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Bale S, Yang L, Alirezaei M, Wilson R, Ota T, Doyle ED, Cottrell C, Guenaga J, Tran K, Li W, Stamatatos L, Nemazee D, Ward AB, Wyatt RT. Fusion of the molecular adjuvant C3d to cleavage-independent native-like HIV-1 Env trimers improves the elicited antibody response. Front Immunol 2023; 14:1180959. [PMID: 37283743 PMCID: PMC10239957 DOI: 10.3389/fimmu.2023.1180959] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 04/27/2023] [Indexed: 06/08/2023] Open
Abstract
An effective HIV vaccine likely requires the elicitation of neutralizing antibodies (NAbs) against multiple HIV-1 clades. The recently developed cleavage-independent native flexibly linked (NFL) envelope (Env) trimers exhibit well-ordered conformation and elicit autologous tier 2 NAbs in multiple animal models. Here, we investigated whether the fusion of molecular adjuvant C3d to the Env trimers can improve B- cell germinal center (GC) formation and antibody responses. To generate Env-C3d trimers, we performed a glycine-serine- based (G4S) flexible peptide linker screening and identified a linker range that allowed native folding. A 30-60- amino- acid- long linker facilitates Env-to-C3d association and achieves the secretion of well-ordered trimers and the structural integrity and functional integrity of Env and C3d. The fusion of C3d did not dramatically affect the antigenicity of the Env trimers and enhanced the ability of the Env trimers to engage and activate B cells in vitro. In mice, the fusion of C3d enhanced germinal center formation, the magnitude of Env-specific binding antibodies, and the avidity of the antibodies in the presence of an adjuvant. The Sigma Adjuvant System (SAS) did not affect the trimer integrity in vitro but contributed to altered immunogenicity in vivo, resulting in increased tier 1 neutralization, likely by increased exposure of variable region 3 (V3). Taken together, the results indicate that the fusion of the molecular adjuvant, C3d, to the Env trimers improves antibody responses and could be useful for Env-based vaccines against HIV.
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Affiliation(s)
- Shridhar Bale
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Lifei Yang
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Mehrdad Alirezaei
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Richard Wilson
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Takayuki Ota
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Esmeralda D. Doyle
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Christopher A. Cottrell
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Javier Guenaga
- International AIDS Vaccine Initiative, Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, United States
| | - Karen Tran
- International AIDS Vaccine Initiative, Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, United States
| | - Wenjuan Li
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Leonidas Stamatatos
- Vaccines and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, United States
- Department of Global Health, University of Washington, Seattle, WA, United States
| | - David Nemazee
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
| | - Andrew B. Ward
- International AIDS Vaccine Initiative, Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, United States
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, United States
- Consortium for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA, United States
| | - Richard T. Wyatt
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA, United States
- International AIDS Vaccine Initiative, Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA, United States
- Consortium for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA, United States
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2
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King HAD, Gonelli CA, Tullett KM, Lahoud MH, Purcell DFJ, Drummer HE, Poumbourios P, Center RJ. Conjugation of an scFab domain to the oligomeric HIV envelope protein for use in immune targeting. PLoS One 2019; 14:e0220986. [PMID: 31430333 PMCID: PMC6701830 DOI: 10.1371/journal.pone.0220986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 07/28/2019] [Indexed: 11/19/2022] Open
Abstract
A promising strategy for the enhancement of vaccine-mediated immune responses is by directly targeting protein antigens to immune cells. Targeting of antigens to the dendritic cell (DC) molecule Clec9A has been shown to enhance antibody affinity and titers for model antigens, and influenza and enterovirus antigens, and may be advantageous for immunogens that otherwise fail to elicit antibodies with sufficient titers and breadth for broad protection, such as the envelope protein (Env) of HIV. Previously employed targeting strategies often utilize receptor-specific antibodies, however it is impractical to conjugate a bivalent IgG antibody to oligomeric antigens, including HIV Env trimers. Here we designed single chain variable fragment (scFv) and single chain Fab (scFab) constructs of a Clec9A-targeting antibody, expressed as genetically fused conjugates with the soluble ectodomain of Env, gp140. This conjugation did not affect the presentation of Env neutralising antibody epitopes. The scFab moiety was shown to be more stable than scFv, and in the context of gp140 fusions, was able to mediate better binding to recombinant and cell surface-expressed Clec9A, although the level of binding to cell-surface Clec9A was lower than that of the anti-Clec9A IgG. However, binding to Clec9A on the surface of DCs was not detected. Mouse immunization experiments suggested that the Clec9A-binding activity of the scFab-gp140 conjugate was insufficient to enhance Env-specific antibody responses. This is an important first proof of principle study demonstrating the conjugation of a scFab to an oligomeric protein antigen, and that an scFab displays better antigen binding than the corresponding scFv. Future developments of this technique that increase the scFab affinity will provide a valuable means to target oligomeric proteins to cell surface antigens of interest, improving vaccine-generated immune responses.
