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1.
Vet Microbiol ; 239: 108458, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31767074

RESUMO

The aim of this study was to determine the antigenic relatedness of Infectious Bursal Disease Viruses (IBDVs) in the field in southern China during the period 2000-2017, as well as the antigenic relationship between the field strains and the most commonly used vaccine strains by using a virus neutralization (VN) test in vitro. The antigenic relatedness (R) value and the difference in VN titers were analyzed, and the antigenic index based on the sequences of the hypervariable region of VP2 (vVP2) of the strains was further evaluated. As a result, the R value of representative field strains showed that there were three subtypes present in the field strains examined, with 7 strains belonging to subtype 1, while strains BH11 and JS7 belonged to subtype 2 and subtype 3, respectively. The commonly used vaccine strains B87 and FW2512 belonged to subtype 1. The analysis of the VN titer differences revealed that all the 136 field strains were classified into subtype 1, except BH11 and JS7. All the field strains in subtype 1 have been divided into at least 5 subgroups, suggesting the antigenic diversity among these strains. The antigenic index based on IBDV-VP2 sequences further confirmed the antigenic differences between the three subtype strains and also the antigenic diversity among the subtype 1. The results demonstrated the antigenic diversity of field IBDVs in southern China during the years 2000-2017 and the antigenic differences between the field strains and the commonly used vaccine strains. This would indicate that the commonly used vaccines are only partially effective. These results enhance our understanding of IBDV genetic evolution and should help to develop more effective vaccines for the control of this disease in the future.


Assuntos
Antígenos Virais/imunologia , Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/fisiologia , Doenças das Aves Domésticas/virologia , Animais , Infecções por Birnaviridae/epidemiologia , Infecções por Birnaviridae/virologia , Galinhas/virologia , China/epidemiologia , Evolução Molecular , Vírus da Doença Infecciosa da Bursa/classificação , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/imunologia , Tipagem Molecular , Doenças das Aves Domésticas/epidemiologia , Vacinas Virais/imunologia
2.
Int J Mol Sci ; 20(21)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31683847

RESUMO

MicroRNAs (miRNAs) are a class of non-coding small RNAs that play important roles in the regulation of various biological processes including cell development and differentiation, apoptosis, tumorigenesis, immunoregulation and viral infections. Avian immunosuppressive diseases refer to those avian diseases caused by pathogens that target and damage the immune organs or cells of the host, increasing susceptibility to other microbial infections and the risk of failure in subsequent vaccination against other diseases. As such, once a disease with an immunosuppressive feature occurs in flocks, it would be difficult for the stakeholders to have an optimal economic income. Infectious bursal disease (IBD), avian leukemia (AL), Marek's disease (MD), chicken infectious anemia (CIA), reticuloendotheliosis (RE) and avian reovirus infection are on the top list of commonly-seen avian diseases with a feature of immunosuppression, posing an unmeasurable threat to the poultry industry across the globe. Understanding the pathogenesis of avian immunosuppressive disease is the basis for disease prevention and control. miRNAs have been shown to be involved in host response to pathogenic infections in chickens, including regulation of immunity, tumorigenesis, cell proliferation and viral replication. Here we summarize current knowledge on the roles of miRNAs in avian response to viral infection and pathogenesis of avian immunosuppressive diseases, in particular, MD, AL, IBD and RE.


Assuntos
Doenças das Aves/imunologia , Vírus da Doença Infecciosa da Bursa/imunologia , MicroRNAs/imunologia , Viroses/imunologia , Animais , Doenças das Aves/genética , Doenças das Aves/virologia , Galinhas , Tolerância Imunológica/genética , Tolerância Imunológica/imunologia , Imunidade/genética , Imunidade/imunologia , Vírus da Doença Infecciosa da Bursa/fisiologia , Doença de Marek/genética , Doença de Marek/imunologia , Doença de Marek/virologia , MicroRNAs/genética , Viroses/genética , Viroses/virologia
3.
Poult Sci ; 98(12): 6433-6444, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31504884

RESUMO

Infectious bursal disease virus (IBDV) is still a vital etiological agent in poultry farms. IBDV outbreaks occasionally occur due to the presence of very virulent, reassortment or variant strains. Vaccine immunization has played crucial roles in IBD control for decades. However, survival pressure of IBDV from the vaccine immunization also increases the reassortments of circulating viruses. In this study, an IBDV strain was isolated from several broiler farms in Henan Province, central part of China, and named IBDV HN strain. Based on the results of RT-PCR, sequencing and phylogenic analyses of VP1 and VP2 genes, the IBDV HN strain is a novel reassortment strain in the Henan region. Segment A of this strain appears to originate from the very virulent IBDV strain, while segment B comes from the other field reassortment strains. This may be the result of natural reassortant of virus circulating in the field. About 60% (6/10) of experimentally infected specific pathogen-free chickens died after 3 to 5 d post-infection with typical symptom and pathological lesions. The IBDV HN strain was prone to horizontal transmission, which poses a serious threat to the chicken industry. Further investigation on the prevalence, virulence, and evolution of HN strain IBDV will provide a foundation for the prevention and control of the disease in this region.


