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Antibody Response to Rotavirus C Pre-Farrow Natural Planned Exposure to Gilts and Their Piglets. Viruses 2022; 14:v14102250. [PMID: 36298806 PMCID: PMC9610825 DOI: 10.3390/v14102250] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022] Open
Abstract
A longitudinal study was conducted to investigate the dynamics of genotype-specific (G6 and P[5]) antibody response to different doses (3, 2 and 1) of rotavirus C (RVC) natural planned exposure (NPE) in gilt serum, colostrum/milk and piglet serum, and compare with antibody response to rotavirus A NPE (RVA genotypes G4, G5, P[7] and P[23]). G6 and P[5] antigens of RVC were expressed in mammalian and bacterial cells, and used to develop individual indirect ELISAs. For both antigens, group 1 with 3 doses of NPE resulted in significantly higher IgG and IgA levels in colostrum compared to other groups. In piglet serum, group 1 P[5] IgG levels were significantly higher than other study groups at day 0 and 7. Piglet serum had higher IgA levels for group 1 piglets compared to other groups for both antigens. A comparison of colostrum antibody levels to rotavirus A (RVA) and RVC revealed that colostrum RVC IgG and IgA titers were lower than RVA titers irrespective of the G and P-type. Next generation sequencing (NGS) detected same RVC genotypes (G6 and P[5]) circulating in the piglet population under the window of lactogenic immunity. We conclude that the low RVC load in NPE material (real-time PCR Ct-values 32.55, 29.32 and 30.30) failed to induce sufficient maternal immunity in gilts (low colostrum RVC antibody levels) and passively prevent piglets from natural RVC infection in the farrowing room. To the best of our knowledge, this is the first study comparing differences in antibody response to porcine RVA and RVC in a commercial setting.
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2
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Kumar D, Shepherd FK, Springer NL, Mwangi W, Marthaler DG. Rotavirus Infection in Swine: Genotypic Diversity, Immune Responses, and Role of Gut Microbiome in Rotavirus Immunity. Pathogens 2022; 11:pathogens11101078. [PMID: 36297136 PMCID: PMC9607047 DOI: 10.3390/pathogens11101078] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/13/2022] [Accepted: 09/17/2022] [Indexed: 11/16/2022] Open
Abstract
Rotaviruses (RVs) are endemic in swine populations, and all swine herds certainly have a history of RV infection and circulation. Rotavirus A (RVA) and C (RVC) are the most common among all RV species reported in swine. RVA was considered most prevalent and pathogenic in swine; however, RVC has been emerging as a significant cause of enteritis in newborn piglets. RV eradication from swine herds is not practically achievable, hence producers’ mainly focus on minimizing the production impact of RV infections by reducing mortality and diarrhea. Since no intra-uterine passage of immunoglobulins occur in swine during gestation, newborn piglets are highly susceptible to RV infection at birth. Boosting lactogenic immunity in gilts by using vaccines and natural planned exposure (NPE) is currently the only way to prevent RV infections in piglets. RVs are highly diverse and multiple RV species have been reported from swine, which also contributes to the difficulties in preventing RV diarrhea in swine herds. Human RV-gut microbiome studies support a link between microbiome composition and oral RV immunogenicity. Such information is completely lacking for RVs in swine. It is not known how RV infection affects the functionality or structure of gut microbiome in swine. In this review, we provide a detailed overview of genotypic diversity of swine RVs, host-ranges, innate and adaptive immune responses to RVs, homotypic and heterotypic immunity to RVs, current methods used for RV management in swine herds, role of maternal immunity in piglet protection, and prospects of investigating swine gut microbiota in providing immunity against rotaviruses.
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Affiliation(s)
- Deepak Kumar
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
- Correspondence: (D.K.); (W.M.); (D.G.M.); Tel.: +1-804-503-1241 (D.K.)
| | - Frances K Shepherd
- Department of Microbiology and Immunology, University of Minnesota, Minneapolis, MN 55108, USA
| | - Nora L. Springer
- Clinical Pathology, Biomedical and Diagnostic Sciences, College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA
| | - Waithaka Mwangi
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA
- Correspondence: (D.K.); (W.M.); (D.G.M.); Tel.: +1-804-503-1241 (D.K.)
| | - Douglas G. Marthaler
- Indical Inc., 1317 Edgewater Dr #3722, Orlando, FL 32804, USA
- Correspondence: (D.K.); (W.M.); (D.G.M.); Tel.: +1-804-503-1241 (D.K.)
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3
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Zeng Y, Song F, Luo G, Yang H, Li C, Liu W, Li T, Zhang S, Wang Y, Huang C, Ge S, Zhang J, Xia N. Generation and characterization of mouse monoclonal antibodies against the VP4 protein of group A human rotaviruses. Antiviral Res 2022; 207:105407. [PMID: 36152816 DOI: 10.1016/j.antiviral.2022.105407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 12/01/2022]
Abstract
Human rotaviruses (RVs) are the leading cause of severe diarrhea in infants and young children worldwide. Among the structural proteins, as a spike protein, rotavirus VP4 plays a key role in both viral attachment and penetration. Currently, studies on monoclonal antibodies (mAbs) against VP4 are limited. In this study, mice were immunized with truncated VP4* to produce murine mAbs. In total, 50 mAbs were produced and characterized. Twenty-four mAbs were genotype-specific and 20 mAbs recognized the common VP4 epitopes shared by P[8], P[4], and P[6] viruses. Thirty-five of the 50 mAbs were neutralizing mAbs, among which nine mAbs could neutralize all three P-genotype RVs, and 10 neutralizing mAbs exhibited conformational sensitivity. Ten mAbs recognized dominant neutralizing epitopes, including the broadly neutralizing mAb 9C4 recognized conformational epitope. Further investigation shows that S376 and S464 are key amino acids for 9C4 binding, however, the exact binding sites of 9C4 remain to be fully defined. Overall, this panel of mAbs has demonstrated utility as immunodiagnostic and research reagents, and could potentially serve as crucial tools for exploring the neutralizing mechanisms and quality control of VP4* protein-based RV subunit vaccines. Further evaluation of cross-neutralizing mAbs could not only improve the understanding of the heterotypic protection conferred by RV vaccines, but also facilitate the development of broadly protective RV vaccines.
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Affiliation(s)
- Yuanjun Zeng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Feibo Song
- The Research Unit of Frontier Technology of Structural Vaccinology of Chinese Academy of Medical Sciences, People's Republic of China
| | - Guoxing Luo
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Han Yang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Cao Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Wei Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Tingdong Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China.
| | - Shiyin Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Yingbin Wang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China.
| | - Chenghao Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Shengxiang Ge
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China.
| | - Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, People's Republic of China; The Research Unit of Frontier Technology of Structural Vaccinology of Chinese Academy of Medical Sciences, People's Republic of China
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4
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Rotavirus Spike Protein VP4 Mediates Viroplasm Assembly by Association to Actin Filaments. J Virol 2022; 96:e0107422. [PMID: 35938869 PMCID: PMC9472636 DOI: 10.1128/jvi.01074-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Rotavirus (RV) viroplasms are cytosolic inclusions where both virus genome replication and primary steps of virus progeny assembly take place. A stabilized microtubule cytoskeleton and lipid droplets are required for the viroplasm formation, which involves several virus proteins. The viral spike protein VP4 has not previously been shown to have a direct role in viroplasm formation. However, it is involved with virus-cell attachment, endocytic internalization, and virion morphogenesis. Moreover, VP4 interacts with actin cytoskeleton components, mainly in processes involving virus entrance and egress, and thereby may have an indirect role in viroplasm formation. In this study, we used reverse genetics to construct a recombinant RV, rRV/VP4-BAP, that contains a biotin acceptor peptide (BAP) in the K145-G150 loop of the VP4 lectin domain, permitting live monitoring. The recombinant virus was replication competent but showed a reduced fitness. We demonstrate that rRV/VP4-BAP infection, as opposed to rRV/wt infection, did not lead to a reorganized actin cytoskeleton as viroplasms formed were insensitive to drugs that depolymerize actin and inhibit myosin. Moreover, wild-type (wt) VP4, but not VP4-BAP, appeared to associate with actin filaments. Similarly, VP4 in coexpression with NSP5 and NSP2 induced a significant increase in the number of viroplasm-like structures. Interestingly, a small peptide mimicking loop K145-G150 rescued the phenotype of rRV/VP4-BAP by increasing its ability to form viroplasms and hence improve virus progeny formation. Collectively, these results provide a direct link between VP4 and the actin cytoskeleton to catalyze viroplasm assembly. IMPORTANCE The spike protein VP4 participates in diverse steps of the rotavirus (RV) life cycle, including virus-cell attachment, internalization, modulation of endocytosis, virion morphogenesis, and virus egress. Using reverse genetics, we constructed for the first time a recombinant RV, rRV/VP4-BAP, harboring a heterologous peptide in the lectin domain (loop K145-G150) of VP4. The rRV/VP4-BAP was replication competent but with reduced fitness due to a defect in the ability to reorganize the actin cytoskeleton, which affected the efficiency of viroplasm assembly. This defect was rescued by adding a permeable small-peptide mimicking the wild-type VP4 loop K145-G150. In addition to revealing a new role of VP4, our findings suggest that rRV harboring an engineered VP4 could be used as a new dual vaccination platform providing immunity against RV and additional heterologous antigens.
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5
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The Guanine Nucleotide Exchange Factor GBF1 Participates in Rotavirus Replication. J Virol 2019; 93:JVI.01062-19. [PMID: 31270230 DOI: 10.1128/jvi.01062-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/01/2019] [Indexed: 01/06/2023] Open
Abstract
Cellular and viral factors participate in the replication cycle of rotavirus. We report that the guanine nucleotide exchange factor GBF1, which activates the small GTPase Arf1 to induce COPI transport processes, is required for rotavirus replication since knocking down GBF1 expression by RNA interference or inhibiting its activity by treatment with brefeldin A (BFA) or Golgicide A (GCA) significantly reduces the yield of infectious viral progeny. This reduction in virus yield was related to a block in virus assembly, since in the presence of either BFA or GCA, the assembly of infectious mature triple-layered virions was significantly prevented and only double-layered particles were detected. We report that the catalytic activity of GBF1, but not the activation of Arf1, is essential for the assembly of the outer capsid of rotavirus. We show that both BFA and GCA, as well as interfering with the synthesis of GBF1, alter the electrophoretic mobility of glycoproteins VP7 and NSP4 and block the trimerization of the virus surface protein VP7, a step required for its incorporation into virus particles. Although a posttranslational modification of VP7 (other than glycosylation) could be related to the lack of trimerization, we found that NSP4 might also be involved in this process, since knocking down its expression reduces VP7 trimerization. In support, recombinant VP7 protein overexpressed in transfected cells formed trimers only when cotransfected with NSP4.IMPORTANCE Rotavirus, a member of the family Reoviridae, is the major cause of severe diarrhea in children and young animals worldwide. Despite significant advances in the characterization of the biology of this virus, the mechanisms involved in morphogenesis of the virus particle are still poorly understood. In this work, we show that the guanine nucleotide exchange factor GBF1, relevant for COPI/Arf1-mediated cellular vesicular transport, participates in the replication cycle of the virus, influencing the correct processing of viral glycoproteins VP7 and NSP4 and the assembly of the virus surface proteins VP7 and VP4.
