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Chung SS, Bidstrup EJ, Hershewe JM, Warfel KF, Jewett MC, DeLisa MP. Ribosome Stalling of N-Linked Glycoproteins in Cell-Free Extracts. ACS Synth Biol 2022; 11:3892-3899. [PMID: 36399685 PMCID: PMC9764415 DOI: 10.1021/acssynbio.2c00311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Indexed: 11/21/2022]
Abstract
Ribosome display is a powerful in vitro method for selection and directed evolution of proteins expressed from combinatorial libraries. However, the ability to display proteins with complex post-translational modifications such as glycosylation is limited. To address this gap, we developed a set of complementary methods for producing stalled ribosome complexes that displayed asparagine-linked (N-linked) glycoproteins in conformations amenable to downstream functional and glycostructural interrogation. The ability to generate glycosylated ribosome-nascent chain (glycoRNC) complexes was enabled by integrating SecM-mediated translation arrest with methods for cell-free N-glycoprotein synthesis. This integration enabled a first-in-kind method for ribosome stalling of target proteins modified efficiently and site-specifically with different N-glycan structures. Moreover, the observation that encoding mRNAs remained stably attached to ribosomes provides evidence of a genotype-glycophenotype link between an arrested glycoprotein and its RNA message. We anticipate that our method will enable selection and evolution of N-glycoproteins with advantageous biological and biophysical properties.
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Affiliation(s)
- Sean S. Chung
- Biochemistry,
Molecular and Cell Biology, Cornell University, Ithaca, New York 14853, United States
| | - Erik J. Bidstrup
- Robert
F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Jasmine M. Hershewe
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road Technological Institute E136, Evanston, Illinois 60208-3120, United States
- Center
for Synthetic Biology, Northwestern University, 2145 Sheridan Road Technological
Institute E136, Evanston, Illinois 60208-3120, United States
- Chemistry
of Life Processes Institute, Northwestern
University, 2170 Campus
Drive, Evanston, Illinois 60208-3120, United States
| | - Katherine F. Warfel
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road Technological Institute E136, Evanston, Illinois 60208-3120, United States
- Center
for Synthetic Biology, Northwestern University, 2145 Sheridan Road Technological
Institute E136, Evanston, Illinois 60208-3120, United States
- Chemistry
of Life Processes Institute, Northwestern
University, 2170 Campus
Drive, Evanston, Illinois 60208-3120, United States
| | - Michael C. Jewett
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road Technological Institute E136, Evanston, Illinois 60208-3120, United States
- Center
for Synthetic Biology, Northwestern University, 2145 Sheridan Road Technological
Institute E136, Evanston, Illinois 60208-3120, United States
- Chemistry
of Life Processes Institute, Northwestern
University, 2170 Campus
Drive, Evanston, Illinois 60208-3120, United States
| | - Matthew P. DeLisa
- Biochemistry,
Molecular and Cell Biology, Cornell University, Ithaca, New York 14853, United States
- Robert
F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
- Cornell
Institute
of Biotechnology, Cornell University, Ithaca, New York 14853, United States
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2
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Stark JC, Jaroentomeechai T, Moeller TD, Hershewe JM, Warfel KF, Moricz BS, Martini AM, Dubner RS, Hsu KJ, Stevenson TC, Jones BD, DeLisa MP, Jewett MC. On-demand biomanufacturing of protective conjugate vaccines. SCIENCE ADVANCES 2021; 7:eabe9444. [PMID: 33536221 PMCID: PMC7857678 DOI: 10.1126/sciadv.abe9444] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/18/2020] [Indexed: 05/19/2023]
Abstract
Conjugate vaccines are among the most effective methods for preventing bacterial infections. However, existing manufacturing approaches limit access to conjugate vaccines due to centralized production and cold chain distribution requirements. To address these limitations, we developed a modular technology for in vitro conjugate vaccine expression (iVAX) in portable, freeze-dried lysates from detoxified, nonpathogenic Escherichia coli. Upon rehydration, iVAX reactions synthesize clinically relevant doses of conjugate vaccines against diverse bacterial pathogens in 1 hour. We show that iVAX-synthesized vaccines against Francisella tularensis subsp. tularensis (type A) strain Schu S4 protected mice from lethal intranasal F. tularensis challenge. The iVAX platform promises to accelerate development of new conjugate vaccines with increased access through refrigeration-independent distribution and portable production.