Assuntos
Infecções por Birnaviridae/veterinária , Bolsa de Fabricius/virologia , Galinhas , Vírus da Doença Infecciosa da Bursa/fisiologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/microbiologia , Animais , Infecções por Birnaviridae/microbiologia , China , Vírus da Doença Infecciosa da Bursa/classificação , Óvulo/virologia , Organismos Livres de Patógenos Específicos , Virulência
4.
Avian Dis ; 63(2): 275-288, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-31251527

RESUMO

Chicken dendritic cells (DCs) have been demonstrated to be susceptible to infectious bursal disease virus (IBDV), a causative agent of acute and immunosuppressed disease in young chicks known as infectious bursal disease. Further functional characterization of IBDV-infected DCs of chickens is required to provide a better understanding on the influence of the virus on chicken bone marrow-derived dendritic cells (BM-DCs) following very virulent (vv) IBDV infection. Membrane proteins of BM-DCs were extracted and the proteins were further denatured and reduced before performing labeling with isobaric tags for relative and absolute quantitation. The differential expression protein profiles were identified and quantified using liquid chromatography coupled with tandem mass spectrometry, and later validated using flow cytometry and real-time reverse transcriptase PCR. The analysis has identified 134 differentially regulated proteins from a total of 283 proteins (cutoff values of ≤0.67, ≥1.5, and ProtScore >1.3 at 95% confidence interval), which produced high-yield membrane fractions. The entry of vvIBDV into the plasma membrane of BM-DCs was observed at 3 hr postinfection by the disruption of several important protein molecule functions, namely apoptosis, RNA/DNA/protein synthesis, and transport and cellular organization, without the activation of proteins associated with signaling. At the later stage of infection, vvIBDV induced expression of several proteins, namely CD200 receptor 1-A, integrin alpha-5, HSP-90, cathepsin, lysosomal-associated membrane protein, and Ras-related proteins, which play crucial roles in signaling, apoptosis, stress response, and antigen processing as well as in secretion of danger-associated proteins. These findings collectively indicated that the chicken DCs are expressing various receptors regarded as potential targets for pathogen interaction during viral infection. Therefore, fundamental study of the interaction of DCs and IBDV will provide valuable information in understanding the role of professional antigen-presenting cells in chickens and their molecular interactions during IBDV infection and vaccination.


Assuntos
Proteínas Aviárias/genética , Infecções por Birnaviridae/veterinária , Galinhas , Células Dendríticas/imunologia , Vírus da Doença Infecciosa da Bursa/fisiologia , Doenças das Aves Domésticas/imunologia , Animais , Proteínas Aviárias/metabolismo , Infecções por Birnaviridae/genética , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/virologia , Medula Óssea , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/virologia , Proteoma , Virulência
5.
Poult Sci ; 98(11): 5307-5314, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31222288

RESUMO

Infectious bursal disease (IBD) is one of the most prevalent infectious diseases caused by IBD virus (IBDV), which results in bursal necrosis and immunosuppression that cause severe damage to the immune system in chickens. Cytokines are important mediators and regulators of both types of host responses. In the present study, layer chickens were artificially challenged with IBDV, and the differential expression of inflammatory genes was explored by using quantitative real-time PCR, which offered basic data for further study of IBDV pathogenesis. Data showed that after IBDV infection, the virus load in the bursa of Fabricius (BF) peaked at 96 h and then gradually decreased. Compared with those of the negative-infected group, the mRNA expression levels of pro-inflammatory cytokines (interleukin [IL]-1ß, IL-6, IL-7, IL-8, tumor necrosis factor [TNF]-α, transforming growth factor [TGF]-ß) and anti-inflammatory cytokine IL-10 in the infected group increased to varying degrees at 12 to 192 h, respectively. Furthermore, the IL-1ß mRNA expression peaked at 48 h; the mRNA transcript levels of IL-6, IL-8, and IL-10 were the highest at 96 h; TNF-α mRNA expression peaked at 120 h; the IL-7 mRNA expression peaked at 144 h; and the TGF-ß mRNA transcript level was the highest at 192 h. Taken together, these observations indicated that along with the change pattern of IBDV proliferation in BF, the mRNA expression of cytokines (IL-1ß, IL-6, IL-7, IL-8, IL-10, TNF-α, TGF-ß) obviously increased, and the kinetics of each of these cytokines was different. The kinetics of IL-6/IL-10 mRNA expression ratio was significantly positively correlated with that of the virus load. These results suggest that IBDV infection seriously interferes with the natural immune response mediated by inflammatory cytokines in chickens.


