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Li Q, Ma X, Shen Y, Dai J, Nian X, Shang X, Chen J, Wubshet AK, Zhang J, Zheng H. Chimeric Porcine Parvovirus VP2 Virus-like Particles with Epitopes of South African Serotype 2 Foot-and-Mouth Disease Virus Elicits Specific Humoral and Cellular Responses in Mice. Viruses 2024; 16:621. [PMID: 38675963 PMCID: PMC11054767 DOI: 10.3390/v16040621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 03/30/2024] [Accepted: 04/11/2024] [Indexed: 04/28/2024] Open
Abstract
Southern Africa Territories 2 (SAT2) foot-and-mouth disease (FMD) has crossed long-standing regional boundaries in recent years and entered the Middle East. However, the existing vaccines offer poor cross-protection against the circulating strains in the field. Therefore, there is an urgent need for an alternative design approach for vaccines in anticipation of a pandemic of SAT2 Foot-and-mouth disease virus (FMDV). The porcine parvovirus (PPV) VP2 protein can embed exogenous epitopes into the four loops on its surface, assemble into virus-like particles (VLPs), and induce antibodies and cytokines to PPV and the exogenous epitope. In this study, chimeric porcine parvovirus VP2 VLPs (chimeric PPV-SAT2-VLPs) expressing the T-and/or B-cell epitopes of the structural protein VP1 of FMDV SAT2 were produced using the recombinant pFastBac™ Dual vector of baculoviruses in Sf9 and HF cells We used the Bac-to-Bac system to construct the recombinant baculoviruses. The VP2-VLP--SAT2 chimeras displayed chimeric T-cell epitope (amino acids 21-40 of VP1) and/or the B-cell epitope (amino acids 135-174) of SAT FMDV VP1 by substitution of the corresponding regions at the N terminus (amino acids 2-23) and/or loop 2 and/or loop 4 of the PPV VP2 protein, respectively. In mice, the chimeric PPV-SAT2-VLPs induced specific antibodies against PPV and the VP1 protein of SAT2 FMDV. The VP2-VLP-SAT2 chimeras induced specific antibodies to PPV and the VP1 protein specific epitopes of FMDV SAT2. In this study, as a proof-of-concept, successfully generated chimeric PPV-VP2 VLPs expressing epitopes of the structural protein VP1 of FMDV SAT2 that has a potential to prevent FMDV SAT2 and PPV infection in pigs.
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MESH Headings
- Animals
- Foot-and-Mouth Disease Virus/immunology
- Foot-and-Mouth Disease Virus/genetics
- Mice
- Foot-and-Mouth Disease/immunology
- Foot-and-Mouth Disease/prevention & control
- Foot-and-Mouth Disease/virology
- Capsid Proteins/immunology
- Capsid Proteins/genetics
- Parvovirus, Porcine/immunology
- Parvovirus, Porcine/genetics
- Antibodies, Viral/immunology
- Antibodies, Viral/blood
- Viral Vaccines/immunology
- Viral Vaccines/genetics
- Vaccines, Virus-Like Particle/immunology
- Vaccines, Virus-Like Particle/genetics
- Swine
- Immunity, Humoral
- Immunity, Cellular
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/genetics
- Epitopes, B-Lymphocyte/immunology
- Epitopes, B-Lymphocyte/genetics
- Serogroup
- Mice, Inbred BALB C
- Female
- Epitopes/immunology
- Epitopes/genetics
- Sf9 Cells
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/blood
- Antigens, Viral
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Affiliation(s)
- Qian Li
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
- College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China
| | - Xusheng Ma
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
| | - Yaner Shen
- China Agricultural Vet Biologyand Technology Co., Ltd., Lanzhou 730046, China;
| | - Junfei Dai
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
| | - Xiaofeng Nian
- China-Malaysia National Joint Laboratory, Biomedical Research Center, Life Science and Engineering College, Northwest Minzu University, Lanzhou 730030, China;
| | - Xiaofen Shang
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
| | - Jiao Chen
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
| | - Ashenafi Kiros Wubshet
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
| | - Jie Zhang
- Hebei Key Laboratory of Preventive Veterinary Medicine, College of Animal Science and Technology, Hebei Normal University of Science and Technology, Qinhuangdao 066004, China
| | - Haixue Zheng
- State Key Laboratory for Animal Disease Control and Prevention, Lanzhou Veterinary Research Institute, College of Veterinary Medicine, Lanzhou University, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China; (Q.L.); (X.M.); (J.D.); (X.S.); (J.C.); (A.K.W.)
