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Jing Z, Wu L, Pan Y, Zhang L, Zhang X, Shi D, Shi H, Chen J, Ji Z, Zhang J, Feng T, Tian J, Feng L. Rotavirus infection inhibits SLA-I expression on the cell surface by degrading β2 M via ERAD-proteasome pathway. Vet Microbiol 2024; 292:110036. [PMID: 38458048 DOI: 10.1016/j.vetmic.2024.110036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/20/2024] [Accepted: 03/01/2024] [Indexed: 03/10/2024]
Abstract
Group A Rotavirus (RVA) is a major cause of diarrhea in infants and piglets. β2-microglobulin (β2 M), encoded by the B2M gene, serves as a crucial subunit of the major histocompatibility complex class I (MHC-I) molecules. β2 M is indispensable for the transport of MHC-I to the cell membrane. MHC-I, also known as swine leukocyte antigen class I (SLA-I) in pigs, presents viral antigens to the cell surface. In this study, RVA infection down-regulated β2 M expression in both porcine intestinal epithelial cells-J2 (IPEC-J2) and MA-104 cells. RVA infection did not down-regulate the mRNA level of the B2M gene, indicating that the down-regulation of β2 M occurred on the protein level. Mechanismly, RVA infection triggered β2 M aggregation in the endoplasmic reticulum (ER) and enhanced the Lys48 (K48)-linked ubiquitination of β2 M, leading to the degradation of β2 M through ERAD-proteasome pathway. Furthermore, we found that RVA infection significantly impeded the level of SLA-I on the surface, and the overexpression of β2 M could recover its expression. In this study, our study demonstrated that RVA infection degrades β2 M via ERAD-proteasome pathway, consequently hampering SLA-I expression on the cell surface. This study would enhance the understanding of the mechanism of how RVA infection induces immune escape.
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Affiliation(s)
- Zhaoyang Jing
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Ling Wu
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Yudi Pan
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Liaoyuan Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Xin Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Da Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Hongyan Shi
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Jianfei Chen
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Zhaoyang Ji
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Jiyu Zhang
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Tingshuai Feng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China
| | - Jin Tian
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China.
| | - Li Feng
- State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Harbin, People's Republic of China.
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Muñoz-Atienza E, Díaz-Rosales P, Tafalla C. Systemic and Mucosal B and T Cell Responses Upon Mucosal Vaccination of Teleost Fish. Front Immunol 2021; 11:622377. [PMID: 33664735 PMCID: PMC7921309 DOI: 10.3389/fimmu.2020.622377] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/29/2020] [Indexed: 12/14/2022] Open
Abstract
The development of mucosal vaccines against pathogens is currently a highly explored area of research in both humans and animals. This is due to the fact that mucosal vaccines have the potential to best elicit protective responses at these mucosal surfaces, which represent the frontline of host defense, thus blocking the pathogen at its initial replication sites. However, in order to provide an efficient long-lasting protection, these mucosal vaccines have to be capable of eliciting an adequate systemic immune response in addition to local responses. In aquaculture, the need for mucosal vaccines has further practical implications, as these vaccines would avoid the individual manipulation of fish out of the water, being beneficial from both an economic and animal welfare point of view. However, how B and T cells are organized in teleost fish within these mucosal sites and how they respond to mucosally delivered antigens varies greatly when compared to mammals. For this reason, it is important to establish which mucosally delivered antigens have the capacity to induce strong and long-lasting B and T cell responses. Hence, in this review, we have summarized what is currently known regarding the adaptive immune mechanisms that are induced both locally and systemically in fish after mucosal immunization through different routes of administration including oral and nasal vaccination, anal intubation and immersion vaccination. Finally, based on the data presented, we discuss how mucosal vaccination strategies could be improved to reach significant protection levels in these species.
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Affiliation(s)
- Estefanía Muñoz-Atienza
- Fish Immunology and Pathology Laboratory, Animal Health Research Centre (CISA-INIA), Madrid, Spain
| | - Patricia Díaz-Rosales
- Fish Immunology and Pathology Laboratory, Animal Health Research Centre (CISA-INIA), Madrid, Spain
| | - Carolina Tafalla
- Fish Immunology and Pathology Laboratory, Animal Health Research Centre (CISA-INIA), Madrid, Spain
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Reslan L, Mishra N, Finianos M, Zakka K, Azakir A, Guo C, Thakka R, Dbaibo G, Lipkin WI, Zaraket H. The origins of G12P[6] rotavirus strains detected in Lebanon. J Gen Virol 2020; 102. [PMID: 33331815 DOI: 10.1099/jgv.0.001535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The G12 rotaviruses are an increasingly important cause of severe diarrhoea in infants and young children worldwide. Seven human G12P[6] rotavirus strains were detected in stool samples from children hospitalized with gastroenteritis in Lebanon during a 2011-2013 surveillance study. Complete genomes of these strains were sequenced using VirCapSeq-VERT, a capture-based high-throughput viral-sequencing method, and further characterized based on phylogenetic analyses with global RVA and vaccine strains. Based on the complete genomic analysis, all Lebanese G12 strains were found to have Wa-like genetic backbone G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1. Phylogenetically, these strains fell into two clusters where one of them might have emerged from Southeast Asian strains and the second one seems to have a mixed backbone between North American and Southeast Asian strains. Further analysis of these strains revealed high antigenic variability compared to available vaccine strains. To our knowledge, this is the first report on the complete genome-based characterization of G12P[6] emerging in Lebanon. Additional studies will provide important insights into the evolutionary dynamics of G12 rotaviruses spreading in Asia.
