1
|
Ripoll DR, Chaudhury S, Wallqvist A. Using the antibody-antigen binding interface to train image-based deep neural networks for antibody-epitope classification. PLoS Comput Biol 2021; 17:e1008864. [PMID: 33780441 PMCID: PMC8032195 DOI: 10.1371/journal.pcbi.1008864] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 04/08/2021] [Accepted: 03/10/2021] [Indexed: 12/05/2022] Open
Abstract
High-throughput B-cell sequencing has opened up new avenues for investigating complex mechanisms underlying our adaptive immune response. These technological advances drive data generation and the need to mine and analyze the information contained in these large datasets, in particular the identification of therapeutic antibodies (Abs) or those associated with disease exposure and protection. Here, we describe our efforts to use artificial intelligence (AI)-based image-analyses for prospective classification of Abs based solely on sequence information. We hypothesized that Abs recognizing the same part of an antigen share a limited set of features at the binding interface, and that the binding site regions of these Abs share share common structure and physicochemical property patterns that can serve as a "fingerprint" to recognize uncharacterized Abs. We combined large-scale sequence-based protein-structure predictions to generate ensembles of 3-D Ab models, reduced the Ab binding interface to a 2-D image (fingerprint), used pre-trained convolutional neural networks to extract features, and trained deep neural networks (DNNs) to classify Abs. We evaluated this approach using Ab sequences derived from human HIV and Ebola viral infections to differentiate between two Abs, Abs belonging to specific B-cell family lineages, and Abs with different epitope preferences. In addition, we explored a different type of DNN method to detect one class of Abs from a larger pool of Abs. Testing on Ab sets that had been kept aside during model training, we achieved average prediction accuracies ranging from 71-96% depending on the complexity of the classification task. The high level of accuracies reached during these classification tests suggests that the DNN models were able to learn a series of structural patterns shared by Abs belonging to the same class. The developed methodology provides a means to apply AI-based image recognition techniques to analyze high-throughput B-cell sequencing datasets (repertoires) for Ab classification.
Collapse
Affiliation(s)
- Daniel R. Ripoll
- DoD Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, Maryland, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF), Bethesda, Maryland, United States of America
| | - Sidhartha Chaudhury
- DoD Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, Maryland, United States of America
- Center for Enabling Capabilities, Walter Reed Army Institute of Research, Silver Spring, Maryland, United States of America
| | - Anders Wallqvist
- DoD Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, Maryland, United States of America
| |
Collapse
|
2
|
Martín-Galiano AJ, McConnell MJ. Using Omics Technologies and Systems Biology to Identify Epitope Targets for the Development of Monoclonal Antibodies Against Antibiotic-Resistant Bacteria. Front Immunol 2019; 10:2841. [PMID: 31921119 PMCID: PMC6914692 DOI: 10.3389/fimmu.2019.02841] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 11/19/2019] [Indexed: 12/12/2022] Open
Abstract
Over the past few decades, antimicrobial resistance has emerged as an important threat to public health due to the global dissemination of multidrug-resistant strains from several bacterial species. This worrisome trend, in addition to the paucity of new antibiotics with novel mechanisms of action in the development pipeline, warrants the development of non-antimicrobial approaches to combating infection caused by these isolates. Monoclonal antibodies (mAbs) have emerged as highly effective molecules for the treatment of multiple diseases. However, in spite of the fact that antibodies play an important role in protective immunity against bacteria, only three mAb therapies have been approved for clinical use in the treatment of bacterial infections. In the present review, we briefly outline the therapeutic potential of mAbs in the treatment of bacterial diseases and discuss how their development can be facilitated when assisted by “omics” technologies and interpreted under a systems biology paradigm. Specifically, methods employing large genomic, transcriptomic, structural, and proteomic datasets allow for the rational identification of epitopes. Ideally, these include those that are present in the majority of circulating isolates, highly conserved at the amino acid level, surface-exposed, located on antigens essential for virulence, and expressed during critical stages of infection. Therefore, these knowledge-based approaches can contribute to the identification of high-value epitopes for the development of effective mAbs against challenging bacterial clones.