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6
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Garcés Suárez Y, Martínez JL, Torres Hernández D, Hernández HO, Pérez-Delgado A, Méndez M, Wood CD, Rendon-Mancha JM, Silva-Ayala D, López S, Guerrero A, Arias CF. Nanoscale organization of rotavirus replication machineries. eLife 2019; 8:e42906. [PMID: 31343403 PMCID: PMC6692110 DOI: 10.7554/elife.42906] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 07/22/2019] [Indexed: 12/18/2022] Open
Abstract
Rotavirus genome replication and assembly take place in cytoplasmic electron dense inclusions termed viroplasms (VPs). Previous conventional optical microscopy studies observing the intracellular distribution of rotavirus proteins and their organization in VPs have lacked molecular-scale spatial resolution, due to inherent spatial resolution constraints. In this work we employed super-resolution microscopy to reveal the nanometric-scale organization of VPs formed during rotavirus infection, and quantitatively describe the structural organization of seven viral proteins within and around the VPs. The observed viral components are spatially organized as five concentric layers, in which NSP5 localizes at the center of the VPs, surrounded by a layer of NSP2 and NSP4 proteins, followed by an intermediate zone comprised of the VP1, VP2, VP6. In the outermost zone, we observed a ring of VP4 and finally a layer of VP7. These findings show that rotavirus VPs are highly organized organelles.
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Affiliation(s)
- Yasel Garcés Suárez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Jose L Martínez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - David Torres Hernández
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
- Laboratorio Nacional de Microscopía Avanzada, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Haydee Olinca Hernández
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
- Laboratorio Nacional de Microscopía Avanzada, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Arianna Pérez-Delgado
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Mayra Méndez
- Centro de Investigación en Ciencias, Instituto de Investigación en Ciencias Básicas y AplicadasUniversidad Autónoma del Estado de MorelosCuernavacaMexico
| | - Christopher D Wood
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
- Laboratorio Nacional de Microscopía Avanzada, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Juan Manuel Rendon-Mancha
- Centro de Investigación en Ciencias, Instituto de Investigación en Ciencias Básicas y AplicadasUniversidad Autónoma del Estado de MorelosCuernavacaMexico
| | - Daniela Silva-Ayala
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Susana López
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Adán Guerrero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
- Laboratorio Nacional de Microscopía Avanzada, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
| | - Carlos F Arias
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de BiotecnologíaUniversidad Nacional Autónoma de MéxicoMexico CityMexico
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7
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Ren L, Ding S, Song Y, Li B, Ramanathan M, Co J, Amieva MR, Khavari PA, Greenberg HB. Profiling of rotavirus 3'UTR-binding proteins reveals the ATP synthase subunit ATP5B as a host factor that supports late-stage virus replication. J Biol Chem 2019; 294:5993-6006. [PMID: 30770472 DOI: 10.1074/jbc.ra118.006004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 02/09/2019] [Indexed: 12/22/2022] Open
Abstract
Genome replication and virion assembly of segmented RNA viruses are highly coordinated events, tightly regulated by sequence and structural elements in the UTRs of viral RNA. This process is poorly defined and likely requires the participation of host proteins in concert with viral proteins. In this study, we employed a proteomics-based approach, named RNA-protein interaction detection (RaPID), to comprehensively screen for host proteins that bind to a conserved motif within the rotavirus (RV) 3' terminus. Using this assay, we identified ATP5B, a core subunit of the mitochondrial ATP synthase, as having high affinity to the RV 3'UTR consensus sequences. During RV infection, ATP5B bound to the RV 3'UTR and co-localized with viral RNA and viroplasm. Functionally, siRNA-mediated genetic depletion of ATP5B or other ATP synthase subunits such as ATP5A1 and ATP5O reduced the production of infectious viral progeny without significant alteration of intracellular viral RNA levels or RNA translation. Chemical inhibition of ATP synthase diminished RV yield in both conventional cell culture and in human intestinal enteroids, indicating that ATP5B positively regulates late-stage RV maturation in primary intestinal epithelial cells. Collectively, our results shed light on the role of host proteins in RV genome assembly and particle formation and identify ATP5B as a novel pro-RV RNA-binding protein, contributing to our understanding of how host ATP synthases may galvanize virus growth and pathogenesis.
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Affiliation(s)
- Lili Ren
- From the Department of Medicine, Division of Gastroenterology and Hepatology, Stanford, California 94305; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305; the Palo Alto Veterans Institute of Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304; the School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing 211816, China
| | - Siyuan Ding
- From the Department of Medicine, Division of Gastroenterology and Hepatology, Stanford, California 94305; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305; the Palo Alto Veterans Institute of Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304.
| | - Yanhua Song
- From the Department of Medicine, Division of Gastroenterology and Hepatology, Stanford, California 94305; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305; the Palo Alto Veterans Institute of Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304; the Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Bin Li
- From the Department of Medicine, Division of Gastroenterology and Hepatology, Stanford, California 94305; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305; the Palo Alto Veterans Institute of Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304; the Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Muthukumar Ramanathan
- the Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Julia Co
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305
| | - Manuel R Amieva
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305
| | - Paul A Khavari
- the Palo Alto Veterans Institute of Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304; the Program in Epithelial Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Harry B Greenberg
- From the Department of Medicine, Division of Gastroenterology and Hepatology, Stanford, California 94305; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305; the Palo Alto Veterans Institute of Research, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304.
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8
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Nair N, Feng N, Blum LK, Sanyal M, Ding S, Jiang B, Sen A, Morton JM, He XS, Robinson WH, Greenberg HB. VP4- and VP7-specific antibodies mediate heterotypic immunity to rotavirus in humans. Sci Transl Med 2018. [PMID: 28637924 DOI: 10.1126/scitranslmed.aam5434] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human rotaviruses (RVs) are the leading cause of severe diarrhea in young children worldwide. The molecular mechanisms underlying the rapid induction of heterotypic protective immunity to RV, which provides the basis for the efficacy of licensed monovalent RV vaccines, have remained unknown for more than 30 years. We used RV-specific single cell-sorted intestinal B cells from human adults, barcode-based deep sequencing of antibody repertoires, monoclonal antibody expression, and serologic and functional characterization to demonstrate that infection-induced heterotypic immunoglobulins (Igs) primarily directed to VP5*, the stalk region of the RV attachment protein, VP4, are able to mediate heterotypic protective immunity. Heterotypic protective Igs against VP7, the capsid glycoprotein, and VP8*, the cell-binding region of VP4, are also generated after infection; however, our data suggest that homotypic anti-VP7 and non-neutralizing VP8* responses occur more commonly in people. These results indicate that humans can circumvent the extensive serotypic diversity of circulating RV strains by generating frequent heterotypic neutralizing antibody responses to VP7, VP8*, and most often, to VP5* after natural infection. These findings further suggest that recombinant VP5* may represent a useful target for the development of an improved, third-generation, broadly effective RV vaccine and warrants more direct examination.
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Affiliation(s)
- Nitya Nair
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ningguo Feng
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Lisa K Blum
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mrinmoy Sanyal
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Siyuan Ding
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Baoming Jiang
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
| | - Adrish Sen
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - John M Morton
- Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xiao-Song He
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - William H Robinson
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA.,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
| | - Harry B Greenberg
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. .,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.,VA Palo Alto Health Care System, Palo Alto, CA 94304, USA
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9
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Mohamed N, Nilsson E, Johansson P, Klingström J, Evander M, Ahlm C, Bucht G. Development and evaluation of a broad reacting SYBR-green based quantitative real-time PCR for the detection of different hantaviruses. J Clin Virol 2013; 56:280-5. [PMID: 23290388 DOI: 10.1016/j.jcv.2012.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 10/27/2012] [Accepted: 12/03/2012] [Indexed: 12/23/2022]
Abstract
BACKGROUND Hantaviruses are endemic in most parts of the world and cause hundreds of thousand human cases of hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS) annually throughout Eurasia and the Americas. They are zoonotic viruses, most commonly transmitted to humans by aerosolized rodent excreta. New hantaviruses are frequently discovered in previously unknown reservoir species and geographic areas. Consequently, there is a need to improve hantavirus diagnostics. OBJECTIVES This paper describes the design and evaluation of a rapid and robust quantitative real-time PCR (QRT-PCR) assay able to detect a wide range of hantaviruses. STUDY DESIGN Primers with the potential to detect different hantaviruses were designed from conserved regions of different hantavirus L segments, as identified from multiple sequence alignments. RESULTS By using SYBR-green-based QRT-PCR 100-1000 target molecules of in vitro produced RNA and less than 100 copies of hantavirus RNA from different hantavirus clades and regions of the world were detected. When using the assay on clinical samples from patients with acute HFRS, Puumala hantavirus (PUUV) RNA was confirmed in all previously positive samples. Notably, the broad reacting L-segment QRT-PCR also detected viral RNA in HFRS patient samples, previously negative by a QRT-PCR targeting the S segment of PUUV. CONCLUSIONS This novel assay provides a powerful tool for diagnosis of hantaviruses from different clades and regions and may also be useful in surveys with the purpose of finding new hantaviruses in rodent or insectivore species.
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Affiliation(s)
- Nahla Mohamed
- Department of Clinical Microbiology, Infectious Diseases, Umeå University, SE-901 85 Umeå, Sweden
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10
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Cross-linking of rotavirus outer capsid protein VP7 by antibodies or disulfides inhibits viral entry. J Virol 2011; 85:10509-17. [PMID: 21849465 DOI: 10.1128/jvi.00234-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Antibodies that neutralize rotavirus infection target outer coat proteins VP4 and VP7 and inhibit viral entry. The structure of a VP7-Fab complex (S. T. Aoki, et al., Science 324:1444-1447, 2009) led us to reclassify epitopes into two binding regions at inter- and intrasubunit boundaries of the calcium-dependent trimer. It further led us to show that antibodies binding at the intersubunit boundary inhibit uncoating of the virion outer layer. We have now tested representative antibodies for each of the defined structural epitope regions and find that antibodies recognizing epitopes in either binding region neutralize by cross-linking VP7 trimers. Antibodies that bind at the intersubunit junction neutralize as monovalent Fabs, while those that bind at the intrasubunit region require divalency. The VP7 structure has also allowed us to design a disulfide cross-linked VP7 mutant which recoats double-layered particles (DLPs) as efficiently as does wild-type VP7 but which yields particles defective in cell entry as determined both by lack of infectivity and by loss of α-sarcin toxicity in the presence of recoated particles. We conclude that dissociation of the VP7 trimer is an essential step in viral penetration into cells.
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11
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Productive dengue virus infection of human endothelial cells is directed by heparan sulfate-containing proteoglycan receptors. J Virol 2011; 85:9478-85. [PMID: 21734047 DOI: 10.1128/jvi.05008-11] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Dengue virus causes leakage of the vascular endothelium, resulting in dengue hemorrhagic fever and dengue shock syndrome. The endothelial cell lining of the vasculature regulates capillary permeability and is altered by immune and chemokine responses which affect fluid barrier functions of the endothelium. Our findings indicate that human endothelial cells are highly susceptible to infection by dengue virus (type 4). We found that dengue virus productively infects ∼80% of primary human endothelial cells, resulting in the rapid release of ∼10(5) virions 1 day postinfection. Analysis of potential inhibitors of dengue virus entry demonstrated that antibodies and ligands to integrins and cellular receptors were unable to inhibit dengue virus infection of endothelial cells. In contrast, pretreating cells with heparin or heparan sulfate resulted in a 60 to 80% reduction in dengue virus-infected cells, and pretreatment of endothelial cells with heparinase III or protease reduced dengue infectivity by >80%. Dengue virus bound specifically to resin immobilized heparin, and binding was competitively inhibited by excess heparin but not other ligands. Collectively, these findings suggest that dengue virus specifically attaches to heparan sulfate-containing proteoglycan receptors on endothelial cells. Following attachment to human endothelial cell receptors, dengue virus causes a highly productive infection that has the potential to increase viral dissemination and viremia. This provides the potential for dengue virus-infected endothelial cells to directly alter barrier functions of the endothelium, contribute to enhancement of immune cell activation, and serve as potential targets of immune responses which play a central role in dengue pathogenesis.