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Affiliation(s)
- Jessica C Stark
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208-3120, USA
| | - Thapakorn Jaroentomeechai
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, NY 14853, USA
| | - Tyler D Moeller
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, NY 14853, USA
| | - Jasmine M Hershewe
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208-3120, USA
| | - Katherine F Warfel
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208-3120, USA
| | - Bridget S Moricz
- Department of Microbiology and Immunology, University of Iowa, 51 Newton Rd 3-403 Bowen Science Building, Iowa City, IA 52242, USA
| | - Anthony M Martini
- Department of Microbiology and Immunology, University of Iowa, 51 Newton Rd 3-403 Bowen Science Building, Iowa City, IA 52242, USA
| | - Rachel S Dubner
- Department of Biological Sciences, Northwestern University, 2205 Tech Drive Hogan Hall 2144, Evanston, IL 60208-3500, USA
| | - Karen J Hsu
- Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Rd Technological Institute B224, Evanston, IL 60208-3120, USA
| | - Taylor C Stevenson
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Weill Hall, Ithaca, NY 14853, USA
| | - Bradley D Jones
- Department of Microbiology and Immunology, University of Iowa, 51 Newton Rd 3-403 Bowen Science Building, Iowa City, IA 52242, USA
- Graduate Program in Genetics, 431 Newton Rd, University of Iowa, Iowa City, IA 52242, USA
| | - Matthew P DeLisa
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, 120 Olin Hall, Ithaca, NY 14853, USA.
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Weill Hall, Ithaca, NY 14853, USA
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA.
- Center for Synthetic Biology, Northwestern University, 2145 Sheridan Rd Technological Institute E136, Evanston, IL 60208-3120, USA
- Chemistry of Life Processes Institute, Northwestern University, 2170 Campus Drive, Evanston, IL 60208-3120, USA
- Robert H. Lurie Comprehensive Cancer Center, Northwestern University, 676 N. St Clair St, Suite 1200, Chicago, IL 60611-3068, USA
- Simpson-Querrey Institute, Northwestern University, 303 E. Superior St, Suite 11-131 Chicago, IL 60611-2875, USA
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3
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Glycoconjugate vaccine using a genetically modified O antigen induces protective antibodies to Francisella tularensis. Proc Natl Acad Sci U S A 2019; 116:7062-7070. [PMID: 30872471 PMCID: PMC6452683 DOI: 10.1073/pnas.1900144116] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Francisella tularensis is the causative agent of tularemia, a category A bioterrorism agent. The lipopolysaccharide (LPS) O antigen (OAg) of F. tularensis has been considered for use in a glycoconjugate vaccine, but conjugate vaccines tested so far have failed to confer protection necessary against aerosolized pulmonary bacterial challenge. When F. tularensis OAg was purified under standard conditions, the antigen had a small molecular size [25 kDa, low molecular weight (LMW)]. Using milder extraction conditions, we found the native OAg had a larger molecular size [80 kDa, high molecular weight (HMW)], and in a mouse model of tularemia, a glycoconjugate vaccine made with the HMW polysaccharide coupled to tetanus toxoid (HMW-TT) conferred better protection against intranasal challenge than a conjugate made with the LMW polysaccharide (LMW-TT). To further investigate the role of OAg size in protection, we created an F. tularensis live vaccine strain (LVS) mutant with a significantly increased OAg size [220 kDa, very high molecular weight (VHMW)] by expressing in F. tularensis a heterologous chain-length regulator gene (wzz) from the related species Francisella novicida Immunization with VHMW-TT provided markedly increased protection over that obtained with TT glycoconjugates made using smaller OAgs. We found that protective antibodies recognize a length-dependent epitope better expressed on HMW and VHMW antigens, which bind with higher affinity to the organism.