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MESH Headings
- AIDS Vaccines/administration & dosage
- AIDS Vaccines/genetics
- AIDS Vaccines/immunology
- Animals
- Antibodies, Neutralizing/immunology
- Antibody Affinity
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Epitopes/immunology
- Female
- HEK293 Cells
- HIV Antibodies/immunology
- HIV Infections/immunology
- HIV Infections/therapy
- HIV Infections/virology
- Humans
- Immunogenicity, Vaccine
- Lectins, C-Type/immunology
- Lectins, C-Type/metabolism
- Mice
- Proof of Concept Study
- Protein Domains/genetics
- Protein Domains/immunology
- Receptors, Mitogen/immunology
- Receptors, Mitogen/metabolism
- Recombinant Fusion Proteins/administration & dosage
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/immunology
- Single-Chain Antibodies/administration & dosage
- Single-Chain Antibodies/genetics
- Single-Chain Antibodies/immunology
- Vaccination/methods
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/genetics
- Vaccines, DNA/immunology
- env Gene Products, Human Immunodeficiency Virus/administration & dosage
- env Gene Products, Human Immunodeficiency Virus/genetics
- env Gene Products, Human Immunodeficiency Virus/immunology
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Affiliation(s)
- Hannah A. D. King
- Disease Elimination, Burnet Institute, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher A. Gonelli
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Kirsteen M. Tullett
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Mireille H. Lahoud
- Disease Elimination, Burnet Institute, Melbourne, Victoria, Australia
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Damian F. J. Purcell
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Heidi E. Drummer
- Disease Elimination, Burnet Institute, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Pantelis Poumbourios
- Disease Elimination, Burnet Institute, Melbourne, Victoria, Australia
- Department of Microbiology, Monash University, Melbourne, Victoria, Australia
| | - Rob J. Center
- Disease Elimination, Burnet Institute, Melbourne, Victoria, Australia
- Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- * E-mail:
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Primate immune responses to HIV-1 Env formulated in the saponin-based adjuvant AbISCO-100 in the presence or absence of TLR9 co-stimulation. Sci Rep 2015; 5:8925. [PMID: 25762407 PMCID: PMC4356977 DOI: 10.1038/srep08925] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 02/11/2015] [Indexed: 11/08/2022] Open
Abstract
Protein-based vaccines require adjuvants to achieve optimal responses. Toll-like receptor (TLR) 9 agonists were previously shown to improve responses to protein-based vaccines, such as the Hepatitis B virus vaccine formulated in alum. Here, we used CpG-C together with the clinically relevant saponin-based adjuvant AbISCO-100/Matrix-M (AbISCO), to assess if TLR9 co-stimulation would quantitatively or qualitatively modulate HIV-1 envelope glycoprotein (Env)-specific B and T cell responses in rhesus macaques. The macaques were inoculated with soluble Env trimers in AbISCO, with or without the addition of CpG-C, using an interval similar to the Hepatitis B virus vaccine. Following a comprehensive evaluation of antigen-specific responses in multiple immune compartments, we show that the Env-specific circulating IgG, memory B cells and plasma cells displayed similar kinetics and magnitude in the presence or absence of CpG-C and that there was no apparent difference between the two groups in the elicited HIV-1 neutralizing antibody titers or antigen-specific CD4+ T cell responses. Importantly, the control of SHIV viremia was significantly improved in animals from both Env-immunized groups relative to adjuvant alone controls, demonstrating the potential of AbISCO to act as a stand-alone adjuvant for Env-based vaccines.
