutic vaccine candidates? Vaccine 2011; 29:5824-36. [PMID: 21718746 DOI: 10.1016/j.vaccine.2011.06.083] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 06/09/2011] [Accepted: 06/14/2011] [Indexed: 11/23/2022]
Abstract
Herpes simplex virus type 1 and type 2 (HSV-1 and HSV-2)-specific CD8(+) T cells that reside in sensory ganglia, appear to control recurrent herpetic disease by aborting or reducing spontaneous and sporadic reactivations of latent virus. A reliable animal model is the ultimate key factor to test the efficacy of therapeutic vaccines that boost the level and the quality of sensory ganglia-resident CD8(+) T cells against spontaneous herpes reactivation from sensory neurons, yet its relevance has been often overlooked. Herpes vaccinologists are hesitant about using mouse as a model in pre-clinical development of therapeutic vaccines because they do not adequately mimic spontaneous viral shedding or recurrent symptomatic diseases, as occurs in human. Alternatives to mouse models are rabbits and guinea pigs in which reactivation arise spontaneously with clinical herpetic features relevant to human disease. However, while rabbits and guinea pigs develop spontaneous HSV reactivation and recurrent ocular and genital disease none of them can mount CD8(+) T cell responses specific to Human Leukocyte Antigen- (HLA-)restricted epitopes. In this review, we discuss the advantages and limitations of these animal models and describe a novel "humanized" HLA transgenic rabbit, which shows spontaneous HSV-1 reactivation, recurrent ocular disease and mounts CD8(+) T cell responses to HLA-restricted epitopes. Adequate investments are needed to develop reliable preclinical animal models, such as HLA class I and class II double transgenic rabbits and guinea pigs to balance the ethical and financial concerns associated with the rising number of unsuccessful clinical trials for therapeutic vaccine formulations tested in unreliable mouse models.
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76
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Recombinant trimeric HA protein immunogenicity of H5N1 avian influenza viruses and their combined use with inactivated or adenovirus vaccines. PLoS One 2011; 6:e20052. [PMID: 21655326 PMCID: PMC3104987 DOI: 10.1371/journal.pone.0020052] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 04/11/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The highly pathogenic avian influenza (HPAI) H5N1 virus continues to cause disease in poultry and humans. The hemagglutinin (HA) envelope protein is the primary target for subunit vaccine development. METHODOLOGY/PRINCIPAL FINDINGS We used baculovirus-insect cell expression to obtain trimeric recombinant HA (rHA) proteins from two HPAI H5N1 viruses. We investigated trimeric rHA protein immunogenicity in mice via immunizations, and found that the highest levels of neutralizing antibodies resulted from coupling with a PELC/CpG adjuvant. We also found that the combined use of trimeric rHA proteins with (a) an inactivated H5N1 vaccine virus, or (b) a recombinant adenovirus encoding full-length HA sequences for prime-boost immunization, further improved antibody responses against homologous and heterologous H5N1 virus strains. Data from cross-clade prime-boost immunization regimens indicate that sequential immunization with different clade HA antigens increased antibody responses in terms of total IgG level and neutralizing antibody titers. CONCLUSION/SIGNIFICANCE Our findings suggest that the use of trimeric rHA in prime-boost vaccine regimens represents an alternative strategy for recombinant H5N1 vaccine development.