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4
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O’Malley KJ, Bowling JL, Stinson E, Cole KS, Mann BJ, Namjoshi P, Hazlett KRO, Barry EM, Reed DS. Aerosol prime-boost vaccination provides strong protection in outbred rabbits against virulent type A Francisella tularensis. PLoS One 2018; 13:e0205928. [PMID: 30346998 PMCID: PMC6197691 DOI: 10.1371/journal.pone.0205928] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/03/2018] [Indexed: 12/15/2022] Open
Abstract
Tularemia, also known as rabbit fever, is a severe zoonotic disease in humans caused by the gram-negative bacterium Francisella tularensis (Ft). While there have been a number of attempts to develop a vaccine for Ft, few candidates have advanced beyond experiments in inbred mice. We report here that a prime-boost strategy with aerosol delivery of recombinant live attenuated candidate Ft S4ΔaroD offers significant protection (83% survival) in an outbred animal model, New Zealand White rabbits, against aerosol challenge with 248 cfu (11 LD50) of virulent type A Ft SCHU S4. Surviving rabbits given two doses of the attenuated strains by aerosol did not exhibit substantial post-challenge fevers, changes in erythrocyte sedimentation rate or in complete blood counts. At a higher challenge dose (3,186 cfu; 139 LD50), protection was still good with 66% of S4ΔaroD-vaccinated rabbits surviving while 50% of S4ΔguaBA vaccinated rabbits also survived challenge. Pre-challenge plasma IgG titers against Ft SCHU S4 corresponded with survival time after challenge. Western blot analysis found that plasma antibody shifted from predominantly targeting Ft O-antigen after the prime vaccination to other antigens after the boost. These results demonstrate the superior protection conferred by a live attenuated derivative of virulent F. tularensis, particularly when given in an aerosol prime-boost regimen.
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Affiliation(s)
- Katherine J. O’Malley
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Jennifer L. Bowling
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Elizabeth Stinson
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Kelly S. Cole
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Barbara J. Mann
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA, United States of America
| | - Prachi Namjoshi
- Department for Immunology & Microbial Diseases, Albany Medical College, Albany, NY, United States of America
| | - Karsten R. O. Hazlett
- Department for Immunology & Microbial Diseases, Albany Medical College, Albany, NY, United States of America
| | - Eileen M. Barry
- Center for Vaccine Development, University of Maryland Baltimore, Baltimore, MD, United States of America
| | - Douglas S. Reed
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA, United States of America
- * E-mail:
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5
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Chen L, Valentine JL, Huang CJ, Endicott CE, Moeller TD, Rasmussen JA, Fletcher JR, Boll JM, Rosenthal JA, Dobruchowska J, Wang Z, Heiss C, Azadi P, Putnam D, Trent MS, Jones BD, DeLisa MP. Outer membrane vesicles displaying engineered glycotopes elicit protective antibodies. Proc Natl Acad Sci U S A 2016; 113:E3609-18. [PMID: 27274048 PMCID: PMC4932928 DOI: 10.1073/pnas.1518311113] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The O-antigen polysaccharide (O-PS) component of lipopolysaccharides on the surface of gram-negative bacteria is both a virulence factor and a B-cell antigen. Antibodies elicited by O-PS often confer protection against infection; therefore, O-PS glycoconjugate vaccines have proven useful against a number of different pathogenic bacteria. However, conventional methods for natural extraction or chemical synthesis of O-PS are technically demanding, inefficient, and expensive. Here, we describe an alternative methodology for producing glycoconjugate vaccines whereby recombinant O-PS biosynthesis is coordinated with vesiculation in laboratory strains of Escherichia coli to yield glycosylated outer membrane vesicles (glycOMVs) decorated with pathogen-mimetic glycotopes. Using this approach, glycOMVs corresponding to eight different pathogenic bacteria were generated. For example, expression of a 17-kb O-PS gene cluster from the highly virulent Francisella tularensis subsp. tularensis (type A) strain Schu S4 in hypervesiculating E. coli cells yielded glycOMVs that displayed F. tularensis O-PS. Immunization of BALB/c mice with glycOMVs elicited significant titers of O-PS-specific serum IgG antibodies as well as vaginal and bronchoalveolar IgA antibodies. Importantly, glycOMVs significantly prolonged survival upon subsequent challenge with F. tularensis Schu S4 and provided complete protection against challenge with two different F. tularensis subsp. holarctica (type B) live vaccine strains, thereby demonstrating the vaccine potential of glycOMVs. Given the ease with which recombinant glycotopes can be expressed on OMVs, the strategy described here could be readily adapted for developing vaccines against many other bacterial pathogens.