- Gansu Province Research Center for Basic Disciplines of Pathogen Biology, Lanzhou 730046, China
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Fehrsen J, Wemmer S, van Wyngaardt W. Construction of Chicken and Ostrich Antibody Libraries. Methods Mol Biol 2023; 2702:77-92. [PMID: 37679616 DOI: 10.1007/978-1-0716-3381-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Recombinant antibody libraries based on chicken immunoglobulin genes are potentially valuable sources of phage-displayed scFvs for use in veterinary diagnostics and research. To add diversity to the scFv repertoire, we expanded the library to include genes from the ostrich, indigenous to southern Africa. The libraries described in this chapter are based on the chicken and ostrich variable heavy and light chain immunoglobulin genes joined by a short flexible linker cloned in the phagemid vector pHEN1. The resulting phagemids produce either scFvs displayed on the surface of the fusion phage subsequent to co-infection with helper phage or soluble scFvs following IPTG induction. This chapter provides detailed and proven methods for the construction of such libraries.
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Affiliation(s)
- Jeanni Fehrsen
- ARC-Onderstepoort Veterinary Research, Pretoria, South Africa.
| | - Susan Wemmer
- ARC-Onderstepoort Veterinary Research, Pretoria, South Africa
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Chitray M, Opperman PA, Rotherham L, Fehrsen J, van Wyngaardt W, Frischmuth J, Rieder E, Maree FF. Diagnostic and Epitope Mapping Potential of Single-Chain Antibody Fragments Against Foot-and-Mouth Disease Virus Serotypes A, SAT1, and SAT3. Front Vet Sci 2020; 7:475. [PMID: 32851044 PMCID: PMC7432252 DOI: 10.3389/fvets.2020.00475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 06/25/2020] [Indexed: 11/13/2022] Open
Abstract
Foot-and-mouth disease (FMD) affects cloven-hoofed domestic and wildlife animals and an outbreak can cause severe losses in milk production, reduction in meat production and death amongst young animals. Several parts of Asia, most of Africa, and the Middle East remain endemic, thus emphasis on improved FMD vaccines, diagnostic assays, and control measures are key research areas. FMD virus (FMDV) populations are quasispecies, which pose serious implications in vaccine design and efficacy where an effective vaccine should include multiple independent neutralizing epitopes to elicit an adequate immune response. Further investigation of the residues that comprise the antigenic determinants of the virus will allow the identification of mutations in outbreak strains that potentially lessen the efficacy of a vaccine. Additionally, of utmost importance in endemic regions, is the accurate diagnosis of FMDV infection for the control and eradication of the disease. To this end, a phage display library was explored to identify FMDV epitopes for recombinant vaccines and for the generation of reagents for improved diagnostic FMD enzyme-linked immunosorbent assays (ELISAs). A naïve semi-synthetic chicken single chain variable fragment (scFv) phage display library i.e., the Nkuku ® library was used for bio-panning against FMD Southern-African Territories (SAT) 1, SAT3, and serotype A viruses. Biopanning yielded one unique scFv against SAT1, two for SAT3, and nine for A22. SAT1 and SAT3 specific scFvs were exploited as capturing and detecting reagents to develop an improved diagnostic ELISA for FMDV. The SAT1 soluble scFv showed potential as a detecting reagent in the liquid phase blocking ELISA (LPBE) as it reacted specifically with a panel of SAT1 viruses, albeit with different ELISA absorbance signals. The SAT1svFv1 had little or no change on its paratope when coated on polystyrene plates whilst the SAT3scFv's paratope may have changed. SAT1 and SAT3 soluble scFvs did not neutralize the SAT1 and SAT3 viruses; however, three of the nine A22 binders i.e., A22scFv1, A22scFv2, and A22scFv8 were able to neutralize A22 virus. Following the generation of virus escape mutants through successive virus passage under scFv pressure, FMDV epitopes were postulated i.e., RGD+3 and +4 positions respectively, proving the epitope mapping potential of scFvs.
