1
|
Chen T, Liu B, Chen Y, Wang X, Zhang M, Dang X, Zhao Q, Zhou EM. Development of a novel competitive ELISA based on nanobody-horseradish peroxidase fusion protein for rapid detection of antibodies against avian hepatitis E virus. Poult Sci 2022; 102:102326. [PMID: 36442305 PMCID: PMC9706638 DOI: 10.1016/j.psj.2022.102326] [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] [Received: 01/03/2022] [Revised: 11/03/2022] [Accepted: 11/03/2022] [Indexed: 11/10/2022] Open
Abstract
Avian hepatitis E virus (avian HEV) increases poultry mortality and decreases egg production, leading to huge economic losses worldwide. However, there is no effective serological test for avian HEV. Researchers previously created a testing platform using the nanobody (Nb)-horseradish peroxidase (HRP) fusion protein as an ultrasensitive probe to develop competitive ELISA (cELISA) to detect antibodies against different animal viruses. In this study, a rapid and reliable cELISA was developed to test for antibodies against avian HEV using the same platform. Six anti-avian HEV capsid protein nanobodies were selected from an immunized Bactrian camel using phage display technology. The avian HEV-Nb49-HRP fusion protein was expressed and used as a probe for developing a cELISA assay to test for avian HEV antibodies. The cut-off value of the developed cELISA was 22.0%. There was no cross-reaction with other anti-avian virus antibodies, suggesting that the cELISA had good specificity. The coefficients of variation were 0.91% to 4.21% (intra-assay) and 1.52% to 6.35% (inter-assay). Both cELISA and indirect ELISA showed a consistency of 86.7% (kappa = 0.738) for clinical chicken serum samples, and coincidence between cELISA and Western blot was 96.0% (kappa = 0.919). The epitope recognized by Nb49 was located in aa 593-604 of the avian HEV capsid protein, and the peptide (TFPS) in aa 601-604 was essential for binding. The novel cELISA is a saving cost, rapid, useful, and reliable assay for the serological investigation of avian HEV. More importantly, the peptide TFPS may be crucial to immunodominant antigen composition and protection.
Collapse
Affiliation(s)
- Tianxiang Chen
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Baoyuan Liu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China,Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Yangling, Shaanxi, China,Corresponding author:
| | - Yiyang Chen
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Xueting Wang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Meimei Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Xukun Dang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China,Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China,Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Yangling, Shaanxi, China
| |
Collapse
|
2
|
Sun P, Lin S, He S, Zhou EM, Zhao Q. Avian Hepatitis E Virus: With the Trend of Genotypes and Host Expansion. Front Microbiol 2019; 10:1696. [PMID: 31396195 PMCID: PMC6668596 DOI: 10.3389/fmicb.2019.01696] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/09/2019] [Indexed: 12/25/2022] Open
Abstract
Avian hepatitis E virus (HEV) is a single-stranded, positive-sense RNA virus with a complete genome of approximately 6.6 kb in size. To date, four major genotypes of avian HEV have been identified and classified into the Orthohepevirus B genus of the family Hepeviridae. The avian HEV associated with hepatitis-splenomegaly syndrome, big liver and spleen disease or hepatic rupture hemorrhage syndrome in chickens is genetically and antigenically related to mammalian HEV. With the increased genotypes of avian HEV identified, a broader host tropism is also notable in the epidemiological studies. Due to the lack of an efficient cell culture system, the mechanisms of avian HEV replication and pathogenesis are still poorly understood. The recent identification and characterization of animal strains of avian HEV has demonstrated the virus' ability of cross-species infection. Although it has not yet been detected in humans, the potential threat of a zoonotic HEV capable of transmission to humans needs to be taken into consideration. This review article focuses on the current knowledge regarding avian HEV in virology, epidemiology, pathogenesis, clinical presentation, transmission, diagnosis and prevention. HIGHLIGHTS - The mechanisms of avian HEV replication and pathogenesis are still poorly understood due to the lack of an efficient cell culture system.- A broader host tropism is also notable in the epidemiological studies with the increased genotypes of avian HEV identified.- The recent identification and characterization of animal strains of avian HEV has demonstrated the virus' ability of cross-species infection.- The potential threat of a zoonotic HEV capable of transmission to humans needs to be taken into consideration.