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Affiliation(s)
- Lina Reslan
- Center for Infectious Diseases Research, American University of Beirut, Faculty of Medicine, Beirut, Lebanon.,Department of Pediatrics and Adolescent Medicine, American University of Beirut, Faculty of Medicine, Beirut, Lebanon
| | - Nischay Mishra
- Center for Infection and the Immunity, Mailman School of Public Health, Columbia University, NY 10032, New York
| | - Marc Finianos
- Center for Infectious Diseases Research, American University of Beirut, Faculty of Medicine, Beirut, Lebanon
| | - Kimberley Zakka
- Center for Infectious Diseases Research, American University of Beirut, Faculty of Medicine, Beirut, Lebanon
| | - Amanda Azakir
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, Beirut, Lebanon.,Center for Infectious Diseases Research, American University of Beirut, Faculty of Medicine, Beirut, Lebanon
| | - Cheng Guo
- Center for Infection and the Immunity, Mailman School of Public Health, Columbia University, NY 10032, New York
| | - Riddhi Thakka
- Center for Infection and the Immunity, Mailman School of Public Health, Columbia University, NY 10032, New York
| | - Ghassan Dbaibo
- Department of Pediatrics and Adolescent Medicine, American University of Beirut, Faculty of Medicine, Beirut, Lebanon.,Center for Infectious Diseases Research, American University of Beirut, Faculty of Medicine, Beirut, Lebanon
| | - W Ian Lipkin
- Center for Infection and the Immunity, Mailman School of Public Health, Columbia University, NY 10032, New York
| | - Hassan Zaraket
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, Beirut, Lebanon.,Center for Infectious Diseases Research, American University of Beirut, Faculty of Medicine, Beirut, Lebanon
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Ogden KM, Tan Y, Akopov A, Stewart LS, McHenry R, Fonnesbeck CJ, Piya B, Carter MH, Fedorova NB, Halpin RA, Shilts MH, Edwards KM, Payne DC, Esona MD, Mijatovic-Rustempasic S, Chappell JD, Patton JT, Halasa NB, Das SR. Multiple Introductions and Antigenic Mismatch with Vaccines May Contribute to Increased Predominance of G12P[8] Rotaviruses in the United States. J Virol 2019; 93:e01476-18. [PMID: 30333170 PMCID: PMC6288334 DOI: 10.1128/jvi.01476-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 10/09/2018] [Indexed: 01/19/2023] Open
Abstract
Rotavirus is the leading global cause of diarrheal mortality for unvaccinated children under 5 years of age. The outer capsid of rotavirus virions consists of VP7 and VP4 proteins, which determine viral G and P types, respectively, and are primary targets of neutralizing antibodies. Successful vaccination depends upon generating broadly protective immune responses following exposure to rotaviruses presenting a limited number of G- and P-type antigens. Vaccine introduction resulted in decreased rotavirus disease burden but also coincided with the emergence of uncommon G and P genotypes, including G12. To gain insight into the recent predominance of G12P[8] rotaviruses in the United States, we evaluated 142 complete rotavirus genome sequences and metadata from 151 clinical specimens collected in Nashville, TN, from 2011 to 2013 through the New Vaccine Surveillance Network. Circulating G12P[8] strains were found to share many segments with other locally circulating strains but to have distinct constellations. Phylogenetic analyses of G12 sequences and their geographic sources provided evidence for multiple separate introductions of G12 segments into Nashville, TN. Antigenic epitopes of VP7 proteins of G12P[8] strains circulating in Nashville, TN, differ markedly from those of vaccine strains. Fully vaccinated children were found to be infected with G12P[8] strains more frequently than with other rotavirus genotypes. Multiple introductions and significant antigenic mismatch may in part explain the recent predominance of G12P[8] strains in the United States and emphasize the need for continued monitoring of rotavirus vaccine efficacy against emerging rotavirus genotypes.IMPORTANCE Rotavirus is an important cause of childhood diarrheal disease worldwide. Two immunodominant proteins of rotavirus, VP7 and VP4, determine G and P genotypes, respectively. Recently, G12P[8] rotaviruses have become increasingly predominant. By analyzing rotavirus genome sequences from stool specimens obtained in Nashville, TN, from 2011 to 2013 and globally circulating rotaviruses, we found evidence of multiple introductions of G12 genes into the area. Based on sequence polymorphisms, VP7 proteins of these viruses are predicted to present themselves to the immune system very differently than those of vaccine strains. Many of the sick children with G12P[8] rotavirus in their diarrheal stools also were fully vaccinated. Our findings emphasize the need for continued monitoring of circulating rotaviruses and the effectiveness of the vaccines against strains with emerging G and P genotypes.