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Marelli B, Perez AR, Banchio C, de Mendoza D, Magni C. Oral immunization with live Lactococcus lactis expressing rotavirus VP8* subunit induces specific immune response in mice. J Virol Methods 2011; 175:28-37. [DOI: 10.1016/j.jviromet.2011.04.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 04/06/2011] [Accepted: 04/12/2011] [Indexed: 12/20/2022]
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Rhesus rotavirus entry into a polarized epithelium is endocytosis dependent and involves sequential VP4 conformational changes. J Virol 2010; 85:2492-503. [PMID: 21191022 DOI: 10.1128/jvi.02082-10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Rotavirus (RV) cell entry is an incompletely understood process, involving VP4 and VP7, the viral proteins composing the outermost layer of the nonenveloped RV triple-layered icosahedral particle (TLP), encasing VP6. VP4 can exist in three conformational states: soluble, cleaved spike, and folded back. In order to better understand the events leading to RV entry, we established a detection system to image input virus by monitoring the rhesus RV (RRV) antigens VP4, VP6, and VP7 at very early times postinfection. We provide evidence that decapsidation occurs directly after cell membrane penetration. We also demonstrate that several VP4 and VP7 conformational changes take place during entry. In particular, we detected, for the first time, the generation of folded-back VP5 in the context of the initiation of infection. Folded-back VP5 appears to be limited to the entry step. We furthermore demonstrate that RRV enters the cell cytoplasm through an endocytosis pathway. The endocytosis hypothesis is supported by the colocalization of RRV antigens with the early endosome markers Rab4 and Rab5. Finally, we provide evidence that the entry process is likely dependent on the endocytic Ca(2+) concentration, as bafilomycin A1 treatment as well as an augmentation of the extracellular calcium reservoir using CaEGTA, which both lead to an elevated intraendosomal calcium concentration, resulted in the accumulation of intact virions in the actin network. Together, these findings suggest that internalization, decapsidation, and cell membrane penetration involve endocytosis, calcium-dependent uncoating, and VP4 conformational changes, including a fold-back.
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Narváez CF, Franco MA, Angel J, Morton JM, Greenberg HB. Rotavirus differentially infects and polyclonally stimulates human B cells depending on their differentiation state and tissue of origin. J Virol 2010; 84:4543-55. [PMID: 20164228 PMCID: PMC2863723 DOI: 10.1128/jvi.02550-09] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/08/2010] [Indexed: 12/12/2022] Open
Abstract
We have shown previously that rotavirus (RV) can infect murine intestinal B220(+) cells in vivo (M. Fenaux, M. A. Cuadras, N. Feng, M. Jaimes, and H. B. Greenberg, J. Virol. 80:5219-5232, 2006) and human blood B cells in vitro (M. C. Mesa, L. S. Rodriguez, M. A. Franco, and J. Angel, Virology 366:174-184, 2007). However, the effect of RV on B cells, especially those present in the human intestine, the primary site of RV infection, is unknown. Here, we compared the effects of the in vitro RV infection of human circulating (CBC) and intestinal B cells (IBC). RV infected four times more IBC than CBC, and in both types of B cells the viral replication was highly restricted to the memory subset. RV induced cell death in 30 and 3% of infected CBC and IBC, respectively. Moreover, RV induced activation and differentiation into antibody-secreting cells (ASC) of CBC but not IBC when the B cells were present with other mononuclear cells. However, RV did not induce these effects in purified CBC or IBC, suggesting the participation of other cells in activating and differentiating CBC. RV infection was associated with enhanced interleukin-6 (IL-6) production by CBC independent of viral replication. The infection of the anti-B-cell receptor, lipopolysaccharide, or CpG-stimulated CBC reduced the secretion of IL-6 and IL-8 and decreased the number of ASC. These inhibitory effects were associated with an increase in viral replication and cell death and were observed in polyclonally stimulated CBC but not in IBC. Thus, RV differentially interacts with primary human B cells depending on their tissue of origin and differentiation stage, and it affects their capacity to modulate the local and systemic immune responses.
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Affiliation(s)
- Carlos F. Narváez
- Department of Medicine, Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, Instituto de Genética Humana, Pontificia Universidad Javeriana, Bogotá, Colombia, Department of Surgery, Stanford University School of Medicine, Stanford, California 94305
| | - Manuel A. Franco
- Department of Medicine, Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, Instituto de Genética Humana, Pontificia Universidad Javeriana, Bogotá, Colombia, Department of Surgery, Stanford University School of Medicine, Stanford, California 94305
| | - Juana Angel
- Department of Medicine, Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, Instituto de Genética Humana, Pontificia Universidad Javeriana, Bogotá, Colombia, Department of Surgery, Stanford University School of Medicine, Stanford, California 94305
| | - John M. Morton
- Department of Medicine, Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, Instituto de Genética Humana, Pontificia Universidad Javeriana, Bogotá, Colombia, Department of Surgery, Stanford University School of Medicine, Stanford, California 94305
| | - Harry B. Greenberg
- Department of Medicine, Microbiology & Immunology, Stanford University School of Medicine, Stanford, California 94305, Instituto de Genética Humana, Pontificia Universidad Javeriana, Bogotá, Colombia, Department of Surgery, Stanford University School of Medicine, Stanford, California 94305
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Rotavirus-like particles: a novel nanocarrier for the gut. J Biomed Biotechnol 2010; 2010:317545. [PMID: 20414353 PMCID: PMC2856017 DOI: 10.1155/2010/317545] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Revised: 11/23/2009] [Accepted: 02/04/2010] [Indexed: 01/26/2023] Open
Abstract
The delivery of bioactive molecules directly to damaged tissues represents a technological challenge. We propose here a new system based on virus-like particles (VLP) from rotavirus, with a marked tropism for the gut to deliver bio-active molecules to intestinal cells. For this, nonreplicative VLP nanoparticles were constructed using a baculovirus expression system and used to deliver an exogenous biomolecule, the green fluorescent protein (GFP), into either MA104 cells or intestinal cells from healthy and 2,4,6-trinitrobenzene sulfonic acid (TNBS)-treated mice. Our results show that expression of rotavirus capsid proteins in baculovirus led to the auto assembly of VLP that display similar properties to rotavirus. In vitro experiments showed that VLP were able to enter into MA104 cells and deliver the reporter protein. Intragastric administration of fluorescent VLP in healthy and TNBS-treated mice resulted in the detection of GFP and viral proteins in intestinal samples. Our results demonstrate an efficient entry of non-replicative rotavirus VLP into the epithelial cell line MA104 and provide the first in vivo evidence of the potential of these nanoparticles as a promising safe candidate for drug delivery to intestinal cells.
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16
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Abstract
During rotavirus entry, a virion penetrates a host cell membrane, sheds its outer capsid proteins, and releases a transcriptionally active subviral particle into the cytoplasm. VP5, the rotavirus protein believed to interact with the membrane bilayer, is a tryptic cleavage product of the outer capsid spike protein, VP4. When a rotavirus particle uncoats, VP5 folds back, in a rearrangement that resembles the fusogenic conformational changes in enveloped-virus fusion proteins. We present direct experimental evidence that this rearrangement leads to membrane binding. VP5 does not associate with liposomes when mounted as part of the trypsin-primed spikes on intact virions, nor does it do so after it has folded back into a stably trimeric, low-energy state. But it does bind liposomes when they are added to virions before uncoating, and VP5 rearrangement is then triggered by addition of EDTA. The presence of liposomes during the rearrangement enhances the otherwise inefficient VP5 conformational change. A VP5 fragment, VP5CT, produced from monomeric recombinant VP4 by successive treatments with chymotrypsin and trypsin, also binds liposomes only when the proteolysis proceeds in their presence. A monoclonal antibody that neutralizes infectivity by blocking a postattachment entry event also blocks VP5 liposome association. We propose that VP5 binds lipid bilayers in an intermediate conformational state, analogous to the extended intermediate conformation of enveloped-virus fusion proteins.
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17
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Abstract
Trypsin primes rotavirus for efficient infectivity by cleaving the spike protein, VP4, into VP8* and VP5*. A recombinant VP5* fragment has a trimeric, folded-back structure. Comparison of this structure with virion spikes suggests that a rearrangement, analogous to those of enveloped virus fusion proteins, may mediate membrane penetration by rotavirus during entry. To detect this inferred rearrangement of virion-associated authentic VP5*, we raised conformation-specific monoclonal antibodies against the recombinant VP5* fragment in its putative post-membrane penetration conformation. Using one of these antibodies, we demonstrate that rotavirus uncoating triggers a conformational change in the cleaved VP4 spike to yield rearranged VP5*.
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18
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Aoki ST, Settembre EC, Trask SD, Greenberg HB, Harrison SC, Dormitzer PR. Structure of rotavirus outer-layer protein VP7 bound with a neutralizing Fab. Science 2009; 324:1444-7. [PMID: 19520960 DOI: 10.1126/science.1170481] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Rotavirus outer-layer protein VP7 is a principal target of protective antibodies. Removal of free calcium ions (Ca2+) dissociates VP7 trimers into monomers, releasing VP7 from the virion, and initiates penetration-inducing conformational changes in the other outer-layer protein, VP4. We report the crystal structure at 3.4 angstrom resolution of VP7 bound with the Fab fragment of a neutralizing monoclonal antibody. The Fab binds across the outer surface of the intersubunit contact, which contains two Ca2+ sites. Mutations that escape neutralization by other antibodies suggest that the same region bears the epitopes of most neutralizing antibodies. The monovalent Fab is sufficient to neutralize infectivity. We propose that neutralizing antibodies against VP7 act by stabilizing the trimer, thereby inhibiting the uncoating trigger for VP4 rearrangement. A disulfide-linked trimer is a potential subunit immunogen.
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Affiliation(s)
- Scott T Aoki
- Laboratory of Molecular Medicine, Children's Hospital, Boston, MA 02115, USA
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19
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Bellido D, Craig PO, Mozgovoj MV, Gonzalez DD, Wigdorovitz A, Goldbaum FA, Dus Santos MJ. Brucella spp. lumazine synthase as a bovine rotavirus antigen delivery system. Vaccine 2009; 27:136-45. [DOI: 10.1016/j.vaccine.2008.10.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 09/30/2008] [Accepted: 10/02/2008] [Indexed: 11/29/2022]
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20
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Gualtero DF, Guzmán F, Acosta O, Guerrero CA. Amino acid domains 280–297 of VP6 and 531–554 of VP4 are implicated in heat shock cognate protein hsc70-mediated rotavirus infection. Arch Virol 2007; 152:2183-96. [PMID: 17876681 DOI: 10.1007/s00705-007-1055-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 08/08/2007] [Indexed: 12/17/2022]
Abstract
The rotavirus infection mechanism seems to be a multi-step process which is still not fully understood. The heat shock cognate protein hsc70 has been proposed as being a co-receptor molecule for rotavirus entry into susceptible cells. In this work, an attempt was made to determine the existence of possible domains for VP4 and VP6 binding to hsc70. We selected amino acid sequences 531-554 from VP4 and 280-297 from VP6 on the basis of already recognized sequences for binding to hsc70. This study determined that DLPs and synthetic peptides from VP6 (aa 280-297) and VP4 (aa 531-554), individually or in combination, inhibited rotavirus RRV, YM and WA entry into MA104 and Caco-2 cells in an additive and dose-dependent manner. Hyperimmune sera against these synthetic peptides blocked infection by infectious TLPs. Capture ELISA results showed that DLPs interact with hsc70, probably through VP6 as the specific interaction between hcs70 and DLPs was disrupted by a VP6 peptide. These results suggest that VP6 takes part during rotavirus cell entry by binding to hsc70. This, as well as previous work, provides insight concerning the function of hsc70 within a multi-step model of rotavirus entry.