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Charles-Niño C, Pedroza-Roldan C, Viveros M, Gevorkian G, Manoutcharian K. Variable epitope libraries: new vaccine immunogens capable of inducing broad human immunodeficiency virus type 1-neutralizing antibody response. Vaccine 2011; 29:5313-21. [PMID: 21600948 DOI: 10.1016/j.vaccine.2011.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/03/2011] [Accepted: 05/04/2011] [Indexed: 11/25/2022]
Abstract
The extreme antigenic variability of human immunodeficiency virus (HIV) leads to immune escape of the virus, representing a major challenge in the design of effective vaccine. We have developed a novel concept for immunogen construction based on introduction of massive mutations within the epitopes targeting antigenically variable pathogens and diseases. Previously, we showed that these immunogens carrying large combinatorial libraries of mutated epitope variants, termed as variable epitope libraries (VELs), induce potent, broad and long lasting CD8+IFN-γ+ T-cell response. Moreover, we demonstrated that these T cells recognize more than 50% of heavily mutated variants (5 out of 10 amino acid positions were mutated in each epitope variant) of HIV-1 gp120 V3 loop-derived cytotoxic T lymphocyte epitope (RGPGRAFVTI) in mice. The constructed VELs had complexities of 10000 and 12500 individual members, generated as plasmid DNA or as M13 phage display combinatorial libraries, respectively, and with structural composition RGPGXAXXXX or XGXGXAXVXI, where X is any of 20 natural amino acids. Here, we demonstrated that sera from mice immunized with these VELs are capable of neutralizing 5 out of 10 viral isolates from Tier 2 reference panel of subtype B envelope clones, including HIV-1 isolates which are known to be resistant to neutralization by several potent monoclonal antibodies, described previously. These data indicate the feasibility of the application of immunogens based on VEL concept as an alternative approach for the development of molecular vaccines against antigenically variable pathogens.
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Affiliation(s)
- Claudia Charles-Niño
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70228, Cuidad Universitaria, México, Distrito Federal 04510, Mexico
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Binding interactions between soluble HIV envelope glycoproteins and quaternary-structure-specific monoclonal antibodies PG9 and PG16. J Virol 2011; 85:7095-107. [PMID: 21543501 DOI: 10.1128/jvi.00411-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PG9 and PG16 are antibodies isolated from a subject infected with HIV-1 and display broad anti-HIV neutralizing activities. They recognize overlapping epitopes, which are preferentially expressed on the membrane-anchored trimeric form of the HIV envelope glycoprotein (Env). PG9 and PG16 were reported not to bind to soluble mimetics of Env. The engineering of soluble Env proteins on which the PG9 and PG16 epitopes are optimally exposed will support efforts to elicit broad anti-HIV neutralizing antibodies by immunization. Here, we identified several soluble gp140 Env proteins that are recognized by PG9 and PG16, and we investigated the molecular details of those binding interactions. The IgG versions of PG9 and PG16 recognize the soluble trimeric gp140 form less efficiently than the corresponding monomeric gp140 form. In contrast, the Fab versions of PG9 and PG16 recognized the monomeric and trimeric gp140 forms with identical binding kinetics and with binding affinities similar to the high binding affinity of the anti-V3 antibody 447D to its epitope. Our data also indicate that, depending on the Env backbone, the interactions of PG9 and PG16 with gp140 may be facilitated by the presence of the gp41 ectodomain and are independent of the proper enzymatic cleavage of gp140 into gp120 and gp41. The identification of soluble Env proteins that express the PG9 and PG16 epitopes and the detailed characterization of the molecular interactions between these two antibodies and their ligands provide important and novel information that will assist in improving the engineering of future Env immunogens.
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Modulation of plasmid DNA vaccine antigen clearance by caspase 12 RNA interference potentiates vaccination. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2011; 18:533-8. [PMID: 21325489 DOI: 10.1128/cvi.00390-10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The magnitude of the immune responses elicited by plasmid DNA vaccines might be limited, in part, by the duration of vaccine antigen expression in vivo. To explore strategies for improving plasmid DNA vaccine efficacy, we studied the apoptotic process in myocytes of mice vaccinated intramuscularly. We found that after vaccination, the proapoptotic protein caspase 12 (Casp12) was upregulated in myocytes coincident with the loss of vaccine antigen expression. To harness this observation to improve plasmid DNA vaccine efficacy, we used RNA interference technology, coadministering plasmid DNA expressing a short hairpin RNA (shRNA) of Casp12 with plasmid DNA vaccine constructs. This treatment with shRNA Casp12, administered twice within the first 10 days following vaccine administration, increased antigen expression 7-fold, the antigen-specific CD8(+) T cell immune response 6-fold, and antigen-specific antibody production 5-fold. This study demonstrates the critical role for Casp12 in plasmid DNA vaccine-induced immune responses and shows that increased antigen expression mediated by down-modulation of Casp12 can be used to potentiate vaccine efficacy.