Collapse
Affiliation(s)
- Antonio J Martín-Galiano
- Intrahospital Infections Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Spain
| | - Michael J McConnell
- Intrahospital Infections Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Spain
| |
Collapse
|
3
|
Van Regenmortel MHV. Development of a Preventive HIV Vaccine Requires Solving Inverse Problems Which Is Unattainable by Rational Vaccine Design. Front Immunol 2018; 8:2009. [PMID: 29387066 PMCID: PMC5776009 DOI: 10.3389/fimmu.2017.02009] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 12/27/2017] [Indexed: 01/08/2023] Open
Abstract
Hypotheses and theories are essential constituents of the scientific method. Many vaccinologists are unaware that the problems they try to solve are mostly inverse problems that consist in imagining what could bring about a desired outcome. An inverse problem starts with the result and tries to guess what are the multiple causes that could have produced it. Compared to the usual direct scientific problems that start with the causes and derive or calculate the results using deductive reasoning and known mechanisms, solving an inverse problem uses a less reliable inductive approach and requires the development of a theoretical model that may have different solutions or none at all. Unsuccessful attempts to solve inverse problems in HIV vaccinology by reductionist methods, systems biology and structure-based reverse vaccinology are described. The popular strategy known as rational vaccine design is unable to solve the multiple inverse problems faced by HIV vaccine developers. The term “rational” is derived from “rational drug design” which uses the 3D structure of a biological target for designing molecules that will selectively bind to it and inhibit its biological activity. In vaccine design, however, the word “rational” simply means that the investigator is concentrating on parts of the system for which molecular information is available. The economist and Nobel laureate Herbert Simon introduced the concept of “bounded rationality” to explain why the complexity of the world economic system makes it impossible, for instance, to predict an event like the financial crash of 2007–2008. Humans always operate under unavoidable constraints such as insufficient information, a limited capacity to process huge amounts of data and a limited amount of time available to reach a decision. Such limitations always prevent us from achieving the complete understanding and optimization of a complex system that would be needed to achieve a truly rational design process. This is why the complexity of the human immune system prevents us from rationally designing an HIV vaccine by solving inverse problems.
Collapse
|
4
|
Schrader JW, McLean GR. Multispecificity of a recombinant anti-ras monoclonal antibody. J Mol Recognit 2017; 31. [DOI: 10.1002/jmr.2683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/23/2017] [Accepted: 09/27/2017] [Indexed: 01/02/2023]
Affiliation(s)
- John W. Schrader
- The Biomedical Research Centre; University of British Columbia; Vancouver BC Canada
| | - Gary R. McLean
- Cellular and Molecular Immunology Research Centre; London Metropolitan University; London UK
- National Heart and Lung Institute; Imperial College London; London UK
| |
Collapse
|
5
|
Duan Q, Lee KH, Nandre RM, Garcia C, Chen J, Zhang W. MEFA (multiepitope fusion antigen)-Novel Technology for Structural Vaccinology, Proof from Computational and Empirical Immunogenicity Characterization of an Enterotoxigenic Escherichia coli (ETEC) Adhesin MEFA. ACTA ACUST UNITED AC 2017; 8. [PMID: 28944092 PMCID: PMC5606245 DOI: 10.4172/2157-7560.1000367] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Vaccine development often encounters the challenge of virulence heterogeneity. Enterotoxigenic Escherichia coli (ETEC) bacteria producing immunologically heterogeneous virulence factors are a leading cause of children's diarrhea and travelers' diarrhea. Currently, we do not have licensed vaccines against ETEC bacteria. While conventional methods continue to make progress but encounter challenge, new computational and structure-based approaches are explored to accelerate ETEC vaccine development. In this study, we applied a structural vaccinology concept to construct a structure-based multiepitope fusion antigen (MEFA) to carry representing epitopes of the seven most important ETEC adhesins [CFA/I, CFA/II (CS1-CS3), CFA/IV (CS4-CS6)], simulated antigenic structure of the CFA/I/II/IV MEFA with computational atomistic modeling and simulation, characterized immunogenicity in mouse immunization, and examined the potential of structure-informed vaccine design for ETEC vaccine development. A tag-less recombinant MEFA protein (CFA/I/II/IV MEFA) was effectively expressed and extracted. Molecular dynamics simulations indicated that this MEFA immunogen maintained a stable secondary structure and presented epitopes on the protein surface. Empirical data showed that mice immunized with the tagless CFA/I/II/IV MEFA developed strong antigen-specific antibody responses, and mouse serum antibodies significantly inhibited in vitro adherence of bacteria expressing these seven adhesins. These results revealed congruence of antigen immunogenicity between computational simulation and empirical mouse immunization and indicated this tag-less CFA/I/II/IV MEFA potentially an antigen for a broadly protective ETEC vaccine, suggesting a potential application of MEFA-based structural vaccinology for vaccine design against ETEC and likely other pathogens.