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Affiliation(s)
- D F Gualtero
- Departamento de Ciencias Fisiológicas, Facultad de Medicina-Instituto de Biotecnología, Universidad Nacional de Colombia, Bogotá, Colombia
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21
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Fleming FE, Graham KL, Taniguchi K, Takada Y, Coulson BS. Rotavirus-neutralizing antibodies inhibit virus binding to integrins alpha 2 beta 1 and alpha 4 beta 1. Arch Virol 2007; 152:1087-101. [PMID: 17318737 DOI: 10.1007/s00705-007-0937-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Accepted: 01/08/2007] [Indexed: 11/25/2022]
Abstract
Rotavirus outer capsid proteins VP5(*), VP8(*) and VP7 elicit neutralizing, protective antibodies. The alpha 2 beta 1 integrin is a cellular receptor for rotavirus that is bound by VP5(*). Some rotaviruses also recognize the alpha 4 beta 1 integrin. In this study, the effects of antibodies to rotavirus on virus binding to recombinant alpha 2 beta 1 and alpha 4 beta 1 expressed on K562 cells were determined. All neutralizing monoclonal antibodies to VP5(*) tested (YO-2C2, 2G4, 1A10) and two to VP7 (RV-3:2, RV-4:2) inhibited rotavirus binding to alpha 2 beta 1. Rotavirus binding to alpha 4 beta 1 was reduced by 2G4 and neutralizing antibody F45:2, directed to VP7. However, a neutralizing antibody to VP8(*) (RV-5:2) and one to VP7 (RV-3:1) did not affect rotavirus binding to these integrins. Virus-cell binding was unaffected by non-neutralizing antibody RVA to the rotavirus inner capsid protein VP6. The attachment of human rotavirus strain Wa to these integrins was inhibited by infection sera with neutralizing activity collected from two children hospitalised with severe rotavirus gastroenteritis. A negative reference serum did not affect rotavirus-cell attachment. As the binding of rotaviruses to alpha 2 beta 1 and alpha 4 beta 1 is inhibited by neutralizing antibodies to VP5(*) and VP7, and serum from children with rotavirus disease, rotavirus recognition of these integrins may be important for host infection.
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Affiliation(s)
- F E Fleming
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Australia
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22
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Trask SD, Dormitzer PR. Assembly of highly infectious rotavirus particles recoated with recombinant outer capsid proteins. J Virol 2006; 80:11293-304. [PMID: 16971442 PMCID: PMC1642144 DOI: 10.1128/jvi.01346-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Assembly of the rotavirus outer capsid is the final step of a complex pathway. In vivo, the later steps include a maturational membrane penetration that is dependent on the scaffolding activity of a viral nonstructural protein. In vitro, simply adding the recombinant outer capsid proteins VP4 and VP7 to authentic double-layered rotavirus subviral particles (DLPs) in the presence of calcium and acidic pH increases infectivity by a factor of up to 10(7), yielding particles as infectious as authentic purified virions. VP4 must be added before VP7 for high-level infectivity. Steep dependence of infectious recoating on VP4 concentration suggests that VP4-VP4 interactions, probably oligomerization, precede VP4 binding to particles. Trypsin sensitivity analysis identifies two populations of VP4 associated with recoated particles: properly mounted VP4 that can be specifically primed by trypsin, and nonspecifically associated VP4 that is degraded by trypsin. A full complement of properly assembled VP4 is not required for efficient infectivity. Minimal dependence of recoating on VP7 concentration suggests that VP7 binds DLPs with high affinity. The parameters for efficient recoating and the characterization of recoated particles suggest a model in which, after a relatively weak interaction between oligomeric VP4 and DLPs, VP7 binds the particles and locks VP4 in place. Recoating will allow the use of infectious modified rotavirus particles to explore rotavirus assembly and cell entry and could lead to practical applications in novel immunization strategies.
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Affiliation(s)
- Shane D Trask
- Children's Hospital, Enders 673, 320 Longwood Ave., Boston, MA 02115, USA
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Silvestri LS, Tortorici MA, Vasquez-Del Carpio R, Patton JT. Rotavirus glycoprotein NSP4 is a modulator of viral transcription in the infected cell. J Virol 2006; 79:15165-74. [PMID: 16306588 PMCID: PMC1316041 DOI: 10.1128/jvi.79.24.15165-15174.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The outer shell of the rotavirus triple-layered virion is lost during cell entry, yielding a double-layered particle (DLP) that directs synthesis of viral plus-strand RNAs. The plus-strand RNAs act as templates for synthesis of the segmented double-stranded RNA (dsRNA) genome in viral inclusion bodies (viroplasms). The viral endoplasmic reticulum (ER)-resident glycoprotein NSP4 recruits progeny DLPs formed in viroplasms to the ER, where the particles are converted to triple-layered particles (TLPs) via budding. In this study, we have used short interfering RNAs to probe the role of NSP4 in the viral life cycle. Our analysis showed that knockdown of NSP4 expression had no marked effect on the expression of other viral proteins or on the replication of the dsRNA genome segments. However, NSP4 loss of function suppressed viroplasm maturation and caused a maldistribution of nonstructural and structural proteins that normally accumulate in viroplasms. NSP4 loss of function also inhibited formation of packaged virus particles, instead inducing the accumulation of empty particles. Most significant was the observation that NSP4 knockdown led to dramatically increased levels of viral transcription late in the infection cycle. These findings point to a multifaceted role for NSP4 in virus replication, including influencing the development of viroplasms, linking genome packaging with particle assembly, and acting as a modulator of viral transcription. By recruiting transcriptionally active or potentially active DLPs to the ER for conversion to quiescent TLPs, NSP4 acts as a feedback inhibitor down-regulating viral transcription when adequate levels of plus-strand RNAs are available to allow for productive infection.
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Affiliation(s)
- Lynn S Silvestri
- Laboratory of Infectious Diseases, NIAID, National Institutes of Health, 50 South Dr., MSC 8026, Room 6314, Bethesda, MD 20892-8026, USA
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Rollo EE, Hempson SJ, Bansal A, Tsao E, Habib I, Rittling SR, Denhardt DT, Mackow ER, Shaw RD. The cytokine osteopontin modulates the severity of rotavirus diarrhea. J Virol 2005; 79:3509-16. [PMID: 15731245 PMCID: PMC1075680 DOI: 10.1128/jvi.79.6.3509-3516.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Osteopontin (OPN) is a sialated phosphoprotein found in tissues and secreted into body fluids. It is an integrin ligand with pleiotropic functions as an extracellular matrix protein in mineralized tissues and a cytokine that is active in cell signaling (A. B. Tuck, C. Hota, S. M. Wilson, and A. F. Chambers, Oncogene 22:1198-1205, 2003). To determine whether OPN may be important in mucosal defense against viral pathogens, we evaluated the OPN response to rotavirus infection and the extent of diarrhea manifested by infected opn null mutant (opn-/-) mice. Reverse transcription-PCR, Northern and Western blots, and immunohistochemical studies of the HT-29 intestinal epithelial cell line and murine intestine were used to evaluate OPN mRNA and product. Intestinal closed loops and diarrheal observations determined disease severity and duration. OPN mRNA levels increased after infection of HT-29 cells, peaking in 4 to 6 h. Infected cultures contained 925 microg of OPN/ml, while for controls the levels were below detection (50 microg/ml). Infection increased OPN mRNA levels in intestinal tissue between 2 and 24 h postinoculation and increased OPN protein in intestinal fluid. The cellular localization of OPN was supranuclear and apical, and responding cells were diffusely distributed on the villus surface. Three days after infection, closed intestinal loops from opn-/- mice contained more fluid than loops from controls, although secretion levels at the onset of illness were similar. Null mutant mice experienced more intense and prolonged diarrhea than controls. Rotavirus infection of intestinal epithelial cells and murine intestine caused marked increases in OPN mRNA levels and secreted OPN protein. OPN-deficient mice suffered prolonged disease.
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Affiliation(s)
- Ellen E Rollo
- Research Service (151), Northport V.A. Medical Center, Northport, NY 11768, USA
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Fontes LVQ, Campos GS, Beck PA, Brandão CFL, Sardi SI. Precipitation of bovine rotavirus by polyethylene [corrected] glycol (PEG) and its application to produce polyclonal and monoclonal antibodies. J Virol Methods 2005; 123:147-53. [PMID: 15620396 DOI: 10.1016/j.jviromet.2004.09.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Revised: 09/04/2004] [Accepted: 09/24/2004] [Indexed: 11/17/2022]
Abstract
Many protocols are available to produce monoclonal antibodies (MAbs) against bovine rotavirus (BRV) using purified virus particles but those methods are time-consuming and produce substantial loss of virus structure or infectivity. Polyethylene gycol (PEG) viral precipitation was investigated as a possible alternative method to obtain purified virus and viral antigen for monoclonal and polyclonal antibodies production. The antigenic mass inoculated into rabbits was sufficient to obtain a polyclonal hyperimmune serum with neutralizing activity and a wide range of humoral responses to different viral proteins with minimum cellular contamination. This antigenic mass inoculated into mice was capable of producing seven MAbs with different biochemical characteristics (Western-blot; indirect immunofluorescence and serum neutralization assays). When evaluated as diagnostic tools to detect BRV antigen in feces the MAbs were effective for detecting rotavirus in naturally infected calves. This work demonstrate that PEG precipitation could be an useful procedure for obtaining viral antigen to produce polyclonal and MAbs against BRV. The antigenic mass obtained, the viral infectivity, and the conserved protein pattern suggest that this methodology could be applied to this and to other viruses, reducing time or possible loss of antigens involved in viral purification.
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Affiliation(s)
- Lia Vale Queiroz Fontes
- Laboratório de virologia, Instituto de Ciências da Saúde, Universidade Federal da Bahia, Salvador, 40110-100 Bahia, Brazil
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Bányai K, Gentsch JR, Schipp R, Jakab F, Meleg E, Mihály I, Szücs G. Dominating prevalence of P[8],G1 and P[8],G9 rotavirus strains among children admitted to hospital between 2000 and 2003 in Budapest, Hungary. J Med Virol 2005; 76:414-23. [PMID: 15902709 DOI: 10.1002/jmv.20372] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Group A rotaviruses are the main cause of acute dehydrating diarrhea in children, responsible for high mortality in developing countries and a significant socio-economic burden associated with treating the disease in developed countries. Two rotavirus vaccine candidates predicated on either homotypic or heterotypic protection have undergone clinical trials recently and await licensure for routine use. In anticipation of a future vaccination campaign in Hungary, the diversity of rotaviruses collected from Budapest between 2000 and 2003 were analyzed by polyacrylamide gel electrophoresis (PAGE) of the viral genome and by serotyping and genotyping of the outer capsid genes, VP7 and VP4. Among 2,763 rotavirus positive specimens available for analysis, we were able to determine the electropherotype of 2,227, and, of these, 1,517 (68.1%) were subjected to G typing and 1,173 (52.7%) were subjected to P typing. We successfully G typed 1,481 (97.6%) and P typed 1,130 (96.3%) strains, respectively. A total of six G types (G1, 50.2%; G2, 2.2%; G3, 1.7%; G4, 5.8%; G6, 0.6%; and G9, 34.4%) and four P types (P[4], 3.0%; P[6], 0.7%; P[8], 89.9%; and P[9], 1.7%) were identified in nine individual combinations (P[8],G1; P[4],G2; P[8],G3; P[8],G4; P[8],G9; P[6],G4; P[4],G1; P[9],G3; and P[9],G6). The prevalence of VP7 and VP4 specificities varied from year to year. In this regard, a shift in serotype predominance from G1 in 2000-2001 (61.8%) and 2001-2002 (69.7%) to G9 in 2002-2003 (51.3%) was an intriguing observation that has been reported recently in some other countries, as well. The emergence of serotype G9 rotaviruses in Hungary and other parts of the world may have implications for future vaccine development and use, particularly, if current vaccine candidates cannot confer adequate homotypic or heterotypic protection against these strains.