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Affiliation(s)
- Kristen M Ogden
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Yi Tan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- J. Craig Venter Institute, Rockville, Maryland, USA
| | - Asmik Akopov
- J. Craig Venter Institute, Rockville, Maryland, USA
| | - Laura S Stewart
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Rendie McHenry
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | - Bhinnata Piya
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Maximilian H Carter
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | | | | | - Meghan H Shilts
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Kathryn M Edwards
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Daniel C Payne
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Mathew D Esona
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - James D Chappell
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - John T Patton
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Natasha B Halasa
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Suman R Das
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- J. Craig Venter Institute, Rockville, Maryland, USA
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Comparative characteristics of the VP7 and VP4 antigenic epitopes of the rotaviruses circulating in Russia (Nizhny Novgorod) and the Rotarix and RotaTeq vaccines. Arch Virol 2015; 160:1693-703. [DOI: 10.1007/s00705-015-2439-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/24/2015] [Indexed: 11/26/2022]
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Kompithra RZ, Paul A, Manoharan D, Babji S, Sarkar R, Mathew LG, Kang G. Immunogenicity of a three dose and five dose oral human rotavirus vaccine (RIX4414) schedule in south Indian infants. Vaccine 2015; 32 Suppl 1:A129-33. [PMID: 25091666 DOI: 10.1016/j.vaccine.2014.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM This study was undertaken to compare the immunogenicity of a three dose and five dose schedule of an oral live-attenuated human rotavirus vaccine, Rotarix in south Indian infants. METHOD Healthy infants (N=90), six to seven weeks of age were enrolled to receive three doses (n=45) or five doses of Rotarix vaccine (n=45) along with other scheduled vaccines, each dose separated by a four week interval. Blood samples were taken before vaccination and one month post-dose three in the Rotarix three dose group and one month post-dose five in the Rotarix five dose group; all were tested for anti-rotavirus IgA by an antibody sandwich enzyme immunoassay. RESULTS At baseline, >50% of infants had >20 units of anti-rotavirus IgA. The seroconversion rates after three and five doses were low and not significantly different in the two groups. However, among vaccine responders, children seropositive at baseline showed a much greater absolute increase in IgA antibody levels than children seronegative at baseline. CONCLUSIONS Rotarix vaccine showed low immunogenicity in south Indian children and increasing the number of doses did not increase the proportion of infants seroconverting after vaccination.
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Affiliation(s)
| | - Anu Paul
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Divya Manoharan
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Sudhir Babji
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Rajiv Sarkar
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Leni G Mathew
- Department of Paediatrics, Christian Medical College, Vellore, India
| | - Gagandeep Kang
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India.
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Hodgins DC, Chattha K, Vlasova A, Parreño V, Corbeil LB, Renukaradhya GJ, Saif LJ. Mucosal Veterinary Vaccines. Mucosal Immunol 2015. [PMCID: PMC7149859 DOI: 10.1016/b978-0-12-415847-4.00068-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Azegami T, Yuki Y, Kiyono H. Challenges in mucosal vaccines for the control of infectious diseases. Int Immunol 2014; 26:517-28. [DOI: 10.1093/intimm/dxu063] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Patel M, Glass RI, Jiang B, Santosham M, Lopman B, Parashar U. A Systematic Review of Anti-Rotavirus Serum IgA Antibody Titer as a Potential Correlate of Rotavirus Vaccine Efficacy. J Infect Dis 2013; 208:284-94. [DOI: 10.1093/infdis/jit166] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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11
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McDermid A, Le Saux N, Grudeski E, Bettinger JA, Manguiat K, Halperin SA, Macdonald L, Déry P, Embree J, Vaudry W, Booth TF. Molecular characterization of rotavirus isolates from select Canadian pediatric hospitals. BMC Infect Dis 2012; 12:306. [PMID: 23153184 PMCID: PMC3519651 DOI: 10.1186/1471-2334-12-306] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 11/07/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND We report the first multi-site rotavirus genotype analysis in Canada. Prior to this study, there was a dearth of rotavirus G and P genotyping data in Canada. Publically funded universal rotavirus vaccination in Canada started in 2011 and has been introduced by four provinces to date. Uptake of rotavirus vaccines in Canada prior to 2012 has been very limited. The aim of this study was to describe the genotypes of rotavirus strains circulating in Canada prior to widespread implementation of rotavirus vaccine by genotyping samples collected from selected paediatric hospitals. Secondly we identified rotavirus strains that differed genetically from those included in the vaccines and which could affect vaccine effectiveness. METHODS Stool specimens were collected by opportunity sampling of children with gastroenteritis who presented to emergency departments. Samples were genotyped for G (VP7) genotypes and P (VP4) genotypes by hemi-nested multiplex PCR methods. Phylogenetic analysis was carried out on Canadian G9 strains to investigate their relationship to G9 strains that have circulated in other regions of the world. RESULTS 348 samples were collected, of which 259 samples were rotavirus positive and genotyped. There were 34 rotavirus antigen immunoassay negative samples genotyped using PCR-based methods. Over the four rotavirus seasons, 174 samples were G1P[8], 45 were G3P[8], 22 were G2P[4], 13 were G9P[8], 3 were G4P[8] and 2 were G9P[4]. Sequence analysis showed that all Canadian G9 isolates are within lineage III. CONCLUSIONS Although a limited number of samples were obtained from a median of 4 centres during the 4 years of the study, it appears that currently approved rotavirus vaccines are well matched to the rotavirus genotypes identified at these hospitals. Further surveillance to monitor the emergence of rotavirus genotypes in Canada is warranted.