Collapse
Affiliation(s)
- Qiangde Duan
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA
| | - Kuo Hao Lee
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
| | - Rahul M Nandre
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA
| | - Carolina Garcia
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA
| | - Jianhan Chen
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, KS 66506, USA
| | - Weiping Zhang
- Department of Diagnostic Medicine/Pathobiology, Kansas State University College of Veterinary Medicine, Manhattan, KS 66506, USA
| |
Collapse
|
6
|
Van Regenmortel MHV. Structure-Based Reverse Vaccinology Failed in the Case of HIV Because it Disregarded Accepted Immunological Theory. Int J Mol Sci 2016; 17:E1591. [PMID: 27657055 PMCID: PMC5037856 DOI: 10.3390/ijms17091591] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/30/2016] [Accepted: 09/07/2016] [Indexed: 12/14/2022] Open
Abstract
Two types of reverse vaccinology (RV) should be distinguished: genome-based RV for bacterial vaccines and structure-based RV for viral vaccines. Structure-based RV consists in trying to generate a vaccine by first determining the crystallographic structure of a complex between a viral epitope and a neutralizing monoclonal antibody (nMab) and then reconstructing the epitope by reverse molecular engineering outside the context of the native viral protein. It is based on the unwarranted assumption that the epitope designed to fit the nMab will have acquired the immunogenic capacity to elicit a polyclonal antibody response with the same protective capacity as the nMab. After more than a decade of intensive research using this type of RV, this approach has failed to deliver an effective, preventive HIV-1 vaccine. The structure and dynamics of different types of HIV-1 epitopes and of paratopes are described. The rational design of an anti-HIV-1 vaccine is shown to be a misnomer since investigators who claim that they design a vaccine are actually only improving the antigenic binding capacity of one epitope with respect to only one paratope and not the immunogenic capacity of an epitope to elicit neutralizing antibodies. Because of the degeneracy of the immune system and the polyspecificity of antibodies, each epitope studied by the structure-based RV procedure is only one of the many epitopes that the particular nMab is able to recognize and there is no reason to assume that this nMab must have been elicited by this one epitope of known structure. Recent evidence is presented that the trimeric Env spikes of the virus possess such an enormous plasticity and intrinsic structural flexibility that it is it extremely difficult to determine which Env regions are the best candidate vaccine immunogens most likely to elicit protective antibodies.
Collapse
Affiliation(s)
- Marc H V Van Regenmortel
- UMR 7242 Biotechnologie et Signalisation Cellulaire, Université de Strasbourg-CNRS, 300, Boulevard Sébastien Brant, CS 10413, 67412 Illkirch Cedex, France.
| |
Collapse
|
7
|
Van Regenmortel MHV. Commentary: Basic Research in HIV Vaccinology Is Hampered by Reductionist Thinking. Front Immunol 2016; 7:266. [PMID: 27458032 PMCID: PMC4932109 DOI: 10.3389/fimmu.2016.00266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/22/2016] [Indexed: 11/29/2022] Open
|
8
|
Van Regenmortel MHV. Editorial: Paradigm Changes are Required in HIV Vaccine Research. Front Immunol 2015; 6:326. [PMID: 26157442 PMCID: PMC4477177 DOI: 10.3389/fimmu.2015.00326] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 06/10/2015] [Indexed: 01/08/2023] Open
Affiliation(s)
- Marc H V Van Regenmortel
- CNRS, UMR 7242 Biotechnologie et Signalisation Cellulaire, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), Ecole Supérieure de Biotechnologie Strasbourg (ESBS), University of Strasbourg , Illkirch , France
| |
Collapse
|
9
|
Van Regenmortel MHV. Specificity, polyspecificity, and heterospecificity of antibody-antigen recognition. J Mol Recognit 2015; 27:627-39. [PMID: 25277087 DOI: 10.1002/jmr.2394] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 11/09/2022]
Abstract
The concept of antibody specificity is analyzed and shown to reside in the ability of an antibody to discriminate between two antigens. Initially, antibody specificity was attributed to sequence differences in complementarity determining regions (CDRs), but as increasing numbers of crystallographic antibody-antigen complexes were elucidated, specificity was analyzed in terms of six antigen-binding regions (ABRs) that only roughly correspond to CDRs. It was found that each ABR differs significantly in its amino acid composition and tends to bind different types of amino acids at the surface of proteins. In spite of these differences, the combined preference of the six ABRs does not allow epitopes to be distinguished from the rest of the protein surface. These findings explain the poor success of past and newly proposed methods for predicting protein epitopes. Antibody polyspecificity refers to the ability of one antibody to bind a large variety of epitopes in different antigens, and this property explains how the immune system develops an antibody repertoire that is able to recognize every antigen the system is likely to encounter. Antibody heterospecificity arises when an antibody reacts better with another antigen than with the one used to raise the antibody. As a result, an antibody may sometimes appear to have been elicited by an antigen with which it is unable to react. The implications of antibody polyspecificity and heterospecificity in vaccine development are pointed out.