Assuntos
Infecções por Birnaviridae/veterinária , Galinhas , Citocinas/genética , Citocinas/imunologia , Inflamação/veterinária , Doenças das Aves Domésticas/imunologia , Animais , Proteínas Aviárias/genética , Proteínas Aviárias/imunologia , Infecções por Birnaviridae/genética , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/virologia , Vírus da Doença Infecciosa da Bursa/fisiologia , Inflamação/genética , Inflamação/imunologia , Inflamação/virologia , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/virologia , Distribuição Aleatória
6.
Br Poult Sci ; 60(5): 493-498, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31116018

RESUMO

1. Infectious bursal disease virus (IBDV) causes immunosuppression in chickens, increasing their susceptibility to other infectious diseases and resulting in vaccination failure. Here, we investigated the immune-depressing effect of IBDV on H9N2 avian influenza viral infection in the broiler chickens. 2. For this purpose, chickens were divided into four groups. In group A, chickens were inoculated with IBDV at 21 days of age and H9N2 avian influenza virus (AIV) 5 days later. Groups B and C only received AIV at 26 days of age and IBDV at 21 days, respectively. The control group (D) were inoculated with normal saline at the same times. Tissue samples from different organs were collected on the days 1, 3, 6, 9, and 12 after H9N2 infection. 3. Macroscopic observation showed IBD lesions in groups A and C, including swollen bursa with the presence of gelatinous exudates, haemorrhages in the thigh muscle, edema, and nephritis. 4. Reverse Transcription-PCR was used to study H9N2 AIV dissemination, and qRT-PCR to determine viral genome copy number in different organs. A considerable titre of AIV was found in the trachea, lungs, cecal tonsils, spleens, and feces of infected chickens. The genome copy number of the virus in the trachea and lungs of group A was significantly higher than that in group B on the first day after inoculation. But in the other days post inoculation, RT-PCR did not detect the AIV genome in group A. Although there might have been some immunosuppression in group A, IBDV could interfere with AIV replication in the chickens of this group. 5. In conclusion, we propose that pre-exposure to IBDV at 3 weeks of age reduces the replication and shedding of H9N2 in broiler chicken.


Assuntos
Infecções por Birnaviridae/veterinária , Galinhas , Vírus da Doença Infecciosa da Bursa/fisiologia , Vírus da Influenza A Subtipo H9N2/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas , Eliminação de Partículas Virais/fisiologia , Animais , Infecções por Birnaviridae/virologia , Coinfecção/veterinária , Coinfecção/virologia , Distribuição Aleatória
7.
J Virol ; 93(10)2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30842328

RESUMO

SUMOylation is a posttranslational modification that has crucial roles in diverse cellular biological pathways and in various viral life cycles. In this study, we found that the VP1 protein, the RNA-dependent RNA polymerase of avibirnavirus infectious bursal disease virus (IBDV), regulates virus replication by SUMOylation during infection. Our data demonstrated that the polymerase VP1 is efficiently modified by small ubiquitin-like modifier 1 (SUMO1) in avibirnavirus-infected cell lines. Mutation analysis showed that residues 404I and 406I within SUMO interaction motif 3 of VP1 constitute the critical site for SUMO1 modification. Protein stability assays showed that SUMO1 modification enhanced significantly the stability of polymerase VP1 by inhibiting K48-linked ubiquitination. A reverse genetic approach showed that only IBDV with I404C/T and I406C/F mutations of VP1 could be rescued successfully with decreased replication ability. Our data demonstrated that SUMO1 modification is essential to sustain the stability of polymerase VP1 during IBDV replication and provides a potential target for designing antiviral drugs targeting IBDV.IMPORTANCE SUMOylation is an extensively discussed posttranslational modification in diverse cellular biological pathways. However, there is limited understanding about SUMOylation of viral proteins of IBDV during infection. In the present study, we revealed a SUMO1 modification of VP1 protein, the RNA-dependent RNA polymerase of avibirnavirus infectious bursal disease virus (IBDV). The required site of VP1 SUMOylation comprised residues 404I and 406I of SUMO interaction motif 3, which was essential for maintaining its stability by inhibiting K48-linked ubiquitination. We also showed that IBDV with SUMOylation-deficient VP1 had decreased replication ability. These data demonstrated that the SUMOylation of IBDV VP1 played an important role in maintaining IBDV replication.


Assuntos
Vírus da Doença Infecciosa da Bursa/metabolismo , Proteína SUMO-1/metabolismo , Proteínas Estruturais Virais/metabolismo , Avibirnavirus/metabolismo , Avibirnavirus/patogenicidade , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Vírus da Doença Infecciosa da Bursa/patogenicidade , Vírus da Doença Infecciosa da Bursa/fisiologia , Processamento de Proteína Pós-Traducional , RNA Replicase/genética , Proteína SUMO-1/fisiologia , Sumoilação , Ubiquitinação , Proteínas Virais/metabolismo , Proteínas Estruturais Virais/genética , Replicação Viral/fisiologia
8.
Microb Pathog ; 129: 195-205, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30738178