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Affiliation(s)
- Melanie Chitray
- Agricultural Research Council, Onderstepoort Veterinary Research, Vaccines and Diagnostic Development, Onderstepoort, Pretoria, South Africa.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Pamela Anne Opperman
- Agricultural Research Council, Onderstepoort Veterinary Research, Vaccines and Diagnostic Development, Onderstepoort, Pretoria, South Africa.,Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Lia Rotherham
- Agricultural Research Council, Onderstepoort Veterinary Research, Vaccines and Diagnostic Development, Onderstepoort, Pretoria, South Africa
| | - Jeanni Fehrsen
- Agricultural Research Council, Onderstepoort Veterinary Research, Vaccines and Diagnostic Development, Onderstepoort, Pretoria, South Africa.,Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Wouter van Wyngaardt
- Agricultural Research Council, Onderstepoort Veterinary Research, Vaccines and Diagnostic Development, Onderstepoort, Pretoria, South Africa
| | - Janine Frischmuth
- Biotechnology Division, National Bioproducts Institute, Pinetown, South Africa
| | - Elizabeth Rieder
- Plum Island Animal Disease Centre, U.S. Department of Agriculture, Agricultural Research Service, Greenport, NY, United States
| | - Francois Frederick Maree
- Agricultural Research Council, Onderstepoort Veterinary Research, Vaccines and Diagnostic Development, Onderstepoort, Pretoria, South Africa.,Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, South Africa
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Ramulongo TD, Maree FF, Scott K, Opperman P, Mutowembwa P, Theron J. Pathogenesis, biophysical stability and phenotypic variance of SAT2 foot-and-mouth disease virus. Vet Microbiol 2020; 243:108614. [PMID: 32273026 DOI: 10.1016/j.vetmic.2020.108614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/14/2020] [Accepted: 02/16/2020] [Indexed: 11/27/2022]
Abstract
Foot-and-mouth disease (FMD) is a highly contagious vesicular disease of cloven-hoofed animals, which severely decreases livestock productivity. FMD virus (FMDV), the causative agent, initiates infection by interaction with integrin cellular receptors on pharyngeal epithelium cells, causing clinical signs one to four days after transmission to a susceptible host. However, some Southern African Territories (SAT) viruses have been reported to cause mild or subclinical infections that may go undiagnosed in field conditions and are likely to be more common than previously expected. The studies presented here demonstrate that not all SAT2 viruses are equally virulent in cattle. The two SAT2 viruses, ZIM/5/83 and ZIM/7/83, were both highly attenuated in cattle, as evidenced by the mild clinical signs observed after needle challenge, while two incongruent SAT2 viruses showed significantly different clinical signs in challenged cattle. We then explored the ability of the SAT2 viruses to infect different cell types with defined receptors that are utilised by FMDV and found differences in their ability to lyse cells in culture and to compete in a controlled cell culture environment. The population sequence variation between ZIM/5/83 and ZIM/7/83 revealed multiple sites of single nucleotide variants of low frequency between the predominant virus populations, as could be expected from the genome of an RNA virus. An assessment of the biophysical stability of SAT2 virions during acidification indicated that the SAT2 virus EGY/09/12 was more resilient to acidification than the ZIM/5/83 and ZIM/7/83 viruses; however, whether this difference relates to differences in virulence in vivo is unclear. This study is a consolidated view of the key findings of SAT2 viruses studied over a 14-year period involving many different experiments.
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Affiliation(s)
- Tovhowani D Ramulongo
- Transboundary Animal Diseases, Vaccine and Diagnostic Development Programme, Onderstepoort Veterinary Research Institute, Agricultural Research Council, Onderstepoort, Pretoria, 0110, South Africa; Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0002, South Africa
| | - Francois F Maree
- Transboundary Animal Diseases, Vaccine and Diagnostic Development Programme, Onderstepoort Veterinary Research Institute, Agricultural Research Council, Onderstepoort, Pretoria, 0110, South Africa; Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, University of Pretoria, Pretoria, 0002, South Africa.