Collapse
Affiliation(s)
- Peng Sun
- School of Agriculture, Ningxia University, Yinchuan, China.,Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Yangling, China
| | - Shaoli Lin
- Division of Immunology, Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, College Park, MD, United States
| | - Shenghu He
- School of Agriculture, Ningxia University, Yinchuan, China
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Yangling, China
| | - Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Yangling, China
| |
Collapse
|
3
|
Chicken Organic Anion-Transporting Polypeptide 1A2, a Novel Avian Hepatitis E Virus (HEV) ORF2-Interacting Protein, Is Involved in Avian HEV Infection. J Virol 2019; 93:JVI.02205-18. [PMID: 30894478 DOI: 10.1128/jvi.02205-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/10/2019] [Indexed: 12/12/2022] Open
Abstract
Avian hepatitis E virus (HEV) is the main causative agent of big liver and spleen disease in chickens. Due to the absence of a highly effective cell culture system, there are few reports about the interaction between avian HEV and host cells. In this study, organic anion-transporting polypeptide 1A2 (OATP1A2) from chicken liver cells was identified to interact with ap237, a truncated avian HEV capsid protein spanning amino acids 313 to 549, by a glutathione S-transferase (GST) pulldown assay. GST pulldown and indirect enzyme-linked immunosorbent assays (ELISAs) further confirmed that the extracellular domain of OATP1A2 directly binds with ap237. The expression levels of OATP1A2 in host cells are positively correlated with the amounts of ap237 attachment and virus infection. The distribution of OATP1A2 in different tissues is consistent with avian HEV infection in vivo Finally, when the functions of OATP1A2 in cells are inhibited by its substrates or an inhibitor or blocked by ap237 or anti-OATP1A2 sera, attachment to and infection of host cells by avian HEV are significantly reduced. Collectively, these results displayed for the first time that OATP1A2 interacts with the avian HEV capsid protein and can influence viral infection in host cells. The present study provides new insight to understand the process of avian HEV infection of host cells.IMPORTANCE The process of viral infection is centered around the interaction between the virus and host cells. Due to the lack of a highly effective cell culture system in vitro, there is little understanding about the interaction between avian HEV and its host cells. In this study, a total of seven host proteins were screened in chicken liver cells by a truncated avian HEV capsid protein (ap237) in which the host protein OATP1A2 interacted with ap237. Overexpression of OATP1A2 in the cells can promote ap237 adsorption as well as avian HEV adsorption and infection of the cells. When the function of OATP1A2 in cells was inhibited by substrates or inhibitors, attachment and infection by avian HEV significantly decreased. The distribution of OATP1A2 in different chicken tissues corresponded with that in tissues during avian HEV infection. This is the first finding that OATP1A2 is involved in viral infection of host cells.
Collapse
|
4
|
Nan Y, Wu C, Zhao Q, Zhou EM. Zoonotic Hepatitis E Virus: An Ignored Risk for Public Health. Front Microbiol 2017; 8:2396. [PMID: 29255453 PMCID: PMC5723051 DOI: 10.3389/fmicb.2017.02396] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/20/2017] [Indexed: 12/27/2022] Open
Abstract
Hepatitis E virus (HEV) is a quasi-enveloped, single-stranded positive-sense RNA virus. HEV belongs to the family Hepeviridae, a family comprised of highly diverse viruses originating from various species. Since confirmation of HEV's zoonosis, HEV-induced hepatitis has been a public health concern both for developing and developed countries. Meanwhile, the demonstration of a broad host range for zoonotic HEV suggests the existence of a variety of transmission routes that could lead to human infection. Moreover, anti-HEV antibody serosurveillance worldwide demonstrates a higher than expected HEV prevalence rate that conflicts with the rarity and sporadic nature of reported acute hepatitis E cases. In recent years, chronic HEV infection, HEV-related acute hepatic failure, and extrahepatic manifestations caused by HEV infection have been frequently reported. These observations suggest a significant underestimation of the number and complexity of transmission routes previously predicted to cause HEV-related disease, with special emphasis on zoonotic HEV as a public health concern. Significant research has revealed details regarding the virology and infectivity of zoonotic HEV in both humans and animals. In this review, the discovery of HEV zoonosis, recent progress in our understanding of the zoonotic HEV host range, and classification of diverse HEV or HEV-like isolates from various hosts are reviewed in a historic context. Ultimately, this review focuses on current understanding of viral pathogenesis and cross-species transmission of zoonotic HEV. Moreover, host factors and viral determinants influencing HEV host tropism are discussed to provide new insights into HEV transmission and prevalence mechanisms.