RESUMO

Infectious bursal disease is one of an OIE list of notifiable diseases. Chicken is the only host that manifests clinical signs and its pathogenicity is correlated with the distribution of antigens in organs. This study was conducted to determine disease pathogenesis and virus tissue tropism by in situ PCR, immunoperoxidase staining (IPS), and HE staining. Twenty four chickens were infected with very virulent Infectious Bursal Disease Virus (vvIBDV). Fifteen chickens were kept as a control group. Infected chickens were sacrificed at hrs 2, 4, 6, 12, days 1, 2, 4, and 6 post-inoculation (pi). While, control chickens were euthanized on days 0, 1, 2, 4, and 6 pi. Different tissues were collected, fixed in 10% buffered formalin, and processed. At hr 2 pi, virus was detected in intestinal, junction of the proventriculus and gizzard, cecal tonsil, liver, kidney, and bursa of Fabricius. At hr 4 pi, virus reached spleen, and at hr 6 pi, it entered thymus. At hr 12 pi, virus concentration increased in positive tissues. The latest invaded tissue was muscle on day 1 pi. Secondary viraemia occurred during 12-24 h pi. In situ PCR was the most sensitive technique to highlight obscure points of infection in this study.


Assuntos
Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/fisiologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia , Tropismo Viral , Estruturas Animais/patologia , Estruturas Animais/virologia , Animais , Infecções por Birnaviridae/patologia , Infecções por Birnaviridae/virologia , Galinhas , Histocitoquímica , Imuno-Histoquímica , Reação em Cadeia da Polimerase , Fatores de Tempo
9.
Poult Sci ; 98(6): 2399-2404, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30690527

RESUMO

This research evaluates the effectiveness of local hatcheries in producing quality broiler day-old chicks in Ghana. A total of 600 Cobb 500 unsexed day-old broiler chicks obtained from 3 local hatcheries were raised for 6 wk with recommended starter and finisher diets from a registered source. The parameters measured included feed intake, body weights, body weight gain, feed conversion ratio, percent mortality, and haemagglutination inhibition test against Newcastle Disease virus and Infectious Bursal Disease virus (IBDv) during the first 2 wk. At the end of the study, 2 birds from each hatchery were selected and slaughtered to assess carcass parameters and primal parts including shank, neck, and head. Data were analyzed using the GLM Procedure of SAS 9.4 at P < 0.05 and LS means separated by the PDIFF of SAS. Results indicated that with the exception of the initial weight of the chicks, all other parameters were not different between the 3 hatcheries. The maternal antibody titre against IBDv was higher for all chicks but the response to Newcastle Disease virus and IBDv was relatively low in 1 hatchery. It could be concluded that the sources of chicks influenced initial chick weight but not the post-hatch performance. There is concern about the maternal antibodies levels of the chicks, which could be due to lack of appropriate and efficient vaccination of chicks.


Assuntos
Criação de Animais Domésticos/economia , Peso Corporal , Galinhas/fisiologia , Ingestão de Alimentos , Testes de Inibição da Hemaglutinação/veterinária , Doenças das Aves Domésticas/epidemiologia , Animais , Infecções por Birnaviridae/epidemiologia , Infecções por Birnaviridae/veterinária , Infecções por Birnaviridae/virologia , Galinhas/crescimento & desenvolvimento , Gana/epidemiologia , Vírus da Doença Infecciosa da Bursa/fisiologia , Doença de Newcastle/epidemiologia , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/fisiologia , Prevalência , Estudos Soroepidemiológicos
10.
Poult Sci ; 98(2): 688-694, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30239915

RESUMO

Infectious bursa disease virus (IBDV) pathogenesis is characterized by increased numbers of T cells and decreased numbers of B cells in the bursa. Currently, little is about the key factor that affects T migration into bursa. In humans, CC chemokine ligand 19 (CCL19) recruits monocytes and neutrophils and is usually involved in various inflammatory disorders. The aim of this study was to assess the roles of CCL19 in driving peripheral blood cells infiltration into bursa of Fabricius of chickens infected with IBDV. Bursal samples were collected from chickens of the infection group and the control group on day 1, 3, 5, and 7 post infection (dpi) with IBDV. The mRNA or protein levels of ccl19 and ccr7 genes in bursae were determined by real-time PCR and immunohistochemistry (IHC) methods. Moreover, an in vitro chemotaxis assay was performed to evaluate the chemotaxis ability of CCL19 and bursal total protein. The results have displayed that the mRNA levels of ccl19 were significantly increased on 1, 3, 5, and 7 dpi in the infection group. The highest value amounted to 73.4-fold of the control group. Also, the mRNA levels of CCR7, the receptor of CCL19, began to increase on 3 dpi and reached to the highest value of 206.3-fold on 5 dpi after IBDV infection. Then the gene expression of CCR7 in bursae of the infection group returned to the normal level. IHC results of CCL19 protein level accorded with the mRNA levels of CCL19, with the highest value on 5 dpi. Then, in vitro chemotaxis test demonstrated that the total bursal protein had the ability of recruiting peripheral white blood cells (PWBC) and the migration percentage was a little higher than that of the blank control with only basal medium (P < 0.05). Taken together, these data suggest that CCL19 acts as a chicken PWBC chemotactic factor and facilitate the infiltration of PWBC (especially T cells) into the bursae after IBDV infection.