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Abstract
A major hurdle in the development of a global HIV-1 vaccine is viral diversity. For close to three decades, HIV vaccine development has focused on either the induction of T cell immune responses or antibody responses, and only rarely on both components. After the failure of the STEP trial, the scientific community concluded that a T cell-based vaccine would likely not be protective if the T cell immune responses were elicited against only a few dominant epitopes. Similarly, for vaccines focusing on antibody responses, one of the main criticisms after VaxGen's failed Phase III trials was on the limited antigen breadth included in the two formulations used. The successes of polyvalent vaccine approaches against other antigenically variable pathogens encourage implementation of the same approach for the design of HIV-1 vaccines. A review of the existing HIV-1 vaccination approaches based on the polyvalent principle is included here to provide a historical perspective for the current effort of developing a polyvalent HIV-1 vaccine. Results summarized in this review provide a clear indication that the polyvalent approach is a viable one for the future development of an effective HIV vaccine.
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Affiliation(s)
- Shan Lu
- Laboratory of Nucleic Acid Vaccines, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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Smith DH, Winters-Digiacinto P, Mitiku M, O'Rourke S, Sinangil F, Wrin T, Montefiori DC, Berman PW. Comparative immunogenicity of HIV-1 clade C envelope proteins for prime/boost studies. PLoS One 2010; 5:e12076. [PMID: 20711452 PMCID: PMC2920315 DOI: 10.1371/journal.pone.0012076] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 07/16/2010] [Indexed: 11/18/2022] Open
Abstract
Background Previous clinical efficacy trials failed to support the continued development of recombinant gp120 (rgp120) as a candidate HIV vaccine. However, the recent RV144 HIV vaccine trial in Thailand showed that a prime/boost immunization strategy involving priming with canarypox vCP1521 followed by boosting with rgp120 could provide significant, although modest, protection from HIV infection. Based on these results, there is renewed interest in the development of rgp120 based antigens for follow up vaccine trials, where this immunization approach can be applied to other cohorts at high risk for HIV infection. Of particular interest are cohorts in Africa, India, and China that are infected with clade C viruses. Methodology/Principal Findings A panel of 10 clade C rgp120 envelope proteins was expressed in 293 cells, purified by immunoaffinity chromatography, and used to immunize guinea pigs. The resulting sera were collected and analyzed in checkerboard experiments for rgp120 binding, V3 peptide binding, and CD4 blocking activity. Virus neutralization studies were carried out with two different assays and two different panels of clade C viruses. A high degree of cross reactivity against clade C and clade B viruses and viral proteins was observed. Most, but not all of the immunogens tested elicited antibodies that neutralized tier 1 clade B viruses, and some sera neutralized multiple clade C viruses. Immunization with rgp120 from the CN97001 strain of HIV appeared to elicit higher cross neutralizing antibody titers than the other antigens tested. Conclusions/Significance While all of the clade C antigens tested were immunogenic, some were more effective than others in eliciting virus neutralizing antibodies. Neutralization titers did not correlate with rgp120 binding, V3 peptide binding, or CD4 blocking activity. CN97001 rgp120 elicited the highest level of neutralizing antibodies, and should be considered for further HIV vaccine development studies.
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Affiliation(s)
| | | | - Misrach Mitiku
- VaxGen, Inc., Brisbane, California, United States of America
| | - Sara O'Rourke
- Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Faruk Sinangil
- VaxGen, Inc., Brisbane, California, United States of America
- Global Solutions For Infectious Diseases, South San Francisco, California, United States of America
| | - Terri Wrin
- Monogram Biosciences, South San Francisco, California, United States of America
| | - David C. Montefiori
- Duke University Medical School, Durham, North Carolina, United States of America
| | - Phillip W. Berman
- VaxGen, Inc., Brisbane, California, United States of America
- Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
- * E-mail:
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