Collapse
Affiliation(s)
- Yuchen Nan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Xianyang, China
| | - Chunyan Wu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Xianyang, China
| | - Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Xianyang, China
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnostic Technology, Ministry of Agriculture, Xianyang, China
| |
Collapse
|
5
|
Liu B, Sun Y, Chen Y, Du T, Nan Y, Wang X, Li H, Huang B, Zhang G, Zhou EM, Zhao Q. Effect of housing arrangement on fecal-oral transmission of avian hepatitis E virus in chicken flocks. BMC Vet Res 2017; 13:282. [PMID: 28882185 PMCID: PMC5590127 DOI: 10.1186/s12917-017-1203-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 08/31/2017] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Avian hepatitis E virus (HEV) infection is common in chicken flocks in China, as currently no measures exist to prevent the spread of the disease. In this study, we analyzed the effect of caged versus cage-free housing arrangements on avian HEV transmission. First, 127 serum and 110 clinical fecal samples were collected from 4 chicken flocks including the two arrangements in Shaanxi Province, China and tested for HEV antibodies and/or virus. Concurrently, 36 specific-pathogen-free chickens were divided equally into four experimental living arrangement groups, designated cage-free (Inoculated), caged (Inoculated), cage-free (Negative) and caged (Negative) groups. In caged groups, three cages contained 3 chickens each. Three chickens each from cage-free (Inoculated) and caged (Inoculated) groups (one chicken of each cage) were inoculated by cutaneous ulnar vein with the same dose of avian HEV, respectively. The cage-free (Negative) and caged (Negative) groups served as negative control. Serum and fecal samples were collected at 1 to 7 weeks post-inoculation (wpi) and liver lesions were scored at 7 wpi. RESULTS The results of serology showed that the avian HEV infection rate (54.10%) of the cage-free chickens was significantly higher than the one (12.12%) for caged chickens (P < 0.05). Also, the rate of detection of avian HEV RNA in the clinical fecal samples was significantly higher in the cage-free (22.80%, 13/57) than caged birds (5.66%, 3/53). Moreover, under experimental conditions, the infected number of uninoculated cage-free chickens (6) was significantly higher than the one for the uninoculated caged birds (2), as evidenced by seroconversion, fecal virus shedding, viremia and gross and microscopic liver lesions. CONCLUSIONS These results suggest that reduction of contact with feces as seen in the caged arrangement of housing chickens can reduce avian HEV transmission. This study provides insights for prevention and control of avian HEV infection in chicken flocks.
Collapse
Affiliation(s)
- Baoyuan Liu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Yani Sun
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Yiyang Chen
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Taofeng Du
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Yuchen Nan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Xinjie Wang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Huixia Li
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Baicheng Huang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China.,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China
| | - Gaiping Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Henan Agriculture University, Zhengzhou, Henan, 450002, China
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China. .,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China.
| | - Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, China. .,Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling, Shaanxi, China.
| |
Collapse
|
6
|
Syed SF, Sun Y, Du T, Chen Y, Liu B, Wang X, Li H, Nan Y, Zhou EM, Zhao Q. Evaluation of recombinant Chinese avian hepatitis E virus (CaHEV) ORF2 and ORF3 proteins for protection of chickens against CaHEV infection. Vaccine 2017; 35:3482-3489. [PMID: 28528763 DOI: 10.1016/j.vaccine.2017.05.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 05/02/2017] [Accepted: 05/06/2017] [Indexed: 01/01/2023]
Abstract
Avian hepatitis E virus (HEV) is the etiologic agent of big liver and spleen disease in chickens. In 2010, the Chinese avian HEV (CaHEV) strain was isolated from chickens and demonstrated to cause the decreased egg production in layer hens. No avian HEV commercial vaccine has yet been developed to prevent virus infection in China. In this study, recombinant CaHEV truncated ORF2 and complete ORF3 proteins were evaluated separately for immunoprotection of chickens against CaHEV infection. First, truncated ORF2 and complete ORF3 proteins were expressed in Escherichia coli. Next, 48 specific-pathogen-free chickens were randomly divided into three groups. One group was immunized with truncated ORF2 protein, the second group was immunized with recombinant ORF3 protein, while the third group (control) was mock-immunized with PBS. After booster immunization, chickens in all three groups were challenged intravenously with CaHEV infectious stock and assessed for viremia, fecal virus shedding, seroconversion, and gross hepatic lesions. In the ORF2 protein-immunized group, no chickens showed evidence of avian HEV infection. In the ORF3 protein-immunized group, nine chickens exhibited viremia and seven had fecal virus shedding. In the control group, all 16 chickens showed viremia and fecal virus shedding. However, the durations in chickens from the ORF3 protein group (2-4weeks) were shorter than the ones from the control group (4-8weeks). Moreover, no gross liver lesions emerged in the ORF2 protein group, while lesions observed in the ORF3 protein group were milder than in controls. Therefore, the ORF2 protein can confer complete immunoprotection against chicken CaHEV infection, while the ORF3 protein only confers partial immunoprotection.