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Donato CM, Ch'ng LS, Boniface KF, Crawford NW, Buttery JP, Lyon M, Bishop RF, Kirkwood CD. Identification of strains of RotaTeq rotavirus vaccine in infants with gastroenteritis following routine vaccination. J Infect Dis 2012; 206:377-83. [PMID: 22615314 DOI: 10.1093/infdis/jis361] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND RotaTeq vaccine was introduced into the Australian National Immunisation Program in 2007. This study identified and characterised rotavirus strains excreted by infants who presented with symptoms of gastroenteritis following recent RotaTeq vaccination. METHODS Fecal samples (N = 61) from children who developed gastroenteritis following recent RotaTeq vaccination were forwarded to the Australian Rotavirus Surveillance Program (ARSP). RotaTeq-positive samples were genotyped and regions of the VP3, VP4, VP6, and VP7 genes were sequenced. Also, 460 rotavirus-positive ARSP routine surveillance samples were analyzed by dot-blot Northern hybridization to detect RotaTeq vaccine-derived strains circulating in the community. RESULTS Thirteen of the 61 samples collected from infants developing gastroenteritis after RotaTeq vaccination contained vaccine-derived (vd) rotavirus strains. Of these, 4 contained a vdG1P[8] strain derived by reassortment between the G1P[5] and G6P[8] parental vaccine strains. Northern hybridization analysis of 460 surveillance samples identified 3 samples that contained RotaTeq vaccine-derived strains, including 2 vdG1P[8] reassortant vaccine strains. CONCLUSIONS During replication and excretion of RotaTeq vaccine, reassortment of parental strains can occur. Shedding of RotaTeq vaccine strains in 7 of 13 infants was associated with underlying medical conditions that may have altered their immune function. The benefits of vaccination outweigh any small risk of vaccine-associated gastroenteritis.
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Affiliation(s)
- Celeste M Donato
- Enteric Virus Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Australia.
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Nakagomi T, Nakagomi O, Dove W, Doan YH, Witte D, Ngwira B, Todd S, Steele AD, Neuzil KM, Cunliffe NA. Molecular characterization of rotavirus strains detected during a clinical trial of a human rotavirus vaccine in Blantyre, Malawi. Vaccine 2012; 30 Suppl 1:A140-51. [PMID: 22520123 PMCID: PMC3982048 DOI: 10.1016/j.vaccine.2011.09.119] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 08/31/2011] [Accepted: 09/28/2011] [Indexed: 12/13/2022]
Abstract
The human, G1P[8] rotavirus vaccine (Rotarix™) significantly reduced severe rotavirus gastroenteritis episodes in a clinical trial in South Africa and Malawi, but vaccine efficacy was lower in Malawi (49.5%) than reported in South Africa (76.9%) and elsewhere. The aim of this study was to examine the molecular relationships of circulating wild-type rotaviruses detected during the clinical trial in Malawi to RIX4414 (the strain contained in Rotarix™) and to common human rotavirus strains. Of 88 rotavirus-positive, diarrhoeal stool specimens, 43 rotaviruses exhibited identifiable RNA migration patterns when examined by polyacrylamide gel electrophoresis. The genes encoding VP7, VP4, VP6 and NSP4 of 5 representative strains possessing genotypes G12P[6], G1P[8], G9P[8], and G8P[4] were sequenced. While their VP7 (G) and VP4 (P) genotype designations were confirmed, the VP6 (I) and NSP4 (E) genotypes were either I1E1 or I2E2, indicating that they were of human rotavirus origin. RNA-RNA hybridization using 21 culture-adapted strains showed that Malawian rotaviruses had a genomic RNA constellation common to either the Wa-like or the DS-1 like human rotaviruses. Overall, the Malawi strains appear similar in their genetic make-up to rotaviruses described in countries where vaccine efficacy is greater, suggesting that the lower efficacy in Malawi is unlikely to be explained by the diversity of circulating strains.