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Affiliation(s)
- Krisztián Bányai
- Regional Laboratory of Virology, Baranya County Institute of State Public Health Service, Pécs, Hungary.
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Golantsova NE, Gorbunova EE, Mackow ER. Discrete domains within the rotavirus VP5* direct peripheral membrane association and membrane permeability. J Virol 2004; 78:2037-44. [PMID: 14747568 PMCID: PMC369428 DOI: 10.1128/jvi.78.4.2037-2044.2004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cleavage of the rotavirus spike protein, VP4, is required for rotavirus-induced membrane permeability and viral entry into cells. The VP5* cleavage product selectively permeabilizes membranes and liposomes and contains an internal hydrophobic domain that is required for membrane permeability. Here we investigate VP5* domains (residues 248 to 474) that direct membrane binding. We determined that expressed VP5 fragments containing residues 248 to 474 or 265 to 474, including the internal hydrophobic domain, bind to cellular membranes but are not present in Triton X-100-resistant membrane rafts. Expressed VP5 partitions into aqueous but not detergent phases of Triton X-114, suggesting that VP5 is not integrally inserted into membranes. Since high-salt or alkaline conditions eluted VP5 from membranes, our findings demonstrate that VP5 is peripherally associated with membranes. Interestingly, mutagenesis of residue 394 (W-->R) within the VP5 hydrophobic domain, which abolishes VP5-directed permeability, had no effect on VP5's peripheral membrane association. In contrast, deletion of N-terminal VP5 residues (residues 265 to 279) abolished VP5 binding to membranes. Alanine mutagenesis of two positively charged residues within this domain (residues 274R and 276K) dramatically reduced (>95%) binding of VP5 to membranes and suggested their potential interaction with polar head groups of the lipid bilayer. Mutations in either the VP5 hydrophobic or basic domain blocked VP5-directed permeability of cells. These findings indicate that there are at least two discrete domains within VP5* required for pore formation: an N-terminal basic domain that permits VP5* to peripherally associate with membranes and an internal hydrophobic domain that is essential for altering membrane permeability. These results provide a fundamental understanding of interactions between VP5* and the membrane, which are required for rotavirus entry.
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Affiliation(s)
- Nina E Golantsova
- Department of Medicine, Stony Brook University, Stony Brook, New York 11794, USA
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Kovacs-Nolan J, Yoo D, Mine Y. Fine mapping of sequential neutralization epitopes on the subunit protein VP8 of human rotavirus. Biochem J 2003; 376:269-75. [PMID: 12901721 PMCID: PMC1223744 DOI: 10.1042/bj20021969] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2002] [Revised: 08/05/2003] [Accepted: 08/05/2003] [Indexed: 11/17/2022]
Abstract
The epitopes of the HRV (human rotavirus), especially those involved in virus neutralization, have not been determined in their entirety, and would have significant implications for HRV vaccine development. In the present study, we report on the epitope mapping and identification of sequential neutralization epitopes, on the Wa strain HRV subunit protein VP8, using synthetic overlapping peptides. Polyclonal antibodies against recombinant Wa VP8 were produced previously in chicken, and purified from egg yolk, which showed neutralizing activity against HRV in vitro. Overlapping VP8 peptide fragments were synthesized and probed with the anti-VP8 antibodies, revealing five sequential epitopes on VP8. Further analysis suggested that three of the five epitopes detected, M1-L10, I55-D66 and L223-P234, were involved in virus neutralization, indicating that sequential epitopes may also be important for the HRV neutralization. The interactions of the antibodies with the five epitopes were characterized by an examination of the critical amino acids involved in antibody binding. Epitopes comprised primarily of hydrophobic amino acid residues, followed by polar and charged residues. The more critical amino acids appeared to be located near the centre of the epitopes, with proline, isoleucine, serine, glutamine and arginine playing an important role in the binding of antibody to the VP8 epitopes.
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29
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Londrigan SL, Graham KL, Takada Y, Halasz P, Coulson BS. Monkey rotavirus binding to alpha2beta1 integrin requires the alpha2 I domain and is facilitated by the homologous beta1 subunit. J Virol 2003; 77:9486-501. [PMID: 12915563 PMCID: PMC187378 DOI: 10.1128/jvi.77.17.9486-9501.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rotaviruses utilize integrins during virus-cell interactions that lead to infection. Cell binding and infection by simian rotavirus SA11 were inhibited by antibodies (Abs) to the inserted (I) domain of the alpha2 integrin subunit. To determine directly which integrins or other proteins bind rotaviruses, cell surface proteins precipitated by rotaviruses were compared with those precipitated by anti-alpha2beta1 Abs. Two proteins precipitated by SA11 and rhesus rotavirus RRV from MA104 and Caco-2 cells migrated indistinguishably from alpha2beta1 integrin, and SA11 precipitated beta1 from alpha2beta1-transfected CHO cells. These viruses specifically precipitated two MA104 cell proteins only, but an additional 160- to 165-kDa protein was precipitated by SA11 from Caco-2 cells. The role of the alpha2 I domain in rotavirus binding, infection, and growth was examined using CHO cell lines expressing wild-type or mutated human alpha2 or alpha2beta1. Infectious SA11 and RRV, but not human rotavirus Wa, specifically bound CHO cell-expressed human alpha2beta1 and, to a lesser extent, human alpha2 combined with hamster beta1. Binding was inhibited by anti-alpha2 I domain monoclonal Abs (MAbs), but not by non-I domain MAbs to alpha2, and required the presence of the alpha2 I domain. Amino acid residues 151, 221, and 254 in the metal ion-dependent adhesion site of the alpha2 I domain that are necessary for type I collagen binding to alpha2beta1 were not essential for rotavirus binding. Rotavirus-alpha2beta1 binding led to increased virus infection and RRV growth. SA11 and RRV require the alpha2 I domain for binding to alpha2beta1, and their binding to this integrin is distinguishable from that of collagen.
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Affiliation(s)
- Sarah L Londrigan
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Graham KL, Halasz P, Tan Y, Hewish MJ, Takada Y, Mackow ER, Robinson MK, Coulson BS. Integrin-using rotaviruses bind alpha2beta1 integrin alpha2 I domain via VP4 DGE sequence and recognize alphaXbeta2 and alphaVbeta3 by using VP7 during cell entry. J Virol 2003; 77:9969-78. [PMID: 12941907 PMCID: PMC224597 DOI: 10.1128/jvi.77.18.9969-9978.2003] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Integrins alpha2beta1, alphaXbeta2, and alphaVbeta3 have been implicated in rotavirus cell attachment and entry. The virus spike protein VP4 contains the alpha2beta1 ligand sequence DGE at amino acid positions 308 to 310, and the outer capsid protein VP7 contains the alphaXbeta2 ligand sequence GPR. To determine the viral proteins and sequences involved and to define the roles of alpha2beta1, alphaXbeta2, and alphaVbeta3, we analyzed the ability of rotaviruses and their reassortants to use these integrins for cell binding and infection and the effect of peptides DGEA and GPRP on these events. Many laboratory-adapted human, monkey, and bovine viruses used integrins, whereas all porcine viruses were integrin independent. The integrin-using rotavirus strains each interacted with all three integrins. Integrin usage related to VP4 serotype independently of sialic acid usage. Analysis of rotavirus reassortants and assays of virus binding and infectivity in integrin-transfected cells showed that VP4 bound alpha2beta1, and VP7 interacted with alphaXbeta2 and alphaVbeta3 at a postbinding stage. DGEA inhibited rotavirus binding to alpha2beta1 and infectivity, whereas GPRP binding to alphaXbeta2 inhibited infectivity but not binding. The truncated VP5* subunit of VP4, expressed as a glutathione S-transferase fusion protein, bound the expressed alpha2 I domain. Alanine mutagenesis of D308 and G309 in VP5* eliminated VP5* binding to the alpha2 I domain. In a novel process, integrin-using viruses bind the alpha2 I domain of alpha2beta1 via DGE in VP4 and interact with alphaXbeta2 (via GPR) and alphaVbeta3 by using VP7 to facilitate cell entry and infection.
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Affiliation(s)
- Kate L Graham
- Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Ludert JE, Ruiz MC, Hidalgo C, Liprandi F. Antibodies to rotavirus outer capsid glycoprotein VP7 neutralize infectivity by inhibiting virion decapsidation. J Virol 2002; 76:6643-51. [PMID: 12050377 PMCID: PMC136269 DOI: 10.1128/jvi.76.13.6643-6651.2002] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The rotavirus capsid is composed of three concentric protein layers. Proteins VP4 and VP7 comprise the outer layer. VP4 forms spikes, is the viral attachment protein, and is cleaved by trypsin into VP8* and VP5*. VP7 is a glycoprotein and the major constituent of the outer protein layer. Both VP4 and VP7 induce neutralizing and protective antibodies. To gain insight into the virus neutralization mechanisms, the effects of neutralizing monoclonal antibodies (MAbs) directed against VP8*, VP5*, and VP7 on the decapsidation process of purified OSU and RRV virions were studied. Changes in virion size were followed in real time by 90 degrees light scattering. The transition from triple-layered particles to double-layered particles induced by controlled low calcium concentrations was completely inhibited by anti-VP7 MAbs but not by anti-VP8* or anti-VP5* MAbs. The inhibitory effect of the MAb directed against VP7 was concentration dependent and was abolished by papain digestion of virus-bound antibody under conditions that generated Fab fragments but not under conditions that generated F(ab')(2) fragments. Electron microscopy showed that RRV virions reacted with an anti-VP7 MAb stayed as triple-layered particles in the presence of excess EDTA. Furthermore, the infectivity of rotavirus neutralized via VP8*, but not that of rotavirus neutralized via VP7, could be recovered by lipofection of neutralized particles into MA-104 cells. These data are consistent with the notion that antibodies directed at VP8* neutralize by inhibiting binding of virus to the cell. They also indicate that antibodies directed at VP7 neutralize by inhibiting virus decapsidation, in a manner that is dependent on the bivalent binding of the antibody.
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Affiliation(s)
- Juan Ernesto Ludert
- Centro de Microbiologia. Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas 1020-A, Venezuela.