Assuntos
Proteínas Aviárias/genética , Infecções por Birnaviridae/veterinária , Bolsa de Fabricius/metabolismo , Quimiocina CCL19/genética , Fatores Quimiotáticos/fisiologia , Doenças das Aves Domésticas/metabolismo , Linfócitos T/imunologia , Animais , Proteínas Aviárias/metabolismo , Infecções por Birnaviridae/metabolismo , Infecções por Birnaviridae/virologia , Quimiocina CCL19/metabolismo , Vírus da Doença Infecciosa da Bursa/fisiologia , Monócitos/metabolismo , Neutrófilos/metabolismo , Doenças das Aves Domésticas/virologia
11.
J Virol ; 93(3)2019 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-30429342

RESUMO

Ubiquitination is critical for several cellular physical processes. However, ubiquitin modification in virus replication is poorly understood. Therefore, the present study aimed to determine the presence and effect of ubiquitination on polymerase activity of viral protein 1 (VP1) of avibirnavirus. We report that the replication of avibirnavirus is regulated by ubiquitination of its VP1 protein, the RNA-dependent RNA polymerase of infectious bursal disease virus (IBDV). In vivo detection revealed the ubiquitination of VP1 protein in IBDV-infected target organs and different cells but not in purified IBDV particles. Further analysis of ubiquitination confirms that VP1 is modified by K63-linked ubiquitin chain. Point mutation screening showed that the ubiquitination site of VP1 was at the K751 residue in the C terminus. The K751 ubiquitination is independent of VP1's interaction with VP3 and eukaryotic initiation factor 4A II. Polymerase activity assays indicated that the K751 ubiquitination at the C terminus of VP1 enhanced its polymerase activity. The K751-to-R mutation of VP1 protein did not block the rescue of IBDV but decreased the replication ability of IBDV. Our data demonstrate that the ubiquitination of VP1 is crucial to regulate its polymerase activity and IBDV replication.IMPORTANCE Avibirnavirus protein VP1, the RNA-dependent RNA polymerase, is responsible for IBDV genome replication, gene expression, and assembly. However, little is known about its chemical modification relating to its polymerase activity. In this study, we revealed the molecular mechanism of ubiquitin modification of VP1 via a K63-linked ubiquitin chain during infection. Lysine (K) residue 751 at the C terminus of VP1 is the target site for ubiquitin, and its ubiquitination is independent of VP1's interaction with VP3 and eukaryotic initiation factor 4A II. The K751 ubiquitination promotes the polymerase activity of VP1 and unubiquitinated VP1 mutant IBDV significantly impairs virus replication. We conclude that VP1 is the ubiquitin-modified protein and reveal the mechanism by which VP1 promotes avibirnavirus replication.


Assuntos
Avibirnavirus/fisiologia , Infecções por Birnaviridae/virologia , Vírus da Doença Infecciosa da Bursa/fisiologia , RNA Replicase/metabolismo , Ubiquitinação , Proteínas Estruturais Virais/metabolismo , Replicação Viral , Animais , Avibirnavirus/classificação , Infecções por Birnaviridae/enzimologia , Células Cultivadas , Galinhas/virologia , Fibroblastos/metabolismo , Fibroblastos/virologia , Células HEK293 , Humanos , RNA Replicase/química , Ubiquitina/metabolismo , Proteínas Estruturais Virais/química
12.
Poult Sci ; 98(9): 3464-3470, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30481345

RESUMO

In the chicken bursa of Fabricius (BF), the interfollicular epithelium (IFE) consists of cylindrical- and cuboidal-shaped cells. Among the cylindrical-shaped epithelial cells, mucus-producing and caveolin-1 (Cav-1)-expressing cells can be distinguished. Occasionally, the cuboidal-shaped cells also express Cav-1, which suggests that they are precursors of both mucus-producing and Cav-1-expressing cells. Very virulent infectious bursal disease virus (IBDV) impedes the differentiation of Cav-1-expressing cells and shifts the differentiation of cuboidal cells towards mucus-producing cells. In control birds exclusively, the IFE surface shows a mucous membrane, but after IBDV infection, the surfaces of both IFE and FAE are also covered by a mucous membrane. After IBDV infection, the cells of FAE also produce mucus, providing evidence for cell transformation. In late postinfection (pi; 28 d pi), the Cav-1 expression returned in the IFE cells, whereas the follicle (the primary lymphoid organ) underwent atrophy. The appearance of the renewed Cav-1-positive cells is similar to that of the normal basal cell, but they randomly locate in different levels of IFE, suggesting the loss of epithelial polarity. Between days 2 and 7 pi, the Cav-1 expression in the endothelial cells of the cortico-medullary capillary web is variable, which may explain the hemorrhage in several infected birds. The IBDV infection stops the Cav-1 expression and subsequently the cholesterol efflux into the bursal lumen. In the infected birds, the high cholesterol level may further worsen the clinical syndrome of IBDV.