Collapse
Affiliation(s)
- Marc H V Van Regenmortel
- Wallenberg Research Center, Stellenbosch Institute for Advanced Study, Stellenbosch University, Stellenbosch, South Africa
| |
Collapse
|
10
|
Van Regenmortel MHV. Why Does the Molecular Structure of Broadly Neutralizing Monoclonal Antibodies Isolated from Individuals Infected with HIV-1 not Inform the Rational Design of an HIV-1 Vaccine? AIMS Public Health 2015; 2:183-193. [PMID: 29546103 PMCID: PMC5690275 DOI: 10.3934/publichealth.2015.2.183] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/28/2015] [Indexed: 01/12/2023] Open
Abstract
It is commonly assumed that neutralizing Mabs that bind to the HIV-1 Env glycoprotein are more specific reagents than anti-HIV-1 polyclonal antisera and that knowledge of the structure of these Mabs facilitates the rational design of effective HIV-1 vaccine immunogens. However, after more than ten years of unsuccessful experimentation using the structure-based reverse vaccinology approach, it is now evident that it is not possible to infer from the structure of neutralizing Mabs which HIV immunogens induced their formation nor which vaccine immunogens will elicit similar Abs in an immunized host. The use of Mabs for developing an HIV-1 vaccine was counterproductive because it overlooked the fact that the apparent specificity of a Mab very much depends on the selection procedure used to obtain it and also did not take into account that an antibody is never monospecific for a single epitope but is always polyspecific for many epitopes. When the rationale of the proponents of the unsuccessful rational design strategy is analyzed, it appears that investigators who claim they are designing a vaccine immunogen are only improving the binding reactivity of a single epitope-paratope pair and are not actually designing an immunogen able to generate protective antibodies. The task of a designer consists in imagining what type of immunogen is likely to elicit a protective immune response but in the absence of knowledge regarding which features of the immune system are responsible for producing a functional neutralizing activity in antibodies, it is not feasible to intentionally optimize a potential immunogen candidate in order to obtain the desired outcome. The only available option is actually to test possible solutions by trial-and-error experiments until the preset goal is perhaps attained. Rational design and empirical approaches in HIV vaccine research should thus not be opposed as alternative options since empirical testing is an integral part of a so-called design strategy.
Collapse
Affiliation(s)
- Marc H V Van Regenmortel
- CNRS, UMR7242 - Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), Université de Strasbourg, Illkirch 67400, France ; Tel: +27-793376766
| |
Collapse
|
11
|
|
12
|
Van Regenmortel MHV. An Outdated Notion of Antibody Specificity is One of the Major Detrimental Assumptions of the Structure-Based Reverse Vaccinology Paradigm, Which Prevented It from Helping to Develop an Effective HIV-1 Vaccine. Front Immunol 2014; 5:593. [PMID: 25477882 PMCID: PMC4235417 DOI: 10.3389/fimmu.2014.00593] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 11/05/2014] [Indexed: 01/12/2023] Open
Abstract
The importance of paradigms for guiding scientific research is explained with reference to the seminal work of Karl Popper and Thomas Kuhn. A prevalent paradigm, followed for more than a decade in HIV-1 vaccine research, which gave rise to the strategy known as structure-based reverse vaccinology is described in detail. Several reasons why this paradigm did not allow the development of an effective HIV-1 vaccine are analyzed. A major reason is the belief shared by many vaccinologists that antibodies possess a narrow specificity for a single epitope and are not polyspecific for a diverse group of potential epitopes. When this belief is abandoned, it becomes obvious that the one particular epitope structure observed during the crystallographic analysis of a neutralizing antibody–antigen complex does not necessarily reveal, which immunogenic structure should be used to elicit the same type of neutralizing antibody. In the physical sciences, scientific explanations are usually presented as logical deductions derived from a relevant law of nature together with certain initial conditions. In immunology, causal explanations in terms of a single cause acting according to a law of nature are not possible because numerous factors always play a role in bringing about an effect. The implications of this state of affairs for the rational design of HIV vaccines are outlined. An alternative approach to obtain useful scientific understanding consists in intervening empirically in the immune system and it is suggested that manipulating the system experimentally is needed to learn to control it and achieve protective immunity by vaccination.