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Isik G, Sliepen K, van Montfort T, Sanders RW. Enhanced immunogenicity of HIV-1 envelope gp140 proteins fused to APRIL. PLoS One 2014; 9:e107683. [PMID: 25247707 PMCID: PMC4172553 DOI: 10.1371/journal.pone.0107683] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 08/17/2014] [Indexed: 11/24/2022] Open
Abstract
Current HIV-1 vaccines based on the HIV-1 envelope glycoprotein spike (Env), the only relevant target for broadly neutralizing antibodies, are unable to induce protective immunity. Env immunogenicity can be enhanced by fusion to costimulatory molecules involved in B cell activation, such as APRIL and CD40L. Here, we found that Env-APRIL signaled through the two receptors, BCMA and TACI. In rabbits, Env-APRIL induced significantly higher antibody responses against Env compared to unconjugated Env, while the antibody responses against the APRIL component were negligible. To extend this finding, we tested Env-APRIL in mice and found minimal antibody responses against APRIL. Furthermore, Env-CD40L did not induce significant anti-CD40L responses. Thus, in contrast to the 4-helix cytokines IL-21 and GM-CSF, the TNF-superfamily members CD40L and APRIL induced negligible autoantibodies. This study confirms and extends previous work and shows that fusion of Env-based immunogens to APRIL can improve Env immunogenicity and might help in designing HIV vaccines that induce protective humoral immunity.
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Affiliation(s)
- Gözde Isik
- Laboratory of Experimental Virology, Department of Medical Microbiology Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Kwinten Sliepen
- Laboratory of Experimental Virology, Department of Medical Microbiology Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Thijs van Montfort
- Laboratory of Experimental Virology, Department of Medical Microbiology Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Rogier W. Sanders
- Laboratory of Experimental Virology, Department of Medical Microbiology Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York, United States of America
- * E-mail:
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5
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HIV-1 Env-specific memory and germinal center B cells in C57BL/6 mice. Viruses 2014; 6:3400-14. [PMID: 25198199 PMCID: PMC4189027 DOI: 10.3390/v6093400] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/11/2014] [Accepted: 08/31/2014] [Indexed: 01/16/2023] Open
Abstract
Continued efforts to define the immunogenic properties of the HIV-1 envelope glycoproteins (Env) are needed to elicit effective antibody (Ab) responses by vaccination. HIV-1 is a highly neutralization-resistant virus due to conformational and glycan shielding of conserved Ab determinants on the virus spike. Elicitation of broadly neutralizing Abs that bind poorly accessible epitope regions on Env is therefore extremely challenging and will likely require selective targeting of specific sub-determinants. To evaluate such approaches there is a pressing need for in vivo studies in both large and small animals, including mice. Currently, most mouse immunization studies are performed in the BALB/c strain; however, the C57BL/6 strain offers improved possibilities for mechanistic studies due to the availability of numerous knock-out strains on this genetic background. Here, we compared Env immunogenicity in BALB/c and C57BL/6 mice and found that the magnitude of the antigen-specific response was somewhat lower in C57BL/6 than in BALB/c mice by ELISA but not significantly different by B cell ELISpot measurements. We then established protocols for the isolation of single Env-specific memory B cells and germinal center (GC) B cells from immunized C57BL/6 mice to facilitate future studies of the elicited response at the monoclonal Ab level. We propose that these protocols can be used to gain an improved understanding of the early recruitment of Env-specific B cells to the GC as well as the archiving of such responses in the memory B cell pool following immunization.
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6
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Chatterjee P, Agyemang AF, Alimzhanov MB, Degn S, Tsiftsoglou SA, Alicot E, Jones SA, Ma M, Carroll MC. Complement C4 maintains peripheral B-cell tolerance in a myeloid cell dependent manner. Eur J Immunol 2013; 43:2441-2450. [PMID: 23749435 PMCID: PMC4086186 DOI: 10.1002/eji.201343412] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 04/25/2013] [Accepted: 06/05/2013] [Indexed: 12/14/2022]
Abstract
The factors that allow self-reactive B cells to escape negative selection and become activated remain poorly defined. Using a BCR knock-in mouse strain, we identify a pathway by which B-cell selection to nucleolar self-antigens is complement dependent. Deficiency in complement component C4 led to a breakdown in the elimination of autoreactive B-cell clones at the transitional stage, characterized by a relative increase in their response to a range of stimuli, entrance into follicles, and a greater propensity to form self-reactive GCs. Using mixed BM chimeras, we found that the myeloid compartment was sufficient to restore negative selection in the autoreactive mice. A model is proposed in which in the absence of complement C4, inappropriate clearance of apoptotic debris promotes chronic activation of myeloid cells, allowing the maturation and activation of self-reactive B-cell clones leading to increased spontaneous formation of GCs.