Assuntos
Infecções por Birnaviridae/veterinária , Bolsa de Fabricius/patologia , Galinhas , Vírus da Doença Infecciosa da Bursa/fisiologia , Doenças das Aves Domésticas/patologia , Animais , Infecções por Birnaviridae/patologia , Infecções por Birnaviridae/virologia , Bolsa de Fabricius/virologia , Epitélio/patologia , Epitélio/virologia , Feminino , Masculino , Doenças das Aves Domésticas/virologia
13.
J Vis Exp ; (140)2018 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30346401

RESUMO

Infectious bursal disease virus (IBDV) is a birnavirus of economic importance to the poultry industry. The virus infects B cells, causing morbidity, mortality, and immunosuppression in infected birds. In this study, we describe the isolation of chicken primary bursal cells from the bursa of Fabricius, the culture and infection of the cells with IBDV, and the quantification of viral replication. The addition of chicken CD40 ligand significantly increased cell proliferation fourfold over six days of culture and significantly enhanced cell viability. Two strains of IBDV, a cell-culture adapted strain, D78, and a very virulent strain, UK661, replicated well in the ex vivo cell cultures. This model will be of use in determining how cells respond to IBDV infection and will permit a reduction in the number of infected birds used in IBDV pathogenesis studies. The model can also be expanded to include other viruses and could be applied to different species of birds.


Assuntos
Infecções por Birnaviridae/veterinária , Bolsa de Fabricius/citologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/virologia , Animais , Linfócitos B/virologia , Infecções por Birnaviridae/virologia , Sobrevivência Celular , Galinhas , Vírus da Doença Infecciosa da Bursa/fisiologia , Cultura Primária de Células , Replicação Viral
14.
Vet Res ; 49(1): 89, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30208951

RESUMO

Infectious bursal disease virus (IBDV) is one of the most important immunosuppressive viral agents in poultry production. Prophylactic vaccinations of chicken flocks are the primary tool for disease control. Widely used immunoprophylaxis can, however, provide high pressure which contributes to the genetic diversification of circulating viruses, e.g. through reassortment of genome segments. We report the genetic and phenotypic characterization of a field reassortant IBDV (designated as Bpop/03) that acquired segment A from very virulent IBDV and segment B from classical attenuated D78-like IBDV. Despite the mosaic genetic make-up, the virus caused high mortality (80%) in experimentally infected SPF chickens and induced lesions typical of the acute form of IBD. The in vivo study results are in contrast with the foregoing experimental investigations in which the natural reassortants exhibited an intermediate pathotype, and underline the complex nature of IBDV virulence.


Assuntos
Infecções por Birnaviridae/veterinária , Galinhas , Genoma Viral , Vírus da Doença Infecciosa da Bursa/fisiologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/virologia , Vírus Reordenados/fisiologia , Vírus Reordenados/patogenicidade , Sequência de Aminoácidos , Animais , Infecções por Birnaviridae/virologia , Vírus da Doença Infecciosa da Bursa/genética , Filogenia , Polônia , Vírus Reordenados/genética , Virulência
15.
Microb Pathog ; 124: 216-222, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30145255

RESUMO

Infectious bursal disease virus (IBDV) is a very important small RNA virus in the family of Birnaviridae, which can cause severe immunosuppressive effects and pathological damages in young chickens. It can replicate in bursal lymphocytes and impede the growth and development of B cells, finally causing bursal lymphocytes apoptosis. Previous results have shown that protocatechuic acid (PCA) as an important phenolic compound could effectively improve the survival rate of chickens infected with IBDV. The current study aimed to explore how PCA influenced the pathogenesis of IBDV, especially lymphocyte apoptosis in the process of IBDV infection. The results showed that PCA could effectively alleviate bursal pathological changes at the early stage of IBDV invasion. Moreover, bursal lymphocyte apoptosis for tissue section samples was largely elevated by PCA by using the terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) method while the bursal lymphocyte apoptosis ratio was also increased by PCA by flow cytometry in the early stage of IBDV infection in vivo. Meanwhile, PCA could promote non-lymphocyte apoptosis in vitro. Further study displayed that the potential mechanisms mainly relied on regulation of the expressions of pro-apoptotic protein Bax and anti-apoptotic Bcl-2, thus speeding up the process of IBDV-infected cell apoptosis and preventing virus infection. Meanwhile, the results displayed that the PI3K/Akt and NF kappa B signal pathways might play an important role in promoting cell apoptosis after IBDV infection. Overall, PCA as a potent antiviral drug precursor is expected to be applied in the poultry industry as a substitute for clinical antiviral application.