| | - Katherine Scott
- Transboundary Animal Diseases, Vaccine and Diagnostic Development Programme, Onderstepoort Veterinary Research Institute, Agricultural Research Council, Onderstepoort, Pretoria, 0110, South Africa
| | - Pamela Opperman
- Transboundary Animal Diseases, Vaccine and Diagnostic Development Programme, Onderstepoort Veterinary Research Institute, Agricultural Research Council, Onderstepoort, Pretoria, 0110, South Africa; Department Animal Production Studies, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, 0110, South Africa
| | - Paidamwoyo Mutowembwa
- Transboundary Animal Diseases, Vaccine Production Programme, Onderstepoort Veterinary Research Institute, Agricultural Research Council, Onderstepoort, Pretoria, 0110, South Africa
| | - Jacques Theron
- Department Animal Production Studies, Faculty of Veterinary Sciences, University of Pretoria, Pretoria, 0110, South Africa
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Abstract
Recombinant antibody libraries based on chicken immunoglobulin genes are potentially valuable sources of phage displayed scFvs for use in veterinary diagnostics and research. The libraries described in this chapter are based on chicken variable heavy and light chain immunoglobulin genes joined by a short flexible linker cloned in the phagemid vector pHEN1. The resulting phagemids produce either scFvs displayed on the surface of the fusion phage subsequent to co-infection with helper phage, or soluble scFvs following IPTG induction. This chapter provides detailed and proven methods for the construction of such libraries.
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Affiliation(s)
- Jeanni Fehrsen
- Immunology Division, New Generation Vaccines Programme, ARC-Onderstepoort Veterinary Research, Onderstepoort, Pretoria, 0110, South Africa.
| | - Susan Wemmer
- Immunology Division, New Generation Vaccines Programme, ARC-Onderstepoort Veterinary Research, Onderstepoort, Pretoria, 0110, South Africa
| | - Wouter van Wyngaardt
- Immunology Division, New Generation Vaccines Programme, ARC-Onderstepoort Veterinary Research, Onderstepoort, Pretoria, 0110, South Africa
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6
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Evaluation of immune responses of stabilised SAT2 antigens of foot-and-mouth disease in cattle. Vaccine 2017; 35:5426-5433. [DOI: 10.1016/j.vaccine.2017.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/01/2016] [Accepted: 02/01/2017] [Indexed: 11/20/2022]
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Maree FF, Kasanga CJ, Scott KA, Opperman PA, Melanie C, Sangula AK, Raphael S, Yona S, Wambura PN, King DP, Paton DJ, Rweyemamu MM. Challenges and prospects for the control of foot-and-mouth disease: an African perspective. VETERINARY MEDICINE-RESEARCH AND REPORTS 2014; 5:119-138. [PMID: 32670853 PMCID: PMC7337166 DOI: 10.2147/vmrr.s62607] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 04/23/2014] [Indexed: 11/23/2022]
Abstract
The epidemiology of foot-and-mouth disease (FMD) in Africa is unique in the sense that six of the seven serotypes of FMD viruses (Southern African Territories [SAT] 1, SAT2, SAT3, A, O, and C), with the exception of Asia-1, have occurred in the last decade. Due to underreporting of FMD, the current strains circulating throughout sub-Saharan Africa are in many cases unknown. For SAT1, SAT2, and serotype A viruses, the genetic diversity is reflected in antigenic variation, and indications are that vaccine strains may be needed for each topotype. This has serious implications for control using vaccines and for choice of strains to include in regional antigen banks. The epidemiology is further complicated by the fact that SAT1, SAT2, and SAT3 viruses are maintained and spread by wildlife, persistently infecting African buffalo in particular. Although the precise mechanism of transmission of FMD from buffalo to cattle is not well understood, it is facilitated by direct contact between these two species. Once cattle are infected they may maintain SAT infections without the further involvement of buffalo. No single strategy for control of FMD in Africa is applicable. Decision on the most effective regional control strategy should focus on an ecosystem approach, identification of primary endemic areas, animal husbandry practices, climate, and animal movement. Within each ecosystem, human behavior could be integrated in disease control planning. Different regions in sub-Saharan Africa are at different developmental stages and are thus facing unique challenges and priorities in terms of veterinary disease control. Many science-based options targeting improved vaccinology, diagnostics, and other control measures have been described. This review therefore aims to emphasize, on one hand, the progress that has been achieved in the development of new technologies, including research towards improved tailored vaccines, appropriate vaccine strain selection, vaccine potency, and diagnostics, and how it relates to the conditions in Africa. On the other hand, we focus on the unique epidemiological, ecological, livestock farming and marketing, socioeconomic, and governance issues that constrain effective FMD control. Any such new technologies should have the availability of safe livestock products for trade as the ultimate goal.