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Affiliation(s)
- Toyoko Nakagomi
- Division of Molecular Epidemiology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, and the Global Centre of Excellence, Nagasaki University, Nagasaki, Japan
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Osamu Nakagomi
- Division of Molecular Epidemiology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, and the Global Centre of Excellence, Nagasaki University, Nagasaki, Japan
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Winifred Dove
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Yen Hai Doan
- Division of Molecular Epidemiology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, and the Global Centre of Excellence, Nagasaki University, Nagasaki, Japan
| | - Desiree Witte
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Bagrey Ngwira
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Stacy Todd
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | | | | | - Nigel A Cunliffe
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
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Genetic analyses reveal differences in the VP7 and VP4 antigenic epitopes between human rotaviruses circulating in Belgium and rotaviruses in Rotarix and RotaTeq. J Clin Microbiol 2011; 50:966-76. [PMID: 22189107 DOI: 10.1128/jcm.05590-11] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Two live-attenuated rotavirus group A (RVA) vaccines, Rotarix (G1P[8]) and RotaTeq (G1-G4, P[8]), have been successfully introduced in many countries worldwide, including Belgium. The parental RVA strains used to generate the vaccines were isolated more than 20 years ago in France (G4 parental strain in RotaTeq) and the United States (all other parental strains). At present, little is known about the relationship between currently circulating human RVAs and the vaccine strains. In this study, we determined sequences for the VP7 and VP4 outer capsid proteins of representative G1P[8], G2P[4], G3P[8], G4P[8], G9P[8], and G12P[8] RVAs circulating in Belgium during 2007 to 2009. The analyses showed that multiple amino acid differences existed between the VP7 and VP4 antigenic epitopes of the vaccine viruses and the Belgian isolates, regardless of their G and P genotypes. However, the highest variability was observed among the circulating G1P[8] RVA strains and the G1 and P[8] components of both RVA vaccines. In particular, RVA strains of the P[8] lineage 4 (OP354-like) showed a significant number of amino acid differences with the P[8] VP4 of both vaccines. In addition, the circulating Belgian G3 RVA strains were found to possibly possess an extra N-linked glycosylation site compared to the G3 RVA vaccine strain of RotaTeq. These results indicate that the antigenic epitopes of RVA strains contained in the vaccines differ substantially from those of the currently circulating RVA strains in Belgium. Over time, these differences might result in selection for strains that escape the RVA neutralizing-antibody pressure induced by vaccines.
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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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16
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Donker NC, Foley M, Tamvakis DC, Bishop R, Kirkwood CD. Identification of an antibody-binding epitope on the rotavirus A non-structural protein NSP2 using phage display analysis. J Gen Virol 2011; 92:2374-2382. [PMID: 21697352 DOI: 10.1099/vir.0.032599-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The non-structural protein 2 (NSP2) of rotavirus has important roles in rotavirus replication associated with RNA binding, hydrolysis of NTPs and RNA, and helix destabilizing properties. A cell-culture assay using an NSP2-specific mAb and polyclonal antiserum to block virus replication showed a 73 and 96 % reduction in the amount of virus produced during replication, respectively. Phage display technology was used to identify the antibody-binding region on the NSP2 protein with the motif (244)T-(Y/F)-Ø-Ø-Ø-X-K-Ø-G(252), where Ø is a hydrophilic residue and X is any amino acid. This region was mapped to the three-dimensional NSP2 crystal structure to visualize the epitope. Analysis revealed identity to a region on NSP2 that mapped to a site exposed on the surface of the protein, which could possibly interfere with a functionally important region of the protein. Antibody binding to this region could disrupt the essential roles of NSP2, such as the formation of viroplasms with NSP5 or the interaction with viral RNA, thereby indicating a possible mechanism for the observed inhibition of virus replication. Genetic analysis of the putative binding region of NSP2 revealed a high level of conservation, suggesting that the region is under strict control.
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Affiliation(s)
- Nicole C Donker
- Department of Microbiology, La Trobe University, Bundoora, Victoria 3083, Australia
- Enteric Virus Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Michael Foley
- Department of Biochemistry, La Trobe University, Bundoora, Victoria 3083, Australia
| | - Debra C Tamvakis
- Department of Biochemistry, La Trobe University, Bundoora, Victoria 3083, Australia
| | - Ruth Bishop
- Enteric Virus Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Carl D Kirkwood
- Department of Microbiology, La Trobe University, Bundoora, Victoria 3083, Australia
- Enteric Virus Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia
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17
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Donker NC, Boniface K, Kirkwood CD. Phylogenetic analysis of rotavirus A NSP2 gene sequences and evidence of intragenic recombination. INFECTION GENETICS AND EVOLUTION 2011; 11:1602-7. [PMID: 21689784 DOI: 10.1016/j.meegid.2011.05.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Revised: 05/19/2011] [Accepted: 05/27/2011] [Indexed: 11/17/2022]
Abstract
The rotavirus non-structural protein NSP2 is one of the earliest and most abundant viral proteins produced during infection. This protein has multiple essential roles in the replication cycle involving RNA binding, viroplasm formation, helicase and can hydrolyse the γ-phosphate of RNA and NTPs acting as an RTPase and NTPase. In studying sequences from rotavirus strains isolated in Australia between 1984 and 2009, the NSP2 gene was seen to be highly conserved and clustered with defined NSP2 genotypes N1 and N2 according to the full genome based rotavirus classification system. Phylogenetic analysis indicated that NSP2 gene sequences isolated from Australian rotavirus strains formed four distinct lineages. Temporal variation was observed in several clusters during the 26 year period, with lineage D identified throughout the entire study period and lineage A only detected since 1999. Phylogenetic analysis and dendrograms identified NSP2 genes that exhibited reassortment between different virus VP7 genotypes, as well as a sequence from a human strain that grouped closely with the NSP2 genes of bovine rotavirus strains. This study also identified a sequence that fell between lineages and exhibited evidence of recombination, the first time that intergenic recombination has been detected in a NSP2 gene sequence. This study increases the understanding of the evolution mechanisms of NSP2 in view of improved vaccine design.