Collapse
Affiliation(s)
- Shahid Faraz Syed
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China; Faculty of Veterinary and Animal Sciences, Lasbella University of Agriculture, Water and Marine Sciences, Uthal, Baluchistan, Pakistan
| | - Yani Sun
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - Taofeng Du
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - Yiyang Chen
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - Baoyuan Liu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - Xinjie Wang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - Huixia Li
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - Yuchen Nan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China.
| | - Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, PR China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Diagnosis, China Ministry of Agriculture, Yangling 712100, Shaanxi, PR China.
| |
Collapse
|
7
|
Nan Y, Zhang YJ. Molecular Biology and Infection of Hepatitis E Virus. Front Microbiol 2016; 7:1419. [PMID: 27656178 PMCID: PMC5013053 DOI: 10.3389/fmicb.2016.01419] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 08/26/2016] [Indexed: 12/13/2022] Open
Abstract
Hepatitis E virus (HEV) is a viral pathogen transmitted primarily via fecal-oral route. In humans, HEV mainly causes acute hepatitis and is responsible for large outbreaks of hepatitis across the world. The case fatality rate of HEV-induced hepatitis ranges from 0.5 to 3% in young adults and up to 30% in infected pregnant women. HEV strains infecting humans are classified into four genotypes. HEV strains from genotypes 3 and 4 are zoonotic, whereas those from genotypes 1 and 2 have no known animal reservoirs. Recently, notable progress has been accomplished for better understanding of HEV biology and infection, such as chronic HEV infection, in vitro cell culture system, quasi-enveloped HEV virions, functions of the HEV proteins, mechanism of HEV antagonizing host innate immunity, HEV pathogenesis and vaccine development. However, further investigation on the cross-species HEV infection, host tropism, vaccine efficacy, and HEV-specific antiviral strategy is still needed. This review mainly focuses on molecular biology and infection of HEV and offers perspective new insight of this enigmatic virus.
Collapse
Affiliation(s)
- Yuchen Nan
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F UniversityYangling, China; Molecular Virology Laboratory, VA-MD College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, College ParkMD, USA
| | - Yan-Jin Zhang
- Molecular Virology Laboratory, VA-MD College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, College Park MD, USA
| |
Collapse
|
8
|
Zhao Q, Syed SF, Zhou EM. Antigenic properties of avian hepatitis E virus capsid protein. Vet Microbiol 2015; 180:10-4. [PMID: 26340899 DOI: 10.1016/j.vetmic.2015.08.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/23/2015] [Accepted: 08/24/2015] [Indexed: 12/23/2022]
Abstract
Avian hepatitis E virus (HEV) is the main causative agent of big liver and spleen disease and hepatitis-splenomegaly syndrome in chickens, and is genetically and antigenically related to mammalian HEVs. HEV capsid protein contains immunodominant epitopes and induces a protective humoral immune response. A better understanding of the antigenic composition of this protein is critically important for the development of effective vaccine and sensitive and specific serological assays. To date, six linear antigenic domains (I-VI) have been characterized in avian HEV capsid protein and analyzed for their applications in the serological diagnosis and vaccine design. Domains I and V induce strong immune response in chickens and are common to avian, human, and swine HEVs, indicating that the shared epitopes hampering differential diagnosis of avian HEV infection. Domains III and IV are not immunodominant and elicit a weak immune response. Domain VI, located in the N-terminal region of the capsid protein, can also trigger an intense immune response, but the anti-domain VI antibodies are transient. The protection analysis showed that the truncated capsid protein containing the C-terminal 268 amino acid residues expressed by the bacterial system can provide protective immunity against avian HEV infection in chickens. However, the synthetic peptides incorporating the different linear antigenic domains (I-VI) and epitopes are non-protective. The antigenic composition of avian HEV capsid protein is altogether complex. To develop an effective vaccine and accurate serological diagnostic methods, more conformational antigenic domains or epitopes are to be characterized in detail.
Collapse
Affiliation(s)
- Qin Zhao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling 712100, Shaanxi, China
| | - Shahid Faraz Syed
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling 712100, Shaanxi, China
| | - En-Min Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Yangling 712100, Shaanxi, China; Scientific Observing and Experimental Station of Veterinary Pharmacology and Veterinary Biotechnology, Ministry of Agriculture, Yangling 712100, Shaanxi, China.
| |
Collapse
|