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Affiliation(s)
- Linxiao Chen
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853
| | - Jenny L Valentine
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853
| | - Chung-Jr Huang
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853
| | - Christine E Endicott
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853
| | - Tyler D Moeller
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853
| | - Jed A Rasmussen
- Department of Microbiology, University of Iowa, Iowa City, IA 52242
| | | | - Joseph M Boll
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712; Department of Infectious Diseases, The University of Georgia College of Veterinary Medicine, Athens, GA 30602
| | - Joseph A Rosenthal
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Justyna Dobruchowska
- Complex Carbohydrate Research Center, The University of Georgia, Athens, GA 30602
| | - Zhirui Wang
- Complex Carbohydrate Research Center, The University of Georgia, Athens, GA 30602
| | - Christian Heiss
- Complex Carbohydrate Research Center, The University of Georgia, Athens, GA 30602
| | - Parastoo Azadi
- Complex Carbohydrate Research Center, The University of Georgia, Athens, GA 30602
| | - David Putnam
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853; Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - M Stephen Trent
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712; Department of Infectious Diseases, The University of Georgia College of Veterinary Medicine, Athens, GA 30602
| | - Bradley D Jones
- Department of Microbiology, University of Iowa, Iowa City, IA 52242; Genetics Program, University of Iowa, Iowa City, IA 52242
| | - Matthew P DeLisa
- Robert Frederick Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853; Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853;
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6
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Haji-Ghassemi O, Blackler RJ, Martin Young N, Evans SV. Antibody recognition of carbohydrate epitopes†. Glycobiology 2015; 25:920-52. [PMID: 26033938 DOI: 10.1093/glycob/cwv037] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 05/24/2015] [Indexed: 12/14/2022] Open
Abstract
Carbohydrate antigens are valuable as components of vaccines for bacterial infectious agents and human immunodeficiency virus (HIV), and for generating immunotherapeutics against cancer. The crystal structures of anti-carbohydrate antibodies in complex with antigen reveal the key features of antigen recognition and provide information that can guide the design of vaccines, particularly synthetic ones. This review summarizes structural features of anti-carbohydrate antibodies to over 20 antigens, based on six categories of glyco-antigen: (i) the glycan shield of HIV glycoproteins; (ii) tumor epitopes; (iii) glycolipids and blood group A antigen; (iv) internal epitopes of bacterial lipopolysaccharides; (v) terminal epitopes on polysaccharides and oligosaccharides, including a group of antibodies to Kdo-containing Chlamydia epitopes; and (vi) linear homopolysaccharides.