Collapse
Affiliation(s)
- Marc H V Van Regenmortel
- CNRS, Biotechnologie des Interactions Moleculaires, IREBS, School of Biotechnology, ESBS, University of Strasbourg , Illkirch , France
| |
Collapse
|
13
|
Envelope variants circulating as initial neutralization breadth developed in two HIV-infected subjects stimulate multiclade neutralizing antibodies in rabbits. J Virol 2014; 88:12949-67. [PMID: 25210191 DOI: 10.1128/jvi.01812-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
UNLABELLED Identifying characteristics of the human immunodeficiency virus type 1 (HIV-1) envelope that are effective in generating broad, protective antibodies remains a hurdle to HIV vaccine design. Emerging evidence of the development of broad and potent neutralizing antibodies in HIV-infected subjects suggests that founder and subsequent progeny viruses may express unique antigenic motifs that contribute to this developmental pathway. We hypothesize that over the course of natural infection, B cells are programmed to develop broad antibodies by exposure to select populations of emerging envelope quasispecies variants. To test this hypothesis, we identified two unrelated subjects whose antibodies demonstrated increasing neutralization breadth against a panel of HIV-1 isolates over time. Full-length functional env genes were cloned longitudinally from these subjects from months after infection through 2.6 to 5.8 years of infection. Motifs associated with the development of breadth in published, cross-sectional studies were found in both subjects. We compared the immunogenicity of envelope vaccines derived from time points obtained during and after broadening of neutralization activity within these subjects. Rabbits were coimmunized four times with selected multiple gp160 DNAs and gp140-trimeric envelope proteins. The affinity of the polyclonal response increased as a function of boosting. The most rapid and persistent neutralization of multiclade tier 1 viruses was elicited by envelopes that were circulating in plasma at time points prior to the development of 50% neutralization breadth in both human subjects. The breadth elicited in rabbits was not improved by exposure to later envelope variants. These data have implications for vaccine development in describing a target time point to identify optimal envelope immunogens. IMPORTANCE Vaccine protection against viral infections correlates with the presence of neutralizing antibodies; thus, vaccine components capable of generating potent neutralization are likely to be critical constituents in an effective HIV vaccine. However, vaccines tested thus far have elicited only weak antibody responses and very modest, waning protection. We hypothesized that B cells develop broad antibodies by exposure to the evolving viral envelope population and tested this concept using multiple envelopes from two subjects who developed neutralization breadth within a few years of infection. We compared different combinations of envelopes from each subject to identify the most effective immunogens and regimens. In each subject, use of HIV envelopes circulating during the early development and maturation of breadth generated more-potent antibodies that were modestly cross neutralizing. These data suggest a new approach to identifying envelope immunogens that may be more effective in generating protective antibodies in humans.
Collapse
|
14
|
Thomas S, Luxon BA. Vaccines based on structure-based design provide protection against infectious diseases. Expert Rev Vaccines 2014; 12:1301-11. [DOI: 10.1586/14760584.2013.840092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
15
|
Sattentau QJ. Envelope Glycoprotein Trimers as HIV-1 Vaccine Immunogens. Vaccines (Basel) 2013; 1:497-512. [PMID: 26344344 PMCID: PMC4494206 DOI: 10.3390/vaccines1040497] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/11/2013] [Accepted: 10/12/2013] [Indexed: 12/15/2022] Open
Abstract
The HIV-1 envelope glycoprotein spike is the target of neutralizing antibody attack, and hence represents the only relevant viral antigen for antibody-based vaccine design. Various approaches have been attempted to recapitulate Env in membrane-anchored and soluble forms, and these will be discussed here in the context of recent successes and challenges still to be overcome.
