Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 329
Filtrar
1.
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
2.
Vet Microbiol ; 235: 136-142, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31282371

RESUMO

Infectious Bursal Disease Virus (IBDV) of the ITA genotype (G6) was shown to have peculiar molecular characteristics and, despite a subclinical course, aggressiveness towards lymphoid tissues after experimental infection of specific-pathogen-free (SPF) chickens. The aim of the present study was to evaluate and compare with a Classical IBDV strain, ITA IBDV distribution and persistence in various tissues (bursa of Fabricious, spleen, thymus, bone marrow, caecal tonsils, Harderian gland, kidney, liver and proventriculus), its cloacal shedding and the involvement of gut TLR-3 in duodenum tissues. The 35-day-old SPF chickens were experimentally infected and sampled up to 28 days post infection (dpi) for IBDV detection and TLR-3 quantification by qRT-PCR. The ITA IBDV strain was detected in lymphoid and most non-lymphoid tissues up to the end of the trial, with higher loads compared to the Classical IBDV. Most of those differences were found during the first 2 weeks post-infection. Notably, bone marrow and caecal tonsils presented higher viral loads until 28 dpi, allowing to speculate that these organs may serve as non-bursal lymphoid tissues supporting virus replication. Differences in relative TLR-3 gene expression between ITA IBDV-infected birds and Classical-IBDV infected ones were observed at 4, 14 and 21 dpi, being initially higher in Classical group and later in ITA group. Our results provide new insights into IBDV pathogenesis showing that IBDV of ITA genotype leads to a high and persistent viral load in lymphoid tissues and to a delayed antiviral response.


Assuntos
Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/genética , Tecido Linfoide/virologia , Doenças das Aves Domésticas/imunologia , Carga Viral , Animais , Infecções por Birnaviridae/imunologia , Medula Óssea/patologia , Medula Óssea/virologia , Galinhas , Ensaio de Imunoadsorção Enzimática , Genótipo , Vírus da Doença Infecciosa da Bursa/patogenicidade , Tonsila Palatina/virologia , Doenças das Aves Domésticas/virologia , Organismos Livres de Patógenos Específicos , Receptor 3 Toll-Like/genética , Replicação Viral
3.
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
4.
Avian Pathol ; 48(5): 486-491, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31155926

RESUMO

Bursa tissue samples from a pullet flock in New York State that was experiencing immune suppression related disease were sent to our laboratory in 2018. A very virulent infectious bursal disease virus (vvIBDV) was identified in those samples through molecular and pathogenicity studies and designated 1/chicken/USA/1054NY/18. Phylogenetic analyses of the hypervariable VP2 nucleotide sequence region indicated that this strain belonged to genogroup 3 which comprises the vvIBDV. Partial sequence data of the VP1 gene indicated this virus also had a VP1 typical of vvIBDV. While vvIBDV have previously been identified in the United States in California and Washington State, the 1054NY vvIBDV was most closely related to isolates from Ethiopia, suggesting it is a new introduction into the U.S. The 1054NY vvIBDV was used to challenge four-week old specific-pathogen-free (SPF) layer chicks where it caused 100% morbidity and 68.7% mortality within 4 days. Upon necropsy, gross pathological findings in infected SPF birds included small yellowish coloured bursas, some with haemorrhages on the serosal and mucosal surfaces. Microscopic lesions included inflammation, severe lymphocyte necrosis, atrophy of the follicles and follicular depletion of lymphocytes. RESEARCH HIGHLIGHTS A very virulent infectious bursal disease virus (vvIBDV) was detected in a pullet flock in New York state, USA. Nucleotide sequence analysis of the vvIBDV VP2 gene indicates it is not related to previous US vvIBDV isolates and appears to be a new introduction into the US. The New York vvIBDV caused 100% morbidity and 68.7% mortality in four-week-old specific-pathogen-free chicks.


Assuntos
Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/virologia , Animais , Infecções por Birnaviridae/diagnóstico , Infecções por Birnaviridae/patologia , Infecções por Birnaviridae/virologia , Galinhas , Feminino , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , New York , Filogenia , Doenças das Aves Domésticas/diagnóstico , Doenças das Aves Domésticas/patologia , Organismos Livres de Patógenos Específicos , Proteínas Estruturais Virais/genética , Virulência
5.
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
6.
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
8.
Avian Pathol ; 48(3): 245-254, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30663339