Assuntos
Apoptose/efeitos dos fármacos , Infecções por Birnaviridae/tratamento farmacológico , Hidroxibenzoatos/administração & dosagem , Vírus da Doença Infecciosa da Bursa/fisiologia , Doenças das Aves Domésticas/tratamento farmacológico , Animais , Infecções por Birnaviridae/metabolismo , Infecções por Birnaviridae/fisiopatologia , Infecções por Birnaviridae/virologia , Bolsa de Fabricius/citologia , Bolsa de Fabricius/efeitos dos fármacos , Bolsa de Fabricius/metabolismo , Bolsa de Fabricius/virologia , Galinhas , Feminino , Linfócitos/citologia , Linfócitos/efeitos dos fármacos , Linfócitos/metabolismo , Masculino , NF-kappa B/genética , NF-kappa B/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Doenças das Aves Domésticas/metabolismo , Doenças das Aves Domésticas/fisiopatologia , Doenças das Aves Domésticas/virologia
16.
Vet Microbiol ; 221: 74-80, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29981711

RESUMO

Chicken melanoma differentiation-associated gene 5 (chMDA5) is a key pattern recognition receptor (PRR) that recognizes RNA viral infections and initiates an antiviral innate immune response in chickens. MicroRNAs (miRNAs) are involved in the regulation of chMDA5 to sense RNA virus infection, but how it exerts antiviral activity against infectious bursal disease virus (IBDV) infection and regulates chMDA5 in chicken cells is unclear. Thus, we measured the expression of chMDA5 in IBDV-infected DT40 cells and found it significantly increased. Overexpression of chMDA5 activated the IFN-ß and Mx promoters via IRF7-dependent pathways and inhibited replication of IBDV in DT40 cells. The opposite effect occurred after chMDA5 knockdown using siRNA. Also, gga-miR-142-5p regulated chMDA5 according to bioinformatic analysis and data from a dual-luciferase reporter system. Overexpression of gga-miR-142-5p reduced the expression of the chMDA5 protein, promoting IBDV replication, and decreased the activity of the IFN-ß and Mx promoters via an IRF7-dependent pathway; however, it had no effect on the NF-κB-dependent pathway in DT40 cells. Thus, gga-miR-142-5p is a negative regulator of chMDA5 and promotes IBDV replication in DT40 cells through an IRF7-dependent pathway.


Assuntos
Imunidade Inata , Vírus da Doença Infecciosa da Bursa/fisiologia , Fator Regulador 7 de Interferon/fisiologia , Replicação Viral/fisiologia , Animais , Linfócitos B/fisiologia , Linhagem Celular , Galinhas , Interferência de RNA
17.
J Virol ; 92(19)2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30021893

RESUMO

Infectious bursal disease virus (IBDV), a nonenveloped, double-stranded RNA (dsRNA) virus with a T=13 icosahedral capsid, has a virion assembly strategy that initiates with a precursor particle based on an internal scaffold shell similar to that of tailed double-stranded DNA (dsDNA) viruses. In IBDV-infected cells, the assembly pathway results mainly in mature virions that package four dsRNA segments, although minor viral populations ranging from zero to three dsRNA segments also form. We used cryo-electron microscopy (cryo-EM), cryo-electron tomography, and atomic force microscopy to characterize these IBDV populations. The VP3 protein was found to act as a scaffold protein by building an irregular, ∼40-Å-thick internal shell without icosahedral symmetry, which facilitates formation of a precursor particle, the procapsid. Analysis of IBDV procapsid mechanical properties indicated a VP3 layer beneath the icosahedral shell, which increased the effective capsid thickness. Whereas scaffolding proteins are discharged in tailed dsDNA viruses, VP3 is a multifunctional protein. In mature virions, VP3 is bound to the dsRNA genome, which is organized as ribonucleoprotein complexes. IBDV is an amalgam of dsRNA viral ancestors and traits from dsDNA and single-stranded RNA (ssRNA) viruses.IMPORTANCE Structural analyses highlight the constraint of virus evolution to a limited number of capsid protein folds and assembly strategies that result in a functional virion. We report the cryo-EM and cryo-electron tomography structures and the results of atomic force microscopy studies of the infectious bursal disease virus (IBDV), a double-stranded RNA virus with an icosahedral capsid. We found evidence of a new inner shell that might act as an internal scaffold during IBDV assembly. The use of an internal scaffold is reminiscent of tailed dsDNA viruses, which constitute the most successful self-replicating system on Earth. The IBDV scaffold protein is multifunctional and, after capsid maturation, is genome bound to form ribonucleoprotein complexes. IBDV encompasses numerous functional and structural characteristics of RNA and DNA viruses; we suggest that IBDV is a modern descendant of ancestral viruses and comprises different features of current viral lineages.