Collapse
Affiliation(s)
- Quentin J Sattentau
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX13RE, UK.
| |
Collapse
|
16
|
Schiffner T, Sattentau QJ, Dorrell L. Development of prophylactic vaccines against HIV-1. Retrovirology 2013; 10:72. [PMID: 23866844 PMCID: PMC3722125 DOI: 10.1186/1742-4690-10-72] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/11/2013] [Indexed: 01/12/2023] Open
Abstract
The focus of most current HIV-1 vaccine development is on antibody-based approaches. This is because certain antibody responses correlated with protection from HIV-1 acquisition in the RV144 phase III trial, and because a series of potent and broad spectrum neutralizing antibodies have been isolated from infected individuals. Taken together, these two findings suggest ways forward to develop a neutralizing antibody-based vaccine. However, understanding of the correlates of protection from disease in HIV-1 and other infections strongly suggests that we should not ignore CTL-based research. Here we review recent progress in the field and highlight the challenges implicit in HIV-1 vaccine design and some potential solutions.
Collapse
Affiliation(s)
- Torben Schiffner
- The Sir William Dunn School of Pathology, The University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | | | | |
Collapse
|
17
|
A brief history of the global effort to develop a preventive HIV vaccine. Vaccine 2013; 31:3502-18. [PMID: 23707164 DOI: 10.1016/j.vaccine.2013.05.018] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 05/01/2013] [Accepted: 05/07/2013] [Indexed: 01/09/2023]
Abstract
Soon after HIV was discovered as the cause of AIDS in 1983-1984, there was an expectation that a preventive vaccine would be rapidly developed. In trying to achieve that goal, three successive scientific paradigms have been explored: induction of neutralizing antibodies, induction of cell mediated immunity, and exploration of combination approaches and novel concepts. Although major progress has been made in understanding the scientific basis for HIV vaccine development, efficacy trials have been critical in moving the field forward. In 2009, the field was reinvigorated with the modest results obtained from the RV144 trial conducted in Thailand. Here, we review those vaccine development efforts, with an emphasis on events that occurred during the earlier years. The goal is to provide younger generations of scientists with information and inspiration to continue the search for an HIV vaccine.
Collapse
|
18
|
Shi C, Ploss A. Hepatitis C virus vaccines in the era of new direct-acting antivirals. Expert Rev Gastroenterol Hepatol 2013; 7:171-85. [PMID: 23363265 DOI: 10.1586/egh.12.72] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Hepatitis C virus (HCV) infection is a major global health problem as it has a high propensity for establishing chronicity. Chronic HCV carriers are at risk of developing severe liver disease including fibrosis, cirrhosis and liver cancer. While treatment has considerably improved over the years, therapy is still only partially effective, and is plagued by side effects, which contribute to treatment failure and is expensive to manage. The drug development pipeline contains several compounds that hold promise to achieve the goal of a short and more tolerable therapy, and are also likely to improve treatment response rates. It remains to be seen, however, how potent antiviral drug cocktails will affect the hepatitis C burden worldwide. In resource-poor environments, considerable costs, inadequate infrastructure for medical supervision and distribution may diminish the impact of future therapies. Consequently, development of novel therapeutic and prophylactic strategies is imperative to contain HCV infection globally.
Collapse
Affiliation(s)
- Chao Shi
- Laboratory of Virology and Infectious Disease, Center for the Study of Hepatitis C The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | | |
Collapse
|
19
|
Planque SA, Mitsuda Y, Nishiyama Y, Karle S, Boivin S, Salas M, Morris MK, Hara M, Liao G, Massey RJ, Hanson CV, Paul S. Antibodies to a superantigenic glycoprotein 120 epitope as the basis for developing an HIV vaccine. THE JOURNAL OF IMMUNOLOGY 2012; 189:5367-81. [PMID: 23089396 DOI: 10.4049/jimmunol.1200981] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Failure to induce synthesis of neutralizing Abs to the CD4 binding determinant (CD4BD) of gp120, a central objective in HIV vaccine research, has been alternately ascribed to insufficient immunogen binding to Abs in their germline V region configuration expressed as BCRs, insufficient adaptive mutations in Ab V regions, and conformational instability of gp120. We employed peptide analogs of gp120 residues 421-433 within the CD4BD (CD4BD(core)) to identify Abs produced without prior exposure to HIV (constitutive Abs). The CD4BD(core) peptide was recognized by single-chain Fv fragments from noninfected humans with lupus that neutralized genetically diverse strains belonging to various HIV subtypes. Replacing the framework region (FR) of a V(H)4-family single-chain Fv with the corresponding V(H)3-family FRs from single-chain Fv JL427 improved the CD4BD(core) peptide-binding activity, suggesting a CD4BD(core) binding site outside the pocket formed by the CDRs. Replacement mutations in the FR site vicinity suggested the potential for adaptive improvement. A very small subset of serum CD4BD(core)-specific serum IgAs from noninfected humans without autoimmune disease isolated by epitope-specific chromatography neutralized the virus potently. A CD4BD(core)-specific, HIV neutralizing murine IgM with H and L chain V regions (V(H) and V(L) regions) free of immunogen-driven somatic mutations was induced by immunization with a CD4BD(core) peptide analog containing an electrophilic group that binds B cells covalently. The studies indicate broad and potent HIV neutralization by constitutive Abs as an innate, germline-encoded activity directed to the superantigenic CD4BD(core) epitope that is available for amplification for vaccination against HIV.