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32
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Feng N, Lawton JA, Gilbert J, Kuklin N, Vo P, Prasad BVV, Greenberg HB. Inhibition of rotavirus replication by a non-neutralizing, rotavirus VP6-specific IgA mAb. J Clin Invest 2002; 109:1203-13. [PMID: 11994409 PMCID: PMC150959 DOI: 10.1172/jci14397] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Rotaviruses are the leading cause of severe diarrheal disease in young children. Intestinal mucosal IgA responses play a critical role in protective immunity against rotavirus reinfection. Rotaviruses consist of three concentric capsid layers surrounding a genome of 11 segments of double-stranded RNA. The outer layer proteins, VP4 and VP7, which are responsible for viral attachment and entry, are targets for protective neutralizing antibodies. However, IgA mAb's directed against the intermediate capsid protein VP6, which do not neutralize the virus, have also been shown to protect mice from rotavirus infection and clear chronic infection in SCID mice. We investigated whether the anti-VP6 IgA (7D9) mAb could inhibit rotavirus replication inside epithelial cells and found that 7D9 acted at an early stage of infection to neutralize rotavirus following antibody lipofection. Using electron cryomicroscopy, we determined the three-dimensional structure of the virus-antibody complex. The attachment of 7D9 IgA to VP6 introduces a conformational change in the VP6 trimer, rendering the particle transcriptionally incompetent and preventing the elongation of initiated transcripts. Based on these observations, we suggest that anti-VP6 IgA antibodies confers protection in vivo by inhibiting viral transcription at the start of the intracellular phase of the viral replication cycle.
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Affiliation(s)
- Ningguo Feng
- Department of Gastroenterology, Stanford University School of Medicine, Stanford, California 94304, USA
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Dormitzer PR, Sun ZYJ, Wagner G, Harrison SC. The rhesus rotavirus VP4 sialic acid binding domain has a galectin fold with a novel carbohydrate binding site. EMBO J 2002; 21:885-97. [PMID: 11867517 PMCID: PMC125907 DOI: 10.1093/emboj/21.5.885] [Citation(s) in RCA: 271] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cell attachment and membrane penetration are functions of the rotavirus outer capsid spike protein, VP4. An activating tryptic cleavage of VP4 produces the N-terminal fragment, VP8*, which is the viral hemagglutinin and an important target of neutralizing antibodies. We have determined, by X-ray crystallography, the atomic structure of the VP8* core bound to sialic acid and, by NMR spectroscopy, the structure of the unliganded VP8* core. The domain has the beta-sandwich fold of the galectins, a family of sugar binding proteins. The surface corresponding to the galectin carbohydrate binding site is blocked, and rotavirus VP8* instead binds sialic acid in a shallow groove between its two beta-sheets. There appears to be a small induced fit on binding. The residues that contact sialic acid are conserved in sialic acid-dependent rotavirus strains. Neutralization escape mutations are widely distributed over the VP8* surface and cluster in four epitopes. From the fit of the VP8* core into the virion spikes, we propose that VP4 arose from the insertion of a host carbohydrate binding domain into a viral membrane interaction protein.
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Affiliation(s)
- Philip R. Dormitzer
- Laboratory of Molecular Medicine, Enders 673, Children’s Hospital, 320 Longwood Avenue, Boston, MA 02115, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 and Howard Hughes Medical Institute and the Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA Corresponding author e-mail:
| | - Zhen-Yu J. Sun
- Laboratory of Molecular Medicine, Enders 673, Children’s Hospital, 320 Longwood Avenue, Boston, MA 02115, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 and Howard Hughes Medical Institute and the Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA Corresponding author e-mail:
| | - Gerhard Wagner
- Laboratory of Molecular Medicine, Enders 673, Children’s Hospital, 320 Longwood Avenue, Boston, MA 02115, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 and Howard Hughes Medical Institute and the Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA Corresponding author e-mail:
| | - Stephen C. Harrison
- Laboratory of Molecular Medicine, Enders 673, Children’s Hospital, 320 Longwood Avenue, Boston, MA 02115, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 and Howard Hughes Medical Institute and the Department of Molecular and Cellular Biology, Harvard University, 7 Divinity Avenue, Cambridge, MA 02138, USA Corresponding author e-mail:
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Kim Y, Nielsen PR, Hodgins D, Chang KO, Saif LJ. Lactogenic antibody responses in cows vaccinated with recombinant bovine rotavirus-like particles (VLPs) of two serotypes or inactivated bovine rotavirus vaccines. Vaccine 2002; 20:1248-58. [PMID: 11803088 DOI: 10.1016/s0264-410x(01)00404-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Triple-layered virus-like particles (VLPs) were produced in a baculovirus expression system from the two prevalent bovine rotavirus (BRV) serotypes, IND (P[5]G6) and 2292B (P[11]G10). Five groups of pregnant cows were inoculated intramuscularly and intramammarily with IND VLPs [BRV RF VP2, and IND VP4, 6, and 7, 250 microg per dose], 2292B VLPs [RF VP2, Cr VP4 (P[11]), and 2292B VP6 and 7, 250 microg per dose], combined IND/2292B VLPs (125 microg each VLP per dose), inactivated IND BRV (5x10(7)PFU per dose, pre-inactivation), or cell supernatant (mock-controls) in incomplete Freund's adjuvant. Serum, colostrum and milk were collected and tested for isotype-specific antibodies, and homologous and heterologous neutralizing antibodies (VN) to BRV by ELISA and VN tests, respectively. After vaccination, the IgG1 and homologous VN geometric mean antibody titers (GMTs) to BRV in serum of vaccinated groups were significantly (P<0.05) higher than in the mock-controls through postpartum day (PPD) 30. In colostrum, the IgG1 and IgA, and the homologous and heterologous VN GMTs of the IND VLP, 2292B VLP, combined IND/2292B VLP and the inactivated IND groups were significantly enhanced compared to the mock-controls, except for the heterologous VN GMTs in the inactivated IND group. However, the VLP vaccine groups had significantly higher homologous and heterologous VN GMTs than the inactivated IND group. The VN GMTs of the IND/2292B VLP group were statistically similar to the homologous VN GMTs of the IND or 2292B VLP groups, although the IgG1 GMT was lower. In milk, the IgG1 and homologous VN GMTs of the VLP groups were significantly higher than the inactivated IND or the mock-control groups through PPD30. However, the heterologous and homologous VN GMTs of inactivated IND group were statistically similar to the mock-control group at PPD0 and 30, respectively. These results demonstrate that the BRV antibody titers in serum, colostrum and milk are significantly enhanced by the use of triple-layered VLPs and inactivated IND vaccines, but significantly higher antibody responses were observed in the VLP vaccinated cows. The combined IND/2292B VLP vaccine induced comparable VN responses to BRV in serum, colostrum and milk compared to those induced by the individual IND or 2292B VLP vaccines, suggesting that at least two different serotypes can be mixed to confer maximum antibody responses to the incorporated serotypes.
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Affiliation(s)
- Y Kim
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
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35
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Tihova M, Dryden KA, Bellamy AR, Greenberg HB, Yeager M. Localization of membrane permeabilization and receptor binding sites on the VP4 hemagglutinin of rotavirus: implications for cell entry. J Mol Biol 2001; 314:985-92. [PMID: 11743716 DOI: 10.1006/jmbi.2000.5238] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The surface of rotavirus is decorated with 60 spike-like projections, each composed of a dimer of VP4, the viral hemagglutinin. Trypsin cleavage of VP4 generates two fragments, VP8*, which binds sialic acid (SA), and VP5*, containing an integrin binding motif and a hydrophobic region that permeabilizes membranes and is homologous to fusion domains. Although the mechanism for cell entry by this non-enveloped virus is unclear, it is known that trypsin cleavage enhances viral infectivity and facilitates viral entry. We used electron cryo-microscopy and difference map analysis to localize the binding sites for two neutralizing monoclonal antibodies, 7A12 and 2G4, which are directed against the SA-binding site within VP8* and the membrane permeabilization domain within VP5*, respectively. Fab 7A12 binds at the tips of the dimeric heads of VP4, and 2G4 binds in the cleft between the two heads of the spike. When these binding results are combined with secondary structure analysis, we predict that the VP4 heads are composed primarily of beta-sheets in VP8* and that VP5* forms the body and base primarily in beta-structure and alpha-helical conformations, respectively. Based on these results and those of others, a model is proposed for cell entry in which VP8* and VP5* mediate receptor binding and membrane permeabilization, and uncoating occurs during transfer across the lipid bilayer, thereby generating the transcriptionally active particle.
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Affiliation(s)
- M Tihova
- Departments of Cell and Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA
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36
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Chang KO, Vandal OH, Yuan L, Hodgins DC, Saif LJ. Antibody-secreting cell responses to rotavirus proteins in gnotobiotic pigs inoculated with attenuated or virulent human rotavirus. J Clin Microbiol 2001; 39:2807-13. [PMID: 11473996 PMCID: PMC88243 DOI: 10.1128/jcm.39.8.2807-2813.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2001] [Accepted: 05/13/2001] [Indexed: 01/01/2023] Open
Abstract
Because of their similarities to infants in mucosal immune responses and their susceptibility to human rotavirus (HRV) diarrhea, gnotobiotic pigs provide a useful model for rotaviral disease. In this study, we performed quantitative enzyme-linked immunospot (ELISPOT) assays to measure local and systemic isotype-specific antibody-secreting cell (ASC) responses to individual structural (VP4, VP6, and VP7) and nonstructural (NSP3 and NSP4) proteins of Wa HRV. The Spodoptera frugiperda cells expressing each recombinant baculovirus HRV protein were formalin fixed and used as antigen for ELISPOT assays. Neonatal gnotobiotic pigs were orally inoculated once with virulent Wa (WaV) or three times with attenuated Wa (WaA) HRV or mock inoculated (Mock) and then were challenged with virulent Wa (WaV/PC) 28 days after the first inoculation. The ASCs from intestinal and systemic lymphoid tissues of pigs from each group were quantitated by ELISPOT assay at the day of challenge, at postinoculation day 28 (WaV, WaA, and Mock) or at postchallenge day (PCD) 7 (WaV+WaV/PC, WaA+WaV/PC, and Mock+WaV/PC). In all virus-inoculated pigs, regardless of the inoculum, lymphoid tissue, or isotype, VP6 induced the highest numbers of ASCs, followed by VP4; ASCs specific for VP7, NSP3, and NSP4 were less numerous. At challenge, total HRV- and HRV protein-specific immunoglobulin A (IgA) and IgG ASCs in intestinal lymphoid tissues were significantly greater in WaV- than in WaA-inoculated pigs, and WaV pigs were fully protected against diarrhea postchallenge, whereas the WaA pigs were partially protected. At PCD 7, there were no significant differences in ASC numbers for any HRV proteins between the WaV+WaV/PC and WaA+WaV/PC groups.