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Affiliation(s)
- Priyadarshini Chatterjee
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Amma F. Agyemang
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
- Graduate Program in Immunology, Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
- MD-PhD Program, Harvard Medical School, Boston, MA, USA
| | - Marat B. Alimzhanov
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Soren Degn
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Stefanos A. Tsiftsoglou
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Elisabeth Alicot
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Sarah A. Jones
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Minghe Ma
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael C. Carroll
- Program in Cellular and Molecular Medicine, Childrens Hospital, Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Graduate Program in Immunology, Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
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7
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Targeting HIV-1 envelope glycoprotein trimers to B cells by using APRIL improves antibody responses. J Virol 2011; 86:2488-500. [PMID: 22205734 DOI: 10.1128/jvi.06259-11] [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
An HIV-1 vaccine remains elusive, in part because various factors limit the quantity and quality of the antibodies raised against the viral envelope glycoprotein complex (Env). We hypothesized that targeting Env vaccines directly to B cells, by fusing them to molecules that bind and activate these cells, would improve Env-specific antibody responses. Therefore, we fused trimeric Env gp140 to A PRoliferation-Inducing Ligand (APRIL), B-cell Activating Factor (BAFF), and CD40 Ligand (CD40L). The Env-APRIL, Env-BAFF, and Env-CD40L gp140 trimers all enhanced the expression of activation-induced cytidine deaminase (AID), the enzyme responsible for inducing somatic hypermutation, antibody affinity maturation, and antibody class switching. They also triggered IgM, IgG, and IgA secretion from human B cells in vitro. The Env-APRIL trimers induced higher anti-Env antibody responses in rabbits, including neutralizing antibodies against tier 1 viruses. The enhanced Env-specific responses were not associated with a general increase in total plasma antibody concentrations, indicating that the effect of APRIL was specific for Env. All the rabbit sera raised against gp140 trimers, irrespective of the presence of CD40L, BAFF, or APRIL, recognized trimeric Env efficiently, whereas sera raised against gp120 monomers did not. The levels of trimer-binding and virus-neutralizing antibodies were strongly correlated, suggesting that gp140 trimers are superior to gp120 monomers as immunogens. Targeting and activating B cells with a trimeric HIV-1 Env-APRIL fusion protein may therefore improve the induction of humoral immunity against HIV-1.
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8
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Melchers M, Matthews K, de Vries RP, Eggink D, van Montfort T, Bontjer I, van de Sandt C, David K, Berkhout B, Moore JP, Sanders RW. A stabilized HIV-1 envelope glycoprotein trimer fused to CD40 ligand targets and activates dendritic cells. Retrovirology 2011; 8:48. [PMID: 21689404 PMCID: PMC3141652 DOI: 10.1186/1742-4690-8-48] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 06/20/2011] [Indexed: 12/22/2022] Open
Abstract
Background One reason why subunit protein and DNA vaccines are often less immunogenic than live-attenuated and whole-inactivated virus vaccines is that they lack the co-stimulatory signals provided by various components of the more complex vaccines. The HIV-1 envelope glycoprotein complex (Env) is no exception to this rule. Other factors that limit the induction of neutralizing antibodies against HIV-1 lie in the structure and instability of Env. We have previously stabilized soluble trimeric mimics of Env by introducing a disulfide bond between gp120 and gp41 and adding a trimer stabilizing mutation in gp41 (SOSIP.R6 gp140). Results We further stabilized the SOSIP.R6 gp140 using a GCN4-based isoleucine zipper motif, creating SOSIP.R6-IZ gp140. In order to target SOSIP.R6-IZ to immune cells, including dendritic cells, while at the same time activating these cells, we fused SOSIP.R6-IZ to the active domain of CD40 ligand (CD40L), which may serve as a 'cis-adjuvant'. The Env component of the SOSIP.R6-IZ-CD40L fusion construct bound to CD4 and neutralizing antibodies, while the CD40L moiety interacted with CD40. Furthermore, the chimeric molecule was able to signal efficiently through CD40 and induce maturation of human dendritic cells. Dendritic cells secreted IL-6, IL-10 and IL-12 in response to stimulation by SOSIP.R6-IZ-CD40L and were able to activate naïve T cells. Conclusions Chimeric HIV-1 gp140 - CD40L trimers can target and activate dendritic cells. Targeting and activating immune cells using CD40L and other 'cis-adjuvants' may improve subunit protein vaccine immunogenicity for HIV-1 and other infectious diseases.