RESUMO

Infectious bursal disease virus (IBDV) is the causative agent of a highly contagious immunosuppressive disease affecting young chickens. The recently described "distinct IBDV" (dIBDV) genetic lineage encompasses a group of worldwide distributed strains that share conserved genetic characteristics in both genome segments making them unique within IBDV strains. Phenotypic characterization of these strains is scarce and limited to Asiatic and European strains collected more than 15 years ago. The present study aimed to assess the complete and comprehensive phenotypic characterization of a recently collected South American dIBDV strain (1/chicken/URY/1302/16). Genetic analyses of both partial genome segments confirmed that this strain belongs to the dIBDV genetic lineage and that it is not a reassortant. Antigenic analysis with monoclonal antibodies indicated that this strain has a particular antigenic profile, similar to that obtained in a dIBDV strain from Europe (80/GA), which differs from those previously found in the traditional classic, variant and very virulent strains. Chickens infected with the South American dIBDV strain showed subclinical infections but had a marked bursal atrophy. Further analysis using Newcastle disease virus-immunized chickens, previously infected with the South American and European dIBDV strains, demonstrated their severe immunosuppressive effect. These results indicate that dIBDV strains currently circulating in South America can severely impair the immune system of chickens, consequently affecting the local poultry industry. Our study provides new insights into the characteristics and variability of this global genetic lineage and is valuable to determine whether specific control measures are required for the dIBDV lineage. Research Highlights A South American strain of the dIBDV lineage was phenotypically characterized. The strain produced subclinical infections with a marked bursal atrophy. Infected chickens were severely immunosuppressed. The dIBDV strains are antigenically divergent from other IBDV lineages.


Assuntos
Infecções por Birnaviridae/veterinária , Galinhas/virologia , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/imunologia , Doenças das Aves Domésticas/virologia , Animais , Infecções por Birnaviridae/imunologia , Infecções por Birnaviridae/virologia , Galinhas/imunologia , Genótipo , Imunogenicidade da Vacina , Imunossupressão/veterinária , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Vírus da Doença Infecciosa da Bursa/patogenicidade , Fenótipo , Doenças das Aves Domésticas/imunologia , Virulência
9.
Arch Virol ; 164(2): 381-390, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30367293

RESUMO

Very virulent infectious bursal disease virus (vvIBDV), the cause of significant economic losses in many poultry-producing areas, has been present in Morocco since 1991. In spite of the introduction of vaccination, disease outbreaks are frequently observed. To ascertain if vaccines failure may be due to the emergence of new strains, the aim of this study was to perform for the first time the molecular characterization of vvIBDV strains circulating in Morocco by focusing on the hypervariable region (HVR) of the VP2 protein, which is frequently used for molecular epidemiology and phylogenetic studies. Field samples of haemorrhagic bursae of Fabricius were collected for molecular characterization in different parts of the country during 2016-2017 from 48 chicken flocks showing symptoms of disease. In a phylogenetic tree, nucleotide sequences containing the VP2 HVR of 13 samples that were positive for vvIBDV formed a common branch with those of vvIBDV references strains published in GenBank, but they clearly grouped into a distinct subcluster. An alignment of the deduced amino acid sequences, in addition to confirming the presence of the "signature" typical of the vvIBDV HVR, also revealed the presence of substitutions in hydrophilic loops that are known to be involved in the elicitation of neutralizing antibodies. One of these substitutions is unique to the Moroccan isolates. These results represent the first molecular characterization of vvIBDV isolates in Morocco and may indicate that one of the causes of vaccine ineffectiveness is antigenic drift.


Assuntos
Infecções por Birnaviridae/veterinária , Vírus da Doença Infecciosa da Bursa/genética , Filogenia , Doenças das Aves Domésticas/virologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Infecções por Birnaviridae/epidemiologia , Infecções por Birnaviridae/virologia , Galinhas , Vírus da Doença Infecciosa da Bursa/classificação , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Vírus da Doença Infecciosa da Bursa/patogenicidade , Dados de Sequência Molecular , Marrocos/epidemiologia , Doenças das Aves Domésticas/epidemiologia , Alinhamento de Sequência , Proteínas Virais/química , Proteínas Virais/genética , Virulência
10.
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
11.
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
12.
Avian Pathol ; 47(6): 576-584, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30086652

RESUMO

Infectious bursal disease virus (IBDV) was initially identified in the USA. For decades, these viruses were not categorized using a typing system because they were considered to be antigenically and pathogenically similar. In the 1980s, a second major serotype, serotype 2, was found in turkeys. Classification of IBDV became more complex with the discovery of antigenic variant strains called "variants" in the United States and a highly virulent strain known as "very virulent" or vvIBDV identified in Europe. To distinguish the IBDV strains identified prior to this time from the antigenic variant viruses, the term "classic viruses" was adopted. Studies over the next three decades produced a wealth of information on the antigenicity, pathogenicity and molecular structure of IBDV isolates. These data made it clear that the descriptive nomenclature used for IBDV was inadequate. For example, not all viruses identified as vvIBDV by genotyping are highly pathogenic; some have reassorted genome segments that result in lower virulence. Furthermore, variant viruses are not an antigenically homogeneous group and the term "classic virus" has been used interchangeably to describe antigenic and pathogenic types of IBDV. These and other issues make the current naming system for strains of IBDV archaic. The lack of uniform testing and standards for antigenicity and pathogenicity makes it difficult to categorize IBDV strains on a global basis. A new nomenclature that includes a genotyping system that can easily be applied worldwide is proposed and serves as a platform to begin discussions on its value to the scientific community.


Assuntos
Infecções por Birnaviridae/veterinária , Genoma Viral/genética , Vírus da Doença Infecciosa da Bursa/classificação , Doenças das Aves Domésticas/virologia , Animais , Infecções por Birnaviridae/virologia , Europa (Continente) , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