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Affiliation(s)
- K O Chang
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center/The Ohio State University, Wooster, Ohio 44691, USA
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37
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LaMonica R, Kocer SS, Nazarova J, Dowling W, Geimonen E, Shaw RD, Mackow ER. VP4 differentially regulates TRAF2 signaling, disengaging JNK activation while directing NF-kappa B to effect rotavirus-specific cellular responses. J Biol Chem 2001; 276:19889-96. [PMID: 11262403 DOI: 10.1074/jbc.m100499200] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Rotaviruses rapidly activate NF-kappaB and induce the secretion of selected chemokines after infection. The ability of rotavirus particles lacking genomic RNA to activate NF-kappaB suggested that rotavirus proteins direct cell signaling responses. We identified conserved TNFR-associated factor (TRAF) binding motifs within the rotavirus capsid protein VP4 and its N-terminal VP8* cleavage product. TRAFs (-1, -2, and -3) are bound by the rhesus rotavirus VP8* protein through three discrete TRAF binding domains. Expression of VP4 or VP8* from rhesus or human rotaviruses induced a 5-7-fold increase in NF-kappaB activity and synergistically enhanced TRAF2-mediated NF-kappaB activation. Mutagenesis of VP8* TRAF binding motifs abolished VP8* binding to TRAFs and the ability of the protein to activate NF-kappaB. Expression of pathway-specific dominant negative (DN) inhibitors DN-TRAF2 or DN-NF-kappaB-inducing kinase also abolished VP8*-, VP4-, or rotavirus-mediated NF-kappaB activation. These findings demonstrate that rotavirus primarily activates NF-kappaB through a TRAF2-NF-kappaB-inducing kinase signaling pathway and that VP4 and VP8* proteins direct pathway activation through interactions with cellular TRAFs. In contrast, transcriptional responses from AP-1 reporters were inhibited 5-fold by VP8* and were not activated by rotavirus infection, suggesting the differential regulation of TRAF2 signaling responses by VP8*. VP8* blocked JNK activation directed by TRAF2 or TRAF5 but had no effect on JNK activation directed by TRAF6 or MEKK1. This establishes that fully cytoplasmic rotaviruses selectively engage signaling pathways, which regulate cellular transcriptional responses. These findings also demonstrate that TRAF2 interactions can disengage JNK signaling from NF-kappaB activation and thereby provide a new means for TRAF2 interactions to determine pathway-specific responses.
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Affiliation(s)
- R LaMonica
- Department of Medicine, Department of Molecular Genetics and Microbiology, and Molecular Cell Biology Program, State University of New York, Stony Brook, New York 11794, USA
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Mirazimi A, Svensson L. ATP is required for correct folding and disulfide bond formation of rotavirus VP7. J Virol 2000; 74:8048-52. [PMID: 10933714 PMCID: PMC112337 DOI: 10.1128/jvi.74.17.8048-8052.2000] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rotavirus is one of very few viruses that utilize the endoplasmic reticulum (ER) for assembly, and therefore it has been used as an attractive model to study ER-associated protein folding. In this study, we have examined the requirements for metabolic energy (ATP) for correct folding of the luminal and ER-associated VP7 of rotavirus. We found that VP7 rapidly misfolds in an energy-depleted milieu and is not degraded within 60 min. We also found that VP7 attained a stable minimum-energy state soon after translation in the ER. Most surprisingly, energy-misfolded VP7 could be recovered and establish correct disulfide bonds and antigenicity following a shift to an ATP-rich milieu. Using a Semliki Forest virus expression system, we observed that VP7 requires ATP and cellular, but not viral, factors for correct disulfide bond formation. Our results show for the first time that the disulfide bond formation of rotavirus VP7 is an ATP-dependent process. It has previously been shown that chaperones hydrolyze ATP during interaction with newly synthesized polypeptides and prevent nonproductive intra- and intermolecular interactions. The most reasonable explanation for the energy requirement of VP7 is thus a close interaction during folding with an ATP-dependent chaperone, such as BiP (Grp78), and possibly with protein disulfide isomerase. Taken together, our observations provide new information about folding of ER-associated proteins in general and rotavirus VP7 in particular.
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Affiliation(s)
- A Mirazimi
- Department of Virology, Swedish Institute for Infectious Disease Control, Karolinska Institute, 171 82 Solna, Sweden
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39
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Dowling W, Denisova E, LaMonica R, Mackow ER. Selective membrane permeabilization by the rotavirus VP5* protein is abrogated by mutations in an internal hydrophobic domain. J Virol 2000; 74:6368-76. [PMID: 10864647 PMCID: PMC112143 DOI: 10.1128/jvi.74.14.6368-6376.2000] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Rotavirus infectivity is dependent on the proteolytic cleavage of the VP4 spike protein into VP8* and VP5* proteins. Proteolytically activated virus, as well as expressed VP5*, permeabilizes membranes, suggesting that cleavage exposes a membrane-interactive domain of VP5* which effects rapid viral entry. The VP5* protein contains a single long hydrophobic domain (VP5*-HD, residues 385 to 404) at an internal site. In order to address the role of the VP5*-HD in permeabilizing cellular membranes, we analyzed the entry of o-nitrophenyl-beta-D-galactopyranoside (ONPG) into cells induced to express VP5* or mutated VP5* polypeptides. Following IPTG (isopropyl-beta-D-thiogalactopyranoside) induction, VP5* and VP5* truncations containing the VP5*-HD permeabilized cells to the entry and cleavage of ONPG, while VP8* and control proteins had no effect on cellular permeability. Expression of VP5* deletions containing residues 265 to 474 or 265 to 404 permeabilized cells; however, C-terminal truncations which remove the conserved GGA (residues 399 to 401) within the HD abolished membrane permeability. Site-directed mutagenesis of the VP5-HD further demonstrated a requirement for residues within the HD for VP5*-induced membrane permeability. Functional analysis of mutant VP5*s indicate that conserved glycines within the HD are required and suggest that a random coiled structure rather than the strictly hydrophobic character of the domain is required for permeability. Expressed VP5* did not alter bacterial growth kinetics or lyse bacteria following induction. Instead, VP5*-mediated size-selective membrane permeability, releasing 376-Da carboxyfluorescein but not 4-kDa fluorescein isothiocyanate-dextran from preloaded liposomes. These findings suggest that the fundamental role for VP5* in the rotavirus entry process may be to expose triple-layered particles to low [Ca](i), which uncoats the virus, rather than to effect the detergent-like lysis of early endosomal membranes.
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Affiliation(s)
- W Dowling
- Department of Medicine, SUNY at Stony Brook, Stony Brook, New York 11794-8173, USA
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40
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Nejmeddine M, Trugnan G, Sapin C, Kohli E, Svensson L, Lopez S, Cohen J. Rotavirus spike protein VP4 is present at the plasma membrane and is associated with microtubules in infected cells. J Virol 2000; 74:3313-20. [PMID: 10708448 PMCID: PMC111832 DOI: 10.1128/jvi.74.7.3313-3320.2000] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
VP4 is an unglycosylated protein of the outer layer of the capsid of rotavirus. It forms spikes that project from the outer layer of mature virions, which is mainly constituted by glycoprotein VP7. VP4 has been implicated in several important functions, such as cell attachment, penetration, hemagglutination, neutralization, virulence, and host range. Previous studies indicated that VP4 is located in the space between the periphery of the viroplasm and the outside of the endoplasmic reticulum in rotavirus-infected cells. Confocal microscopy of infected MA104 monolayers, immunostained with specific monoclonal antibodies, revealed that a significant fraction of VP4 was present at the plasma membrane early after infection. Another fraction of VP4 is cytoplasmic and colocalizes with beta-tubulin. Flow cytometry analysis confirmed that at the early stage of viral infection, VP4 was present on the plasma membrane and that its N-terminal region, the VP8* subunit, was accessible to antibodies. Biotin labeling of the infected cell surface monolayer with a cell-impermeable reagent allowed the identification of the noncleaved form of VP4 that was associated with the glycoprotein VP7. The localization of VP4 was not modified in cells transfected with a plasmid allowing the expression of a fusion protein consisting of VP4 and the green fluorescent protein. The present data suggest that VP4 reaches the plasma membrane through the microtubule network and that other viral proteins are dispensable for its targeting and transport.
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Affiliation(s)
- M Nejmeddine
- Laboratoire de Virologie et d'Immunologie Moléculaire, INRA, 78352 Jouy-en-Josas Cedex, France
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41
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Espul C, Cuello H, Martinez N, Centorbi O, O'Ryan M, Jackson L, Campos F, Matson DO. Genomic and antigenic variation among rotavirus strains circulating in a large city of Argentina. J Med Virol 2000. [DOI: 10.1002/1096-9071(200008)61:4<504::aid-jmv14>3.0.co;2-s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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42
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Coulson BS, Gentsch JR, Das BK, Bhan MK, Glass RI. Comparison of enzyme immunoassay and reverse transcriptase PCR for identification of serotype G9 rotaviruses. J Clin Microbiol 1999; 37:3187-93. [PMID: 10488175 PMCID: PMC85524 DOI: 10.1128/jcm.37.10.3187-3193.1999] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While only four globally important rotavirus G serotypes (1 to 4) have been documented, many studies suggest that serotype G9 viruses may be widely distributed and more important than previously recognized. We have evaluated 10 serotype G9 rotavirus-neutralizing monoclonal antibodies (MAbs) directed to VP7, which bound by direct enzyme immunoassay (EIA) to P1A[8], G9 rotaviruses F45, WI61, and AU32, for their ability to recognize the New Delhi G9 rotavirus 116E. Only one MAb (MAb F45:1) bound to P[11], G9 virus 116E to a high titer by EIA. This MAb was incorporated into an indirect EIA for G serotyping, which was validated with prototype cultivable human rotaviruses of G types 1 to 4 and 9. The EIA was compared with genotyping by reverse transcriptase PCR (RT-PCR) under code for the determination of the G types of rotaviruses obtained from neonates in New Delhi, India. The sensitivities of RT-PCR and EIA (after two additional freeze-thaw cycles) for the typing of G9 rotaviruses were 91 and 86%, respectively, for 24 culture-adapted rotavirus strains. The untypeable culture-adapted rotavirus samples also were unreactive with VP7 group antigen-reactive MAb 60. After two additional freeze-thaw cycles, only 26 of 42 (62%) of stools containing rotavirus typed as G9 by RT-PCR were positive for G9 rotavirus by EIA. Stools containing rotavirus untypeable by EIA contained significantly less MAb 60-reactive VP7 antigen (P = 0. 0001) than the stools containing typeable rotavirus. Thus, RT-PCR genotyping was the more sensitive method for determination of G9 type, but a serotype was readily determined in rotavirus samples containing MAb 60-reactive VP7 antigen by an EIA that incorporates MAb F45:1.
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Affiliation(s)
- B S Coulson
- Department of Microbiology and Immunology, the University of Melbourne, Parkville 3052, Victoria, Australia.
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43
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Barardi CR, Yip H, Emsile KR, Vesey G, Shanker SR, Williams KL. Flow cytometry and RT-PCR for rotavirus detection in artificially seeded oyster meat. Int J Food Microbiol 1999; 49:9-18. [PMID: 10477065 DOI: 10.1016/s0168-1605(99)00040-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A flow cytometry (FC)-based method was developed for the detection of rotavirus in oyster meat using simian rotavirus SA11 as a model. To study virus recovery, oyster meat was injected with rotavirus and the oyster extract used to infect MA104 cell monolayers. Following varying periods of infection, the cells were recovered and reacted with the monoclonal antibody M60 which is specific for the rotavirus group A serotypes 1-4 outer capsid protein, VP7, followed by a second antibody (anti mouse IgG-FITC). A FACScan FC was used to estimate the number of infected cells as well as the level of infection. To evaluate the sensitivity of the method, non-inoculated oysters were processed following the same extraction protocol and, at the end, they were seeded with the same amount of virus used for oyster inoculation. This seeded oyster extract was then used to infect MA104 cells and the number of infected cells determined using the same FC procedure. A semi-nested two-step PCR for detection of rotavirus nucleic acid was undertaken to compare the sensitivity of FC with RT-PCR. Using FC, as little as 0.02 flow cytometry units (fcu) (number of infected cells counted by FC) could be detected after 72 h of cell infection. This is a very similar limit of sensitivity to that obtained with RT-PCR. Both methods are approximately 100 times more sensitive than the plaque-forming units (pfu) assay.