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Affiliation(s)
- Mark Melchers
- Laboratory of Experimental Virology, Department of Medical Microbiology Center for Infection and Immunity Amsterdam, Netherlands
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van Montfort T, Melchers M, Isik G, Menis S, Huang PS, Matthews K, Michael E, Berkhout B, Schief WR, Moore JP, Sanders RW. A chimeric HIV-1 envelope glycoprotein trimer with an embedded granulocyte-macrophage colony-stimulating factor (GM-CSF) domain induces enhanced antibody and T cell responses. J Biol Chem 2011; 286:22250-61. [PMID: 21515681 DOI: 10.1074/jbc.m111.229625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
An effective HIV-1 vaccine should ideally induce strong humoral and cellular immune responses that provide sterilizing immunity over a prolonged period. Current HIV-1 vaccines have failed in inducing such immunity. The viral envelope glycoprotein complex (Env) can be targeted by neutralizing antibodies to block infection, but several Env properties limit the ability to induce an antibody response of sufficient quantity and quality. We hypothesized that Env immunogenicity could be improved by embedding an immunostimulatory protein domain within its sequence. A stabilized Env trimer was therefore engineered with the granulocyte-macrophage colony-stimulating factor (GM-CSF) inserted into the V1V2 domain of gp120. Probing with neutralizing antibodies showed that both the Env and GM-CSF components of the chimeric protein were folded correctly. Furthermore, the embedded GM-CSF domain was functional as a cytokine in vitro. Mouse immunization studies demonstrated that chimeric Env(GM-CSF) enhanced Env-specific antibody and T cell responses compared with wild-type Env. Collectively, these results show that targeting and activation of immune cells using engineered cytokine domains within the protein can improve the immunogenicity of Env subunit vaccines.
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Affiliation(s)
- Thijs van Montfort
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
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C3d adjuvant activity is reduced by altering residues involved in the electronegative binding of C3d to CR2. Immunol Lett 2010; 129:32-8. [PMID: 20064559 DOI: 10.1016/j.imlet.2009.12.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2009] [Revised: 12/19/2009] [Accepted: 12/21/2009] [Indexed: 11/18/2022]
Abstract
The final degradation product of the complement protein C3, C3d, has been used as a molecular adjuvant to various antigens. Chimera proteins of the antigen and multiple copies of C3d were developed to test the adjuvant effect of this molecule. The main mechanism by which C3d enhances the immune response is interaction with CR2. In vitro studies showed that the avidity of C3d for CR2 is affected by residues located at the interacting surface (e.g. 170N) as well as by residues located in other areas. The role of the latter residues has been proposed to depend on the electrostatic nature of the C3d-CR2 interaction, where the charges of the whole molecules are responsible for their binding. C3d is primarily a negatively charged molecule, while CR2 is a positive one. Previous experiments demonstrated that elimination of a positive charge (K162A) in C3d enhanced its avidity for CR2, while elimination of negative charges or addition positives ones (D163A, N170R, respectively), impaired the avidity for CR2. Despite the extensive in vitro research, the role of these residues in the adjuvant effect of C3d is unclear. To study the role of residues at the interacting and non-interacting surface of C3d on the adjuvanticity, single as well as a double residue substitutions were engineered in the murine C3d (R162A, D163A, N170R and D163A-N170R) gene. Two copies of these mutant molecules were fused to HIV-1 Env(gp120) and the proteins were tested for their avidity to bind CR2 (sCR2). Later, these DNA constructs were tested in mice to determine their adjuvant capability. Mutation at residue 162 (R162A) neither enhanced nor impaired the avidity of Env(gp120)-C3d(2) for sCR2 in vitro. Mutations at residues D163A and N170R, on the other hand, reduced the binding affinity of Env(gp120)-C3d(2) for sCR2. Furthermore, these mutations synergized and abolished the interaction of C3d for CR2. The data correlated with the adjuvant capability of these molecules in the mouse model. In summary, residues that alter the electronegative status of C3d (D163A and N170R) impair the binding of chimera proteins to CR2, reducing the adjuvant activity of this molecule.