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Affiliation(s)
- Omid Haji-Ghassemi
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 3P6
| | - Ryan J Blackler
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 3P6
| | - N Martin Young
- Human Health Therapeutics, National Research Council of Canada, 100 Sussex Drive, Ottawa, ON, Canada K1A 0R6
| | - Stephen V Evans
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 3P6
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7
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Lu Z, Rynkiewicz MJ, Yang CY, Madico G, Perkins HM, Roche MI, Seaton BA, Sharon J. Functional and structural characterization of Francisella tularensis O-antigen antibodies at the low end of antigen reactivity. Monoclon Antib Immunodiagn Immunother 2015; 33:235-45. [PMID: 25171003 DOI: 10.1089/mab.2014.0022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The O-antigen (OAg) of the Gram-negative bacterium Francisella tularensis (Ft), which is both a capsular polysaccharide and a component of lipopolysaccharide, is comprised of tetrasaccharide repeats and induces antibodies mainly against repeating internal epitopes. We previously reported on several BALB/c mouse monoclonal antibodies (MAbs) that bind to internal Ft OAg epitopes and are protective in mouse models of respiratory tularemia. We now characterize three new internal Ft OAg IgG2a MAbs, N203, N77, and N24, with 10- to 100-fold lower binding potency than previously characterized internal-OAg IgG2a MAbs, despite sharing one or more variable region germline genes with some of them. In a mouse model of respiratory tularemia with the highly virulent Ft type A strain SchuS4, the three new MAbs reduced blood bacterial burden with potencies that mirror their antigen-binding strength; the best binder of the new MAbs, N203, prolonged survival in a dose-dependent manner, but was at least 10-fold less potent than the best previously characterized IgG2a MAb, Ab52. X-ray crystallographic studies of N203 Fab showed a flexible binding site in the form of a partitioned groove, which cannot provide as many contacts to OAg as does the Ab52 binding site. These results reveal structural features of antibodies at the low end of reactivity with multi-repeat microbial carbohydrates and demonstrate that such antibodies still have substantial protective effects against infection.
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Affiliation(s)
- Zhaohua Lu
- 1 Department of Pathology and Laboratory Medicine, Boston University School of Medicine , Boston, Massachusetts
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8
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Lu Z, Rynkiewicz MJ, Madico G, Li S, Yang CY, Perkins HM, Sompuram SR, Kodela V, Liu T, Morris T, Wang D, Roche MI, Seaton BA, Sharon J. B-cell epitopes in GroEL of Francisella tularensis. PLoS One 2014; 9:e99847. [PMID: 24968190 PMCID: PMC4072690 DOI: 10.1371/journal.pone.0099847] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/16/2014] [Indexed: 01/01/2023] Open
Abstract
The chaperonin protein GroEL, also known as heat shock protein 60 (Hsp60), is a prominent antigen in the human and mouse antibody response to the facultative intracellular bacterium Francisella tularensis (Ft), the causative agent of tularemia. In addition to its presumed cytoplasmic location, FtGroEL has been reported to be a potential component of the bacterial surface and to be released from the bacteria. In the current study, 13 IgG2a and one IgG3 mouse monoclonal antibodies (mAbs) specific for FtGroEL were classified into eleven unique groups based on shared VH-VL germline genes, and seven crossblocking profiles revealing at least three non-overlapping epitope areas in competition ELISA. In a mouse model of respiratory tularemia with the highly pathogenic Ft type A strain SchuS4, the Ab64 and N200 IgG2a mAbs, which block each other’s binding to and are sensitive to the same two point mutations in FtGroEL, reduced bacterial burden indicating that they target protective GroEL B-cell epitopes. The Ab64 and N200 epitopes, as well as those of three other mAbs with different crossblocking profiles, Ab53, N3, and N30, were mapped by hydrogen/deuterium exchange–mass spectrometry (DXMS) and visualized on a homology model of FtGroEL. This model was further supported by its experimentally-validated computational docking to the X-ray crystal structures of Ab64 and Ab53 Fabs. The structural analysis and DXMS profiles of the Ab64 and N200 mAbs suggest that their protective effects may be due to induction or stabilization of a conformational change in FtGroEL.