Collapse
Affiliation(s)
- Stephanie A Planque
- Department of Pathology and Laboratory Medicine, Chemical Immunology Research Center, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Demberg T, Robert-Guroff M. Controlling the HIV/AIDS epidemic: current status and global challenges. Front Immunol 2012; 3:250. [PMID: 22912636 PMCID: PMC3418522 DOI: 10.3389/fimmu.2012.00250] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 07/27/2012] [Indexed: 12/21/2022] Open
Abstract
This review provides an overview of the current status of the global HIV pandemic and strategies to bring it under control. It updates numerous preventive approaches including behavioral interventions, male circumcision (MC), pre- and post-exposure prophylaxis (PREP and PEP), vaccines, and microbicides. The manuscript summarizes current anti-retroviral treatment options, their impact in the western world, and difficulties faced by emerging and resource-limited nations in providing and maintaining appropriate treatment regimens. Current clinical and pre-clinical approaches toward a cure for HIV are described, including new drug compounds that target viral reservoirs and gene therapy approaches aimed at altering susceptibility to HIV infection. Recent progress in vaccine development is summarized, including novel approaches and new discoveries.
Collapse
Affiliation(s)
- Thorsten Demberg
- Vaccine Branch, Section on Immune Biology of Retroviral Infection, National Cancer Institute, National Institutes of Health Bethesda, MD, USA
| | | |
Collapse
|
21
|
Van Regenmortel MHV. Basic research in HIV vaccinology is hampered by reductionist thinking. Front Immunol 2012; 3:194. [PMID: 22787464 PMCID: PMC3391733 DOI: 10.3389/fimmu.2012.00194] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 06/21/2012] [Indexed: 01/05/2023] Open
Abstract
This review describes the structure-based reverse vaccinology approach aimed at developing vaccine immunogens capable of inducing antibodies that broadly neutralize HIV-1. Some basic principles of protein immunochemistry are reviewed and the implications of the extensive polyspecificity of antibodies for vaccine development are underlined. Although it is natural for investigators to want to know the cause of an effective immunological intervention, the classic notion of causality is shown to have little explanatory value for a system as complex as the immune system, where any observed effect always results from many interactions between a large number of components. Causal explanations are reductive because a single factor is singled out for attention and given undue explanatory weight on its own. Other examples of the negative impact of reductionist thinking on HIV vaccine development are discussed. These include (1) the failure to distinguish between the chemical nature of antigenicity and the biological nature of immunogenicity, (2) the belief that when an HIV-1 epitope is reconstructed by rational design to better fit a neutralizing monoclonal antibody (nMab), this will produce an immunogen able to elicit Abs with the same neutralizing capacity as the Ab used as template for designing the antigen, and (3) the belief that protection against infection can be analyzed at the level of individual molecular interactions although it has meaning only at the level of an entire organism. The numerous unsuccessful strategies that have been used to design HIV-1 vaccine immunogens are described and it is suggested that the convergence of so many negative experimental results justifies the conclusion that reverse vaccinology is unlikely to lead to the development of a preventive HIV-1 vaccine. Immune correlates of protection in vaccines have not yet been identified because this will become feasible only retrospectively once an effective vaccine exists. The finding that extensive antibody affinity maturation is needed to obtain mature anti-HIV-1 Abs endowed with a broad neutralizing capacity explains why antigens designed to fit matured Mabs are not effective vaccine immunogens since these are administered to naive recipients who possess only B-cell receptors corresponding to the germline version of the matured Abs.