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Granados-Gonzalez V, Claret J, Berlier W, Vincent N, Urcuqui-Inchima S, Lucht F, Defontaine C, Pinter A, Genin C, Riffard S. Opposite immune reactivity of serum IgG and secretory IgA to conformational recombinant proteins mimicking V1/V2 domains of three different HIV type 1 subtypes depending on glycosylation. AIDS Res Hum Retroviruses 2008; 24:289-99. [PMID: 18260782 DOI: 10.1089/aid.2007.0187] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The V1/V2 domain of the HIV-1 gp120 envelope protein has been shown to contribute to viral cell tropism during infection and also to viral recognition by neutralizing monoclonal antibodies. However, this domain has been poorly investigated. Carbohydrates have been demonstrated to dramatically influence immune reactivity of antisera to viral glycoprotein antigens. In this study, DNA sequences coding for V1/V2 domains from HIV-1 primary isolates of three subtypes (A, B, and C) were subcloned into a secretion vector and used to transfect CHO cells that are able to achieve the glycosylation of proteins. The structure of purified recombinant V1/V2 proteins was tested using two anti-V1/V2 monoclonal antibodies directed against either a linear or a conformational and glycosylation-dependent epitope (8.22.2 and 697-D). Serum or saliva of 14/82 seropositive patients with anti-V1/V2 reactivity demonstrated good recognition of the recombinant proteins. Deglycosylation of the recombinant proteins was found to increase the reactivity of the serum IgG to the clade A and C but not to clade B V1/V2 domain demonstrating that the recognition of glycosylation sites by serum IgG is clade dependent. When considering SIgA from parotid saliva, deglycosylation of all recombinant proteins tested decreased the reactivity, suggesting that glycosylation plays an important role in the recognition of V1/V2 domain target epitopes by this class of antibodies. In conclusion, these results suggest the influence of carbohydrate moieties on the specificity of the antibodies to the V1/V2 domain produced during HIV infection and the potential importance of viral glycans in vaccine responses after mucosal administration.
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Affiliation(s)
- Viviana Granados-Gonzalez
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Julien Claret
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Willy Berlier
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Nadine Vincent
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | | | - Frederic Lucht
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Christiane Defontaine
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Abraham Pinter
- Laboratory of Retroviral Virology, Public Health Research Institute, Newark, New Jersey
| | - Christian Genin
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
| | - Serge Riffard
- Groupe Immunité des Muqueuses et Agents Pathogènes, EA 3064, University of Saint Etienne, Saint Etienne, France
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Complement C3d conjugation to anthrax protective antigen promotes a rapid, sustained, and protective antibody response. PLoS One 2007; 2:e1044. [PMID: 17940608 PMCID: PMC2001179 DOI: 10.1371/journal.pone.0001044] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Accepted: 09/11/2007] [Indexed: 11/19/2022] Open
Abstract
B. anthracis is the causative agent of anthrax. Pathogenesis is primarily mediated through the exotoxins lethal factor and edema factor, which bind protective antigen (PA) to gain entry into the host cell. The current anthrax vaccine (AVA, Biothrax™) consists of aluminum-adsorbed cell-free filtrates of unencapsulated B. anthracis, wherein PA is thought to be the principle target of neutralization. In this study, we evaluated the efficacy of the natural adjuvant, C3d, versus alum in eliciting an anti-PA humoral response and found that C3d conjugation to PA and emulsion in incomplete Freund's adjuvant (IFA) imparted superior protection from anthrax challenge relative to PA in IFA or PA adsorbed to alum. Relative to alum-PA, immunization of mice with C3d-PA/IFA augmented both the onset and sustained production of PA-specific antibodies, including neutralizing antibodies to the receptor-binding portion (domain 4) of PA. C3d-PA/IFA was efficacious when administered either i.p. or s.c., and in adolescent mice lacking a fully mature B cell compartment. Induction of PA-specific antibodies by C3d-PA/IFA correlated with increased efficiency of germinal center formation and plasma cell generation. Importantly, C3d-PA immunization effectively protected mice from intranasal challenge with B. anthracis spores, and was approximately 10-fold more effective than alum-PA immunization or PA/IFA based on dose challenge. These data suggest that incorporation of C3d as an adjuvant may overcome shortcomings of the currently licensed aluminum-based vaccine, and may confer protection in the early days following acute anthrax exposure.
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