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Affiliation(s)
- Zhaohua Lu
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Michael J. Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Guillermo Madico
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Sheng Li
- Department of Medicine, University of California, San Diego, School of Medicine, San Diego, California, United States of America
| | - Chiou-Ying Yang
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Institute of Molecular Biology, National Chung Hsing University, Taichung, Taiwan
| | - Hillary M. Perkins
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Seshi R. Sompuram
- Medical Discovery Partners, LLC, Boston, Massachusetts, United States of America
| | - Vani Kodela
- Medical Discovery Partners, LLC, Boston, Massachusetts, United States of America
| | - Tong Liu
- Department of Medicine, University of California, San Diego, School of Medicine, San Diego, California, United States of America
| | - Timothy Morris
- Department of Medicine, University of California, San Diego, School of Medicine, San Diego, California, United States of America
| | - Daphne Wang
- Department of Medicine, University of California, San Diego, School of Medicine, San Diego, California, United States of America
| | - Marly I. Roche
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Barbara A. Seaton
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Jacqueline Sharon
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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9
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Sharon J, Rynkiewicz MJ, Lu Z, Yang CY. Discovery of protective B-cell epitopes for development of antimicrobial vaccines and antibody therapeutics. Immunology 2014; 142:1-23. [PMID: 24219801 PMCID: PMC3992043 DOI: 10.1111/imm.12213] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 11/05/2013] [Accepted: 11/08/2013] [Indexed: 01/07/2023] Open
Abstract
Protective antibodies play an essential role in immunity to infection by neutralizing microbes or their toxins and recruiting microbicidal effector functions. Identification of the protective B-cell epitopes, those parts of microbial antigens that contact the variable regions of the protective antibodies, can lead to development of antibody therapeutics, guide vaccine design, enable assessment of protective antibody responses in infected or vaccinated individuals, and uncover or localize pathogenic microbial functions that could be targeted by novel antimicrobials. Monoclonal antibodies are required to link in vivo or in vitro protective effects to specific epitopes and may be obtained from experimental animals or from humans, and their binding can be localized to specific regions of antigens by immunochemical assays. The epitopes are then identified with mapping methods such as X-ray crystallography of antigen-antibody complexes, antibody inhibition of hydrogen-deuterium exchange in the antigen, antibody-induced alteration of the nuclear magnetic resonance spectrum of the antigen, and experimentally validated computational docking of antigen-antibody complexes. The diversity in shape, size and structure of protective B-cell epitopes, and the increasing importance of protective B-cell epitope discovery to development of vaccines and antibody therapeutics are illustrated through examples from different microbe categories, with emphasis on epitopes targeted by broadly neutralizing antibodies to pathogens of high antigenic variation. Examples include the V-shaped Ab52 glycan epitope in the O-antigen of Francisella tularensis, the concave CR6261 peptidic epitope in the haemagglutinin stem of influenza virus H1N1, and the convex/concave PG16 glycopeptidic epitope in the gp120 V1/V2 loop of HIV type 1.