Collapse
Affiliation(s)
- Marc H. V. Van Regenmortel
- Stellenbosch Institute of Advanced Study, Wallenberg Research Center at Stellenbosch University,Stellenbosch, South Africa
| |
Collapse
|
22
|
Falconar AKI. Epitope reactions can be gauged by relative antibody discriminating specificity (RADS) values supported by deletion, substitution and cysteine bridge formation analyses: potential uses in pathogenesis studies. BMC Res Notes 2012; 5:208. [PMID: 22546090 PMCID: PMC3392722 DOI: 10.1186/1756-0500-5-208] [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: 10/28/2011] [Accepted: 04/30/2012] [Indexed: 01/05/2023] Open
Abstract
Background Epitope-mapping of infectious agents is essential for pathogenesis studies. Since polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs) are always polyspecific and can react with multiple epitopes, it is important to distinguish between specific and non-specific reactions. Relative antibody discriminating specificity (RADS) values, obtained from their relative ELISA reactions with L-amino acid peptides prepared in the natural versus reverse orientations (x-fold absorbance natural/absorbance reverse = RADS value) may be valuable for this purpose. PAbs generated against the dengue type-2 virus (DENV-2) nonstructural-1 (NS1) glycoprotein candidate vaccine also reacted with both DENV envelope (E) glycoproteins and blood-clotting proteins. New xKGSx/xSGKx amino acid motifs were identified on DENV-2 glycoproteins, HIV-1 gp41 and factor IXa. Their potential roles in DENV and HIV-1 antibody-enhanced replication (AER) and auto-immunity were assessed. In this study, a) RADS values were determined for MAbs and PAbs, generated in congeneic (H2: class II) mice against DENV NS1 glycoprotein epitopes, to account for their cross-reaction patterns, and b) MAb 1G5.3 reactions with xKGSx/xSGKx motifs present in the DENV-4 NS1, E and HIV-1 glycoproteins and factor IXa were assessed after the introduction of amino acid substitutions, deletions, or intra-/inter-cysteine (C-C) bridges. Results MAbs 1H7.4, 5H4.3, 3D1.4 and 1G5.3 had high (4.23- to 16.83-fold) RADS values against single epitopes on the DENV-2 NS1 glycoprotein, and MAb 3D1.4 defined the DENV complex-conserved LX1 epitope. In contrast, MAbs 1G5.4-A1-C3 and 1C6.3 had low (0.47- to 1.67-fold) RADS values against multiple epitopes. PAb DENV complex-reactions occurred through moderately-high (2.77- and 3.11-fold) RADS values against the LX1 epitope. MAb 1G5.3 reacted with xSGKx motifs present in DENV-4 NS1 and E glycoproteins, HIV-1 gp41 and factor IXa, while natural C-C bridge formations or certain amino acid substitutions increased its binding activity. Conclusions These results: i) were readily obtained using a standard 96-well ELISA format, ii) showed the LX1 epitope to be the immuno-dominant DENV complex determinant in the NS1 glycoprotein, iii) supported an antigenic co-evolution of the DENV NS1 and E glycoproteins, and iv) identified methods that made it possible to determine the role of anti-DENV PAb reactions in viral pathogenesis.
Collapse
Affiliation(s)
- Andrew K I Falconar
- Laboratorio de Investigaciones en Enfermedades Tropicales, Departamento de Medicina, Universidad del Norte, Km5 Antigua via Puerto Colombia, Barranquilla, Colombia.
| |
Collapse
|
23
|
Kong L, Sattentau QJ. Antigenicity and Immunogenicity in HIV-1 Antibody-Based Vaccine Design. JOURNAL OF AIDS & CLINICAL RESEARCH 2012; S8:3. [PMID: 23227445 PMCID: PMC3515071 DOI: 10.4172/2155-6113] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neutralizing antibodies can protect from infection by immunodeficiency viruses. However, the induction by active vaccination of antibodies that can potently neutralize a broad range of circulating virus strains is a goal not yet achieved, despite more than 2 decades of research. Here we review progress made in the field, from early empirical studies to today's rational structure-based vaccine antigen design. We discuss the existence of broadly neutralizing antibodies, their implications for epitope discovery and recent progress made in antigen design. Finally, we consider the relationship between antigenicity and immunogenicity for B cell recognition and antibody production, a major hurdle for rational vaccine design to overcome.
Collapse
Affiliation(s)
- Leopold Kong
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
- The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Quentin J Sattentau
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| |
Collapse
|