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Affiliation(s)
- Nicole C Donker
- Enteric Virus Group, Murdoch Childrens Research Institute, Royal Childrens Hospital, Parkville, Victoria 3052, Australia.
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18
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Zhou H, Guo L, Wang M, Qu J, Zhao Z, Wang J, Hung T. Prime immunization with rotavirus VLP 2/6 followed by boosting with an adenovirus expressing VP6 induces protective immunization against rotavirus in mice. Virol J 2011; 8:3. [PMID: 21205330 PMCID: PMC3024956 DOI: 10.1186/1743-422x-8-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Accepted: 01/05/2011] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Rotavirus (RV) is the main cause of severe gastroenteritis in children. An effective vaccination regime against RV can substantially reduce morbidity and mortality. Previous studies have demonstrated the efficacy of virus-like particles formed by RV VP2 and VP6 (VLP2/6), as well as that of recombinant adenovirus expressing RV VP6 (rAd), in eliciting protective immunities against RV. However, the efficacy of such prime-boost strategy, which incorporates VLP and rAd in inducing protective immunities against RV, has not been addressed. We assessed the immune effects of different regimens in mice, including rAd prime-VLP2/6 boost (rAd+VLP), VLP2/6 prime-rAd boost (VLP+rAd), rAd alone, and VLP alone. RESULTS Mice immunized with the VLP+rAd regimen elicit stronger humoral, mucosal, and cellular immune responses than those immunized with other regimens. RV challenging experiments showed that the highest reduction (92.9%) in viral shedding was achieved in the VLP+rAd group when compared with rAd+VLP (25%), VLP alone (75%), or rAd alone (40%) treatment groups. The reduction in RV shedding in mice correlated with fecal IgG (r = 0.95773, P = 0.04227) and IgA (r = 0.96137, P = 0.038663). CONCLUSIONS A VLP2/6 prime-rAd boost regimen is effective in conferring immunoprotection against RV challenge in mice. This finding may lay the groundwork for an alternative strategy in novel RV vaccine development.
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Affiliation(s)
- Hongli Zhou
- State Key Laboratory for Molecular Virology and Genetic Engineering, Institute of Pathogen Biology, Chinese Academy Medical Sciences & Peking Union Medical College, Dong Dan San Tiao, Beijing 100730, PR China
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Nakagomi O, Nakagomi T. Rotarix in Japan: Expectations and Concerns. BIOLOGICS IN THERAPY 2011; 1:4. [PMID: 24392294 PMCID: PMC3873079 DOI: 10.1007/s13554-011-0007-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Indexed: 11/30/2022]
Abstract
A live-attenuated, orally-administered, monovalent, human rotavirus vaccine, Rotarix® (GlaxoSmithKline Biologicals, Rixensart, Belgium), was licensed and launched in 2011 as the first rotavirus vaccine in Japan. The rotavirus causes a substantial disease burden with an estimated 790,000 outpatient visits, 27,000–78,000 hospitalizations, and approximately 10 deaths each year in Japan. Since a recent clinical trial showed that Rotarix was as efficacious in Japan as in other industrialized countries, it is expected that the annual number of rotavirus hospitalizations will be reduced to between 1000–3000, and that outpatient visits will be reduced to 200,000. The universal rotavirus immunization program with Rotarix was calculated to be at the threshold of being cost-effective, even from the healthcare perspective, and it was highly cost-effective from the societal perspective, assuming that Rotarix is co-administered with other childhood vaccines. While Rotarix contains only a single G1P[8] human rotavirus, the postlicensure studies in Brazil showed that Rotarix provided a 75%–85% protective efficacy against severe dehydrating diarrhea or hospitalizations due to fully-heterotypic G2P[4] strains. While postlicensure studies detected a small and finite risk of intussusception associated with the administration of Rotarix, the authors conclude that Rotarix is safe to administer to infants between 6-12 weeks of age for the first dose and by 24 weeks of age for the second dose. However, the authors strongly discourage the delayed administration of the first dose between 13-20 weeks of age, which is allowed without any warning. Given the high incidence of naturally-occurring intussusception in Japan (185 cases per 100,000 children/year among children less than 1 year of age), this should prevent pediatricians and parents from having ill-perceptions of Rotarix being associated with an increased number of temporally-associated intussusception, and fully appreciate the benefit of the rotavirus vaccine.