Assuntos
Infecções por Birnaviridae/virologia , Genoma Viral , Vírus da Doença Infecciosa da Bursa/fisiologia , RNA de Cadeia Dupla/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Estruturais Virais/metabolismo , Montagem de Vírus , Animais , Infecções por Birnaviridae/genética , Infecções por Birnaviridae/metabolismo , Capsídeo/fisiologia , Capsídeo/ultraestrutura , Células Cultivadas , Coturnix/virologia , Microscopia Crioeletrônica , Vírus da Doença Infecciosa da Bursa/ultraestrutura , Células Musculares/virologia , Proteínas de Ligação a RNA/genética , Proteínas Estruturais Virais/genética , Vírion
18.
Virus Res ; 252: 29-40, 2018 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-29777734

RESUMO

MicroRNAs (miRNAs), as post-transcriptional regulators, play important roles in the process of viral infection through inhibiting virus replication or modulating host immune response. However, the role of miRNAs in host response against infectious bursal disease virus (IBDV) infection is still unclear. In this study, we found that gga-miR-454 of the host was decreased in response to IBDV infection and that transfection of DF-1 cells with miR-454 inhibited IBDV replication via directly targeting the specific sequence of IBDV genomic segment B, while blockage of endogenous miR-454 by inhibitors enhanced virus replication. Furthermore, gga-miR-454 increased the expression of IFN-ß by targeting Suppressors of Cytokine Signaling 6 (SOCS6), enhancing the antiviral response of host cells. These findings highlight a crucial role of gga-miR-454 in host defense against IBDV infection.


Assuntos
Vírus da Doença Infecciosa da Bursa/fisiologia , MicroRNAs/genética , Proteínas Supressoras da Sinalização de Citocina/imunologia , Replicação Viral , Animais , Linhagem Celular , Galinhas/imunologia , Galinhas/virologia , Regulação da Expressão Gênica , Interações Hospedeiro-Patógeno , Imunidade Inata , Interferon beta/imunologia
19.
Arch Virol ; 163(8): 2085-2097, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29626271

RESUMO

Very virulent infectious bursal disease virus (vvIBDV) targets B lymphocytes in the bursa of Fabricius (BF), causing immunosuppression and increased mortality rates in young birds. There have been few studies on the host immune response following vvIBDV infection at different inoculum doses in chickens with different genetic backgrounds. In this study, we characterized the immune responses of specific-pathogen-free (SPF) chickens and Malaysian red jungle fowl following infection with vvIBDV strain UPM0081 at 103.8 and 106.8 times the 50% embryo infectious dose (EID50). The viral burden, histopathological changes, immune cell populations, and expression of immune-related genes were measured and compared between infected and uninfected bursa at specific intervals. The populations of KUL1+, CD3+CD4+ and CD3+CD8+ cells were significantly increased in both types of chickens at 3 dpi, and there was significant early depletion of IgM+ B cells at 1 dpi in the red jungle fowl. vvIBDV infection also induced differential expression of genes that are involved in Th1 and pro-inflammatory responses, with groups receiving the higher dose (106.8 EID50) showing earlier expression of IFNG, IL12B, IL15, IL6, CXCLi2, IL28B, and TLR3 at 1 dpi. Although both chicken types showed equal susceptibility to infection, the red jungle fowl were clinically healthier than the SPF chickens despite showing more depletion of IgM+ B cells and failure to induce IFNB activation. In conclusion, high-dose vvIBDV infection caused an intense early host immune response in the infected bursa, with depletion of IgM+ B cells, bursal lesions, and cytokine expression as a response to mitigate the severity of the infection.


Assuntos
Infecções por Birnaviridae/veterinária , Bolsa de Fabricius/imunologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/imunologia , Animais , Linfócitos B/imunologia , Linfócitos B/virologia , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/patologia , Infecções por Birnaviridae/virologia , Bolsa de Fabricius/patologia , Bolsa de Fabricius/virologia , Galinhas , Citocinas/genética , Citocinas/imunologia , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/fisiologia , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/patologia , Doenças das Aves Domésticas/virologia , Organismos Livres de Patógenos Específicos , Virulência
20.
Artigo em Inglês | MEDLINE | ID: mdl-29564226

RESUMO

Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). MicroRNAs (miRNAs) are involved in host-pathogen interactions and innate immune response to viral infection. However, the role of miRNAs in host response to IBDV infection is not clear. We report here that gga-miR-155 acts as an anti-virus host factor inhibiting IBDV replication. We found that transfection of DF-1 cells with gga-miR-155 suppressed IBDV replication, while blockage of the endogenous gga-miR-155 by inhibitors enhanced IBDV replication. Furthermore, our data showed that gga-miR-155 enhanced the expression of type I interferon in DF-1 cells post IBDV infection. Importantly, we found that gga-miR-155 enhanced type I interferon expression via targeting SOCS1 and TANK, two negative regulators of type I IFN signaling. These results indicate that gga-miR-155 plays a critical role in cell response to IBDV infection.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Interações Hospedeiro-Patógeno/fisiologia , Vírus da Doença Infecciosa da Bursa/fisiologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Interferon Tipo I/metabolismo , MicroRNAs/metabolismo , Proteína 1 Supressora da Sinalização de Citocina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Doenças das Aves/imunologia , Doenças das Aves/virologia , Infecções por Birnaviridae/imunologia , Linhagem Celular , Galinhas/imunologia , Galinhas/virologia , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Imunidade Inata , Vírus da Doença Infecciosa da Bursa/crescimento & desenvolvimento , MicroRNAs/genética , Transfecção , Replicação Viral
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