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Affiliation(s)
- Francois F Maree
- Transboundary Animal Diseases Programme, Onderstepoort Veterinary Institute, Agricultural Research Council, Onderstepoort, Pretoria, South Africa.,Department of Microbiology and Plant Pathology, Faculty of Agricultural and Natural Sciences, University of Pretoria, Pretoria, South Africa
| | - Christopher J Kasanga
- Southern African Centre for Infectious Diseases Surveillance, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Katherine A Scott
- Transboundary Animal Diseases Programme, Onderstepoort Veterinary Institute, Agricultural Research Council, Onderstepoort, Pretoria, South Africa
| | - Pamela A Opperman
- Transboundary Animal Diseases Programme, Onderstepoort Veterinary Institute, Agricultural Research Council, Onderstepoort, Pretoria, South Africa.,Department of Microbiology and Plant Pathology, Faculty of Agricultural and Natural Sciences, University of Pretoria, Pretoria, South Africa
| | - Chitray Melanie
- Transboundary Animal Diseases Programme, Onderstepoort Veterinary Institute, Agricultural Research Council, Onderstepoort, Pretoria, South Africa.,Department of Microbiology and Plant Pathology, Faculty of Agricultural and Natural Sciences, University of Pretoria, Pretoria, South Africa
| | | | - Sallu Raphael
- Southern African Centre for Infectious Diseases Surveillance, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Sinkala Yona
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka, Zambia
| | - Philemon N Wambura
- Southern African Centre for Infectious Diseases Surveillance, Sokoine University of Agriculture, Morogoro, Tanzania
| | | | | | - Mark M Rweyemamu
- Southern African Centre for Infectious Diseases Surveillance, Sokoine University of Agriculture, Morogoro, Tanzania
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Determining the epitope dominance on the capsid of a serotype SAT2 foot-and-mouth disease virus by mutational analyses. J Virol 2014; 88:8307-18. [PMID: 24829347 DOI: 10.1128/jvi.00470-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Monoclonal-antibody (MAb)-resistant mutants were used to map antigenic sites on foot-and-mouth disease virus (FMDV), which resulted in the identification of neutralizing epitopes in the flexible βG-βH loop in VP1. For FMDV SAT2 viruses, studies have shown that at least two antigenic sites exist. By use of an infectious SAT2 cDNA clone, 10 structurally exposed and highly variable loops were identified as putative antigenic sites on the VP1, VP2, and VP3 capsid proteins of SAT2/Zimbabwe (ZIM)/7/83 (topotype II) and replaced with the corresponding regions of SAT2/Kruger National Park (KNP)/19/89 (topotype I). Virus neutralization assays using convalescent-phase antisera raised against the parental virus, SAT2/ZIM/7/83, indicated that the mutant virus containing the TQQS-to-ETPV mutation in the N-terminal part of the βG-βH loop of VP1 showed not only a significant increase in the neutralization titer but also an increase in the index of avidity to the convalescent-phase antisera. Furthermore, antigenic profiling of the epitope-replaced and parental viruses with nonneutralizing SAT2-specific MAbs led to the identification of two nonneutralizing antigenic regions. Both regions were mapped to incorporate residues 71 to 72 of VP2 as the major contact point. The binding footprint of one of the antigenic regions encompasses residues 71 to 72 and 133 to 134 of VP2 and residues 48 to 50 of VP1, and the second antigenic region encompasses residues 71 to 72 and 133 to 134 of VP2 and residues 84 to 86 and 109 to 11 of VP1. This is the first time that antigenic regions encompassing residues 71 to 72 of VP2 have been identified on the capsid of a SAT2 FMDV. IMPORTANCE Monoclonal-antibody-resistant mutants have traditionally been used to map antigenic sites on foot-and-mouth disease virus (FMDV). However, for SAT2-type viruses, which are responsible for most of the FMD outbreaks in Africa and are the most varied of all seven serotypes, only two antigenic sites have been identified. We have followed a unique approach using an infectious SAT2 cDNA genome-length clone. Ten structurally surface-exposed, highly varied loops were identified as putative antigenic sites on the VP1, VP2, and VP3 capsid proteins of the SAT2/ZIM/7/83 virus. These regions were replaced with the corresponding regions of an antigenically disparate virus, SAT2/KNP/19/89. Antigenic profiling of the epitope-replaced and parental viruses with SAT2-specific MAbs led to the identification of two unique antibody-binding footprints on the SAT2 capsid. In this report, evidence for the structural engineering of antigenic sites of a SAT2 capsid to broaden cross-reactivity with antisera is provided.
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