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Affiliation(s)
- Osamu Nakagomi
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, and the Global Center of Excellence, Nagasaki University, Nagasaki, 852-8523 Japan
| | - Toyoko Nakagomi
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, and the Global Center of Excellence, Nagasaki University, Nagasaki, 852-8523 Japan
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Arnold M, Patton JT, McDonald SM. Culturing, storage, and quantification of rotaviruses. ACTA ACUST UNITED AC 2010; Chapter 15:Unit 15C.3. [PMID: 19885940 DOI: 10.1002/9780471729259.mc15c03s15] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Group A rotaviruses (RVs) infect the young of numerous animal species and cause acute gastroenteritis. Cultivation of animal and human RVs in cells requires proteolytic activation of the viral attachment protein using trypsin. Continuous cell lines, such as rhesus monkey kidney cells, as well as primary monkey kidney cells, are routinely used for the growth and characterization of RVs. Isolation and cultivation of human RVs from clinical fecal specimens is difficult and adaptation to growth in vitro requires multiple rounds of passage in primary cells. Following growth, RV stocks can be purified by centrifugation, if required, and quantified using plaque assay or fluorescence focus assay. This unit describes easily applicable procedures for the culturing, storage, and quantification of RVs.
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Affiliation(s)
- Michelle Arnold
- Laboratory of Infectious Diseases, NIAID/NIH, Bethesda, Maryland, USA
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21
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Nakagomi T, Nakagomi O. A critical review on a globally-licensed, live, orally-administrable, monovalent human rotavirus vaccine: Rotarix. Expert Opin Biol Ther 2009; 9:1073-86. [PMID: 19591630 DOI: 10.1517/14712590903103787] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Rotavirus is the major cause of severe gastroenteritis in children worldwide, and two, live, orally-administrable vaccines are licensed globally. They are Rotarix, a monovalent, human rotavirus-based vaccine (GlaxoSmithKline), and RotaTeq, a pentavalent, bovine-human reassortant vaccine (Merck). The RIX4414 strain, a G1P[8] virus, is contained in the Rotarix vaccine. It grows efficiently in the human intestine, as evidenced by vaccine virus shedding into faeces. Efficient multiplication of RIX4414 in the intestines may play a role in stimulating immune effectors other than neutralizing antibodies that may explain the protective immunity against fully heterotypic G2P[4] strains. The protective efficacy against severe rotavirus gastroenteritis afforded by Rotarix is consistently better against strains that share with RIX4414 both G and P serotypes (i.e., G1P[8]), or only P serotype (i.e., G3P[8], G4P[8] and G9P[8]). The Rotarix vaccine is safe regarding intussusception if its first dose is administered between 6 and 12 weeks of age and the last dose by 24 weeks of age with a minimum interval of 4 weeks between the two doses. The expansion by Advisory Committee on Immunization Practices, USA, of the age limit for the first dose to age <15 weeks, and the last dose by 8 months requires close monitoring.
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Affiliation(s)
- Toyoko Nakagomi
- Nagasaki University, The Global Centre of Excellence, Graduate School of Biomedical Sciences, Department of Molecular Microbiology and Immunology, Nagasaki, Japan
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22
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Abstract
Objective: To review the pharmacology, efficacy, safety, and tolerability of RotaTeq and RotaRix, 2 rotavirus vaccines. Data Sources: English-language articles were obtained via MEDLINE (1966-August 2009) and EMBASE (1980-August 2009) searches using the key words rotavirus vaccine, epidemiology, diarrhea, intussusception, RotaShield, RotaTeq, and RotaRix. Bibliographies of selected articles were used to identify additional sources. Study Selection and Data Extraction: Available published articles reporting the results of human studies of rotavirus vaccines were reviewed for inclusion in this article. Additional information regarding clinical trials and adverse events was obtained from the manufacturer's prescribing information for each vaccine. Data Synthesis: RotaTeq is a live, attenuated human-bovine pentavalent vaccine, and RotaRix is a live, attenuated human vaccine. Both vaccines are approved for the prevention of rotavirus infection and recommended for routine immunization in healthy infants aged 14 weeks to 8 months. The vaccines differ in virologic characteristics, but clinical trials indicate similar efficacy and safety. Each vaccine is more than 70% effective in preventing any severity of rotavirus gastroenteritis and more than 98% effective in preventing severe disease through one full season of rotavirus exposure postvaccination. Efficacy begins to wane during the second season of rotavirus exposure. Post hoc analyses of clinical trials indicated an 85–100% reduction in hospitalizations and emergency department visits following vaccination. Both vaccines have been well tolerated. Fever, vomiting, and diarrhea are the most reported adverse events. Intussusception and Kawasaki syndrome have been reported, but occurrence of these events has not been shown to be significant in comparison with the background rate for each adverse event. Conclusions: RotaTeq and RotaRix are effective for the prevention of rotavirus infection in the US, Europe, and Latin America. Additional studies are needed to assess their duration of protection, worldwide efficacy, effect on the reduction of healthcare resource utilization, and adverse event monitoring.