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MESH Headings
- Animals
- Antibodies, Bacterial/immunology
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/therapeutic use
- Antibodies, Viral/immunology
- Antigen-Antibody Reactions
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Viral/chemistry
- Antigens, Viral/immunology
- Bacterial Vaccines/immunology
- Bacterial Vaccines/therapeutic use
- Epitope Mapping
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/immunology
- Humans
- Models, Molecular
- Protein Conformation
- Viral Vaccines/immunology
- Viral Vaccines/therapeutic use
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Affiliation(s)
- Jacqueline Sharon
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of MedicineBoston, MA, USA
| | - Zhaohua Lu
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| | - Chiou-Ying Yang
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
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10
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Antibodies to both terminal and internal B-cell epitopes of Francisella tularensis O-polysaccharide produced by patients with tularemia. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2013; 21:227-33. [PMID: 24351753 DOI: 10.1128/cvi.00626-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Francisella tularensis, the Gram-negative bacterium that causes tularemia, is considered a potential bioterrorism threat due to its low infectivity dose and the high morbidity and mortality from respiratory disease. We previously characterized two mouse monoclonal antibodies (MAbs) specific for the O-polysaccharide (O antigen [OAg]) of F. tularensis lipopolysaccharide (LPS): Ab63, which targets a terminal epitope at the nonreducing end of OAg, and Ab52, which targets a repeating internal OAg epitope. These two MAbs were protective in a mouse model of respiratory tularemia. To determine whether these epitope types are also targeted by humans, we tested the ability of each of 18 blood serum samples from 11 tularemia patients to inhibit the binding of Ab63 or Ab52 to F. tularensis LPS in a competition enzyme-linked immunosorbent assay (ELISA). Although all serum samples had Ab63- and Ab52-inhibitory activities, the ratios of Ab63 to Ab52 inhibitory potencies varied 75-fold. However, the variation was only 2.3-fold for sequential serum samples from the same patient, indicating different distributions of terminal- versus internal-binding antibodies in different individuals. Western blot analysis using class-specific anti-human Ig secondary antibodies showed that both terminal- and internal-binding OAg antibodies were of the IgG, IgM, and IgA isotypes. These results support the use of a mouse model to discover protective B-cell epitopes for tularemia vaccines or prophylactic/therapeutic antibodies, and they present a general strategy for interrogating the antibody responses of patients and vaccinees to microbial carbohydrate epitopes that have been characterized in experimental animals.
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Lu Z, Rynkiewicz MJ, Yang CY, Madico G, Perkins HM, Wang Q, Costello CE, Zaia J, Seaton BA, Sharon J. The binding sites of monoclonal antibodies to the non-reducing end of Francisella tularensis O-antigen accommodate mainly the terminal saccharide. Immunology 2013; 140:374-89. [PMID: 23844703 DOI: 10.1111/imm.12150] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/19/2013] [Accepted: 07/05/2013] [Indexed: 11/27/2022] Open
Abstract
We have previously described two types of protective B-cell epitopes in the O-antigen (OAg) of the Gram-negative bacterium Francisella tularensis: repeating internal epitopes targeted by the vast majority of anti-OAg monoclonal antibodies (mAbs), and a non-overlapping epitope at the non-reducing end targeted by the previously unique IgG2a mAb FB11. We have now generated and characterized three mAbs specific for the non-reducing end of F. tularensis OAg, partially encoded by the same variable region germline genes, indicating that they target the same epitope. Like FB11, the new mAbs, Ab63 (IgG3), N213 (IgG3) and N62 (IgG2b), had higher antigen-binding bivalent avidity than internally binding anti-OAg mAbs, and an oligosaccharide containing a single OAg repeat was sufficient for optimal inhibition of their antigen-binding. The X-ray crystal structure of N62 Fab showed that the antigen-binding site is lined mainly by aromatic amino acids that form a small cavity, which can accommodate no more than one and a third sugar residues, indicating that N62 binds mainly to the terminal Qui4NFm residue at the nonreducing end of OAg. In efficacy studies with mice infected intranasally with the highly virulent F. tularensis strain SchuS4, N62, N213 and Ab63 prolonged survival and reduced blood bacterial burden. These results yield insights into how antibodies to non-reducing ends of microbial polysaccharides can contribute to immune protection despite the smaller size of their target epitopes compared with antibodies to internal polysaccharide regions.
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Affiliation(s)
- Zhaohua Lu
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
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Okan NA, Kasper DL. The atypical lipopolysaccharide of Francisella. Carbohydr Res 2013; 378:79-83. [PMID: 23916469 DOI: 10.1016/j.carres.2013.06.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/15/2013] [Accepted: 06/20/2013] [Indexed: 01/17/2023]
Abstract
Bacterial lipopolysaccharides (LPSs) are ubiquitous molecules that are prominent components of the outer membranes of most gram-negative bacteria. Genetic and structural characterizations of Francisella LPS have revealed substantial differences when compared to more commonly studied LPSs of the Enterobacteriaceae. This review discusses both the general characteristics and the unusual features of Francisella LPS.