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Affiliation(s)
- C R Barardi
- Departamento de Microbiologia e Parasitologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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44
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Gavrilovskaya IN, Brown EJ, Ginsberg MH, Mackow ER. Cellular entry of hantaviruses which cause hemorrhagic fever with renal syndrome is mediated by beta3 integrins. J Virol 1999; 73:3951-9. [PMID: 10196290 PMCID: PMC104173 DOI: 10.1128/jvi.73.5.3951-3959.1999] [Citation(s) in RCA: 244] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Hantaviruses replicate primarily in the vascular endothelium and cause two human diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). In this report, we demonstrate that the cellular entry of HFRS-associated hantaviruses is facilitated by specific integrins expressed on platelets, endothelial cells, and macrophages. Infection of human umbilical vein endothelial cells and Vero E6 cells by the HFRS-causing hantaviruses Hantaan (HTN), Seoul (SEO), and Puumala (PUU) is inhibited by antibodies to alphavbeta3 integrins and by the integrin ligand vitronectin. The cellular entry of HTN, SEO, and PUU viruses, but not the nonpathogenic Prospect Hill (PH) hantavirus (i.e., a virus with no associated human disease), was also mediated by introducting recombinant alphaIIbbeta3 or alphavbeta3 integrins into beta3-integrin-deficient CHO cells. In addition, PH infectivity was not inhibited by alphavbeta3-specific sera or vitronectin but was blocked by alpha5beta1-specific sera and the integrin ligand fibronectin. RGD tripeptides, which are required for many integrin-ligand interactions, are absent from all hantavirus G1 and G2 surface glycoproteins, and GRGDSP peptides did not inhibit hantavirus infectivity. Further, a mouse-human hybrid beta3 integrin-specific Fab fragment, c7E3 (ReoPro), also inhibited the infectivity of HTN, SEO, and PUU as well as HPS-associated hantaviruses, Sin Nombre (SN) and New York-1 (NY-1). These findings indicate that pathogenic HPS- and HFRS-causing hantaviruses enter cells via beta3 integrins, which are present on the surfaces of platelets, endothelial cells, and macrophages. Since beta3 integrins regulate vascular permeability and platelet function, these findings also correlate beta3 integrin usage with common elements of hantavirus pathogenesis.
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Affiliation(s)
- I N Gavrilovskaya
- Department of Medicine, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
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45
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Denisova E, Dowling W, LaMonica R, Shaw R, Scarlata S, Ruggeri F, Mackow ER. Rotavirus capsid protein VP5* permeabilizes membranes. J Virol 1999; 73:3147-53. [PMID: 10074166 PMCID: PMC104076 DOI: 10.1128/jvi.73.4.3147-3153.1999] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Proteolytic cleavage of the VP4 outer capsid spike protein into VP8* and VP5* proteins is required for rotavirus infectivity and for rotavirus-induced membrane permeability. In this study we addressed the function of the VP5* cleavage fragment in permeabilizing membranes. Expressed VP5* and truncated VP5* proteins were purified by nickel affinity chromatography and assayed for their ability to permeabilize large unilamellar vesicles (LUVs) preloaded with carboxyfluorescein (CF). VP5* and VP5* truncations, but not VP4 or VP8*, permeabilized LUVs as measured by fluorescence dequenching of released CF. Similar to virus-induced CF release, VP5*-induced CF release was concentration and temperature dependent, with a pH optimum of 7.35 at 37 degrees C, but independent of the presence of divalent cations or cholesterol. VP5*-induced permeability was completely inhibited by VP5*-specific neutralizing monoclonal antibodies (2G4, M2, or M7) which recognize conformational epitopes on VP5* but was not inhibited by VP8*-specific neutralizing antibodies. In addition, N-terminal and C-terminal VP5* truncations including residues 265 to 474 are capable of permeabilizing LUVs. These findings demonstrate that VP5* permeabilizes membranes in the absence of other rotavirus proteins and that membrane-permeabilizing VP5* truncations contain the putative fusion region within predicted virion surface domains. The ability of recombinant expressed VP5* to permeabilize membranes should permit us to functionally define requirements for VP5*-membrane interactions. These findings indicate that VP5* is a specific membrane-permeabilizing capsid protein which is likely to play a role in the cellular entry of rotaviruses.
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Affiliation(s)
- E Denisova
- Department of Medicine, SUNY at Stony Brook, Stony Brook, New York, USA
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46
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Gavrilovskaya I, LaMonica R, Fay ME, Hjelle B, Schmaljohn C, Shaw R, Mackow ER. New York 1 and Sin Nombre viruses are serotypically distinct viruses associated with hantavirus pulmonary syndrome. J Clin Microbiol 1999; 37:122-6. [PMID: 9854075 PMCID: PMC84184 DOI: 10.1128/jcm.37.1.122-126.1999] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/1998] [Accepted: 09/30/1998] [Indexed: 01/14/2023] Open
Abstract
New York 1 virus (NY-1) and Sin Nombre virus (SN) are associated with hantavirus pulmonary syndrome (HPS). NY-1 and SN are derived from unique mammalian hosts and geographic locations but have similar G1 and G2 surface proteins (93 and 97% identical, respectively). Focus reduction neutralization assays were used to define the serotypic relationship between NY-1 and SN. Sera from NY-1-positive Peromyscus leucopus neutralized NY-1 and SN at titers of >/=1/3,200 and =1/400, respectively (n = 12). Conversely, SN-specific rodent sera neutralized NY-1 and SN at titers of <1/400 and 1/6,400, respectively (n = 13). Acute-phase serum from a New York HPS patient neutralized NY-1 (1/640) but not SN (<1/20), while sera from HPS patients from the southwestern United States had 4- to >16-fold-lower neutralizing titers to NY-1 than to SN. Reference sera to Hantaan, Seoul, and Prospect Hill viruses also failed to neutralize NY-1. These results indicate that SN and NY-1 define unique hantavirus serotypes and implicate the presence of additional HPS-associated hantavirus serotypes in the Americas.
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Affiliation(s)
- I Gavrilovskaya
- The Department of Medicine, Stony Brook University, Stony Brook, New York 11794, USA
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47
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Mirazimi A, Nilsson M, Svensson L. The molecular chaperone calnexin interacts with the NSP4 enterotoxin of rotavirus in vivo and in vitro. J Virol 1998; 72:8705-9. [PMID: 9765412 PMCID: PMC110284 DOI: 10.1128/jvi.72.11.8705-8709.1998] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Calnexin is an endoplasmic reticulum (ER)-associated molecular chaperone proposed to promote folding and assembly of glycoproteins that traverse the secretory pathway in eukaryotic cells. In this study we examined if calnexin interacts with the ER-associated luminal (VP7) and transmembrane (NSP4) proteins of rotavirus. Only glycosylated NSP4 interacted with calnexin and did so in a time-dependent manner (half-life, 20 min). In vitro translation experiments programmed with gene 10 of rhesus rotavirus confirmed that calnexin recognizes only glycosylated NSP4. Castanospermine (a glucosidase I and II inhibitor) experiments established that calnexin associates only with partly deglucosylated (di- or monoglucosylated) NSP4. Furthermore, enzymatic removal of the remaining glucose residues on the N-linked glycan units was essential to disengage the NSP4-calnexin complex. Novel experiments with castanospermine revealed that glucose trimming and the calnexin-NSP4 interaction were not critical for the assembly of infectious virus.
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Affiliation(s)
- A Mirazimi
- Department of Virology, SMI/Karolinska Institute, 105 21 Stockholm, Sweden
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48
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Barardi CR, Emslie KR, Vesey G, Williams KL. Development of a rapid and sensitive quantitative assay for rotavirus based on flow cytometry. J Virol Methods 1998; 74:31-8. [PMID: 9763126 DOI: 10.1016/s0166-0934(98)00061-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A very sensitive and accurate flow cytometry (FC) based method have developed to quantitate rotavirus infection in MA104 cells. Confluent cell monolayers were infected with serial dilutions of rotavirus SA11. After infection, the cells were recovered with the aid of trypsin and then reacted with monoclonal antibody M60 (specific for the rotavirus outer capsid protein, VP7), followed by a second antibody (anti-mouse IgG-FITC). A FACScan FC was used to estimate the number of infected cells, as well as the level of infection. Viral infection was optimised by varying the concentration of trypsin used in the maintenance medium. The FC method enables many cells to be screened quickly for infectivity, and can detect low levels of virus. This method can be adapted to monitor the presence of other viruses in clinical and environmental samples without the need for prolonged periods of adaptation to growth in tissue culture.
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Affiliation(s)
- C R Barardi
- Departamento de Microbiologia e Parasitologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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49
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Shastri S, Doane AM, Gonzales J, Upadhyayula U, Bass DM. Prevalence of astroviruses in a children's hospital. J Clin Microbiol 1998; 36:2571-4. [PMID: 9705394 PMCID: PMC105164 DOI: 10.1128/jcm.36.9.2571-2574.1998] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An enzyme immunoassay for astrovirus was used to screen 357 stool samples from 267 symptomatic inpatients at a tertiary-care children's hospital. Thirty stool samples from 26 patients contained astrovirus antigen, while rotavirus was found in 34 samples and Clostridium difficile toxin was found in 40. Half of the astrovirus infections were nosocomial. Additional pathogens were identified in six of the astrovirus antigen-positive stool samples. Most (80%) of the astroviruses recovered were of serotype 1. Astrovirus infections were significantly more common than rotavirus or C. difficile infections in very young infants and in those with surgical short-bowel syndrome.
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Affiliation(s)
- S Shastri
- Department of Pediatrics and Center for Digestive Disease, Stanford University, Stanford, California 94305-5208, USA
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50
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Gavrilovskaya IN, Shepley M, Shaw R, Ginsberg MH, Mackow ER. beta3 Integrins mediate the cellular entry of hantaviruses that cause respiratory failure. Proc Natl Acad Sci U S A 1998; 95:7074-9. [PMID: 9618541 PMCID: PMC22743 DOI: 10.1073/pnas.95.12.7074] [Citation(s) in RCA: 289] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Newly emerged hantaviruses replicate primarily in the pulmonary endothelium, cause acute platelet loss, and result in hantavirus pulmonary syndrome (HPS). We now report that specific integrins expressed on platelets and endothelial cells permit the cellular entry of HPS-associated hantaviruses. Infection with HPS-associated hantaviruses, NY-1 and Sin Nombre virus (SNV), is inhibited by antibodies to beta3 integrins and by the beta3-integrin ligand, vitronectin. In contrast, infection with the nonpathogenic (no associated human disease) Prospect Hill virus was inhibited by fibronectin and beta1-specific antibodies but not by beta3-specific antibodies or vitronectin. Transfection with recombinant alphaIIb beta3 or alphav beta3 integrins rendered cells permissive to NY-1 and SNV but not Prospect Hill virus infection, indicating that alphaIIb beta3 and alphav beta3 integrins mediate the entry of NY-1 and SNV hantaviruses. Furthermore, entry is divalent cation independent, not blocked by arginine-glycine-aspartic acid peptides and still mediated by, ligand-binding defective, alphaIIb beta3-integrin mutants. Hence, NY-1 and SNV entry is independent of beta3 integrin binding to physiologic ligands. These findings implicate integrins as cellular receptors for hantaviruses and indicate that hantavirus pathogenicity correlates with integrin usage.
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Affiliation(s)
- I N Gavrilovskaya
- The Department of Medicine, Stony Brook University, HSC T17, Room 60, Stony Brook, NY 11794, USA
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