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Affiliation(s)
- Katherine S Hale
- KATHERINE S HALE PharmD, Assistant Professor, Pharmacy Practice, Skaggs School of Pharmacy, University of Montana, Missoula, MT
| | - Sherrill J Brown
- SHERRILL J BROWN DVM PharmD BCPS, Associate Professor, Pharmacy Practice; Director, Drug Information Service, Skaggs School of Pharmacy, University of Montana
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Bondoc AJ, Jafri MA, Donnelly B, Mohanty SK, McNeal MM, Ward RL, Tiao GM. Prevention of the murine model of biliary atresia after live rotavirus vaccination of dams. J Pediatr Surg 2009; 44:1479-90. [PMID: 19635292 PMCID: PMC2748872 DOI: 10.1016/j.jpedsurg.2009.05.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 05/22/2009] [Accepted: 05/23/2009] [Indexed: 02/03/2023]
Abstract
PURPOSE Biliary atresia (BA) is a neonatal disease that results in the obliteration of the biliary tree. The murine model of BA has been established where rhesus rotavirus (RRV) infection of newborn mice leads to an obstructive cholangiopathy. We determined whether maternal postconception rotavirus vaccination could prevent the murine model of BA. MATERIALS AND METHODS Female mice were mated and injected intraperitoneally with one of the following materials: purified rotavirus strains RRV or Wa, high or low-dose Rotateq (Merck and Co Inc, Whitehouse Station, NJ) (a pentavalent rotavirus vaccine [PRV]), purified recombinant viral antigens of rotavirus (VP6) or influenza (NP), or saline. B-cell-deficient females also underwent postconception PRV injection. RESULTS Maternal vaccination with PRV improves survival of pups infected with RRV. Serum rotavirus IgG, but not IgA, levels were increased in pups delivered from dams who received RRV, Wa, PRV, or VP6, but in the case of the Wa, PRV, and VP6 groups, these antibodies were not neutralizing. Postconception injection of high-dose PRV did not improve survival of pups born to B-cell-deficient dams. CONCLUSION Maternal vaccination against RRV can prevent the rotavirus-induced murine model of BA in newborn mouse pups.
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Affiliation(s)
- Alexander J Bondoc
- Department of Pediatric and Thoracic Surgery, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229
| | - Mubeen A Jafri
- Department of Pediatric and Thoracic Surgery, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229
| | - Bryan Donnelly
- Department of Pediatric and Thoracic Surgery, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229
| | - Sujit K Mohanty
- Department of Pediatric and Thoracic Surgery, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229
| | - Monica M McNeal
- Division of Infectious Diseases Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229
| | - Richard L Ward
- Division of Infectious Diseases Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229
| | - Greg M Tiao
- Department of Pediatric and Thoracic Surgery, 3333 Burnet Avenue Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229.,Reprints and Correspondence: 3333 Burnet Avenue, Department of Pediatric and Thoracic Surgery, ML 2023, Cincinnati, OH 45229. , Telephone: 513-636-2292, Fax: 513-636-7657
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24
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Abstract
Rotavirus is a double-stranded RNA virus composed of 3 protein layers. These layers contain structural proteins (eg, VP4, VP6, and VP7) that are involved in the induction of immunity. Despite extensive research in animal models and humans, the mechanisms and effectors of protection against rotavirus after either natural infection or vaccination remain unclear. Complicating factors include the variety of immunologic responses produced after both natural infection and vaccination, and the fact that animal models do not fully mimic the human immunologic responses, even when inoculated with homologous rotaviruses. Nevertheless, it appears that neutralizing antibodies have a role in protection against rotavirus infection and disease, but that other effectors, such as non-neutralizing antibodies and T cells, have important effector properties as well. These effectors likely have overlapping functions, thus providing enhanced protection. The results of further research to elucidate the immunologic mechanism of protection will provide insight into improving the efficacy of current vaccines.
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Abstract
PURPOSE OF REVIEW Oral immunization with vaccines against intestinal infectious diseases has been extensively explored for several decades. Despite the immunologic and economic rationale behind oral immunization, only a few mucosal vaccines are available for the prevention of mucosal infections. Here, we summarize the current status of such vaccines, with a focus on intestinal infectious diseases, describe alternative approaches, and analyze advantages and difficulties encountered with a broad implementation of these vaccines. RECENT FINDINGS Due to the limited absorption from the intestinal tract and sensitivity to degradation, oral vaccines composed of killed bacteria and viruses or antigens isolated from infectious agents have not been successful. New, live-attenuated bacterial and viral or edible plant-derived vaccines, however, have been recently introduced for this purpose. Furthermore, systemic immunization with vaccines composed of bacterial polysaccharides chemically coupled to suitable protein carriers induces high levels of IgG antibodies, which may provide immunity toward Salmonella typhi, Shigella, and Escherichia coli. SUMMARY Further improvements in antigen-delivery systems, the development of adjuvants that are safe for mucosal application in humans, use of live-attenuated vaccines and microbial vectors, and production of certain vaccines in plant expression systems are likely to contribute to the broader use of oral vaccines in the future.
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