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Affiliation(s)
- Nihal A Okan
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, United States
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Crane DD, Griffin AJ, Wehrly TD, Bosio CM. B1a cells enhance susceptibility to infection with virulent Francisella tularensis via modulation of NK/NKT cell responses. THE JOURNAL OF IMMUNOLOGY 2013; 190:2756-66. [PMID: 23378429 DOI: 10.4049/jimmunol.1202697] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
B1a cells are an important source of natural Abs, Abs directed against T-independent Ags, and are a primary source of IL-10. Bruton's tyrosine kinase (btk) is a cytoplasmic kinase that is essential for mediating signals from the BCR and is critical for development of B1a cells. Consequentially, animals lacking btk have few B1a cells, minimal Ab responses, and can preferentially generate Th1-type immune responses following infection. B1a cells have been shown to aid in protection against infection with attenuated Francisella tularensis, but their role in infection mediated by fully virulent F. tularensis is not known. Therefore, we used mice with defective btk (CBA/CaHN-Btk(XID)/J [XID mice]) to determine the contribution of B1a cells in defense against the virulent F. tularensis ssp. tularensis strain SchuS4. Surprisingly, XID mice displayed increased resistance to pulmonary infection with F. tularensis. Specifically, XID mice had enhanced clearance of bacteria from the lung and spleen and significantly greater survival of infection compared with wild-type controls. We revealed that resistance to infection in XID mice was associated with decreased numbers of IL-10-producing B1a cells and concomitant increased numbers of IL-12-producing macrophages and IFN-γ-producing NK/NKT cells. Adoptive transfer of wild-type B1a cells into XID mice reversed the control of bacterial replication. Similarly, depletion of NK/NKT cells also increased bacterial burdens in XID mice. Together, our data suggest B cell-NK/NKT cell cross-talk is a critical pivot controlling survival of infection with virulent F. tularensis.
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Affiliation(s)
- Deborah D Crane
- Immunity to Pulmonary Pathogens Section, Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases/National Institutes of Health, Hamilton, MT 59840, USA
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Rynkiewicz MJ, Lu Z, Hui JH, Sharon J, Seaton BA. Structural analysis of a protective epitope of the Francisella tularensis O-polysaccharide. Biochemistry 2012; 51:5684-94. [PMID: 22747335 DOI: 10.1021/bi201711m] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Francisella tularensis (Ft), the Gram-negative facultative intracellular bacterium that causes tularemia, is considered a biothreat because of its high infectivity and the high mortality rate of respiratory disease. The Ft lipopolysaccharide (Ft LPS) is thought to be a main protective antigen in mice and humans, and we have previously demonstrated the protective effect of the Ft LPS-specific monoclonal antibody Ab52 in a mouse model of respiratory tularemia. Immunochemical characterization has shown that the epitope recognized by Ab52 is contained within two internal repeat units of the O-polysaccharide [O-antigen (OAg)] of Ft LPS. To further localize the Ab52 epitope and understand the molecular interactions between the antibody and the saccharide, we determined the X-ray crystal structure of the Fab fragment of Ab52 and derived an antibody-antigen complex using molecular docking. The docked complex, refined through energy minimization, reveals an antigen binding site in the shape of a large canyon with a central pocket that accommodates a V-shaped epitope consisting of six sugar residues, α-D-GalpNAcAN(1→4)-α-D-GalpNAcAN(1→3)-β-D-QuipNAc(1→2)-β-D-Quip4NFm(1→4)-α-D-GalpNAcAN(1→4)-α-D-GalpNAcAN. These results inform the development of vaccines and immunotherapeutic/immunoprophylactic antibodies against Ft by suggesting a desired topology for binding of the antibody to internal epitopes of Ft LPS. This is the first report of an X-ray crystal structure of a monoclonal antibody that targets a protective Ft B cell epitope.
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Affiliation(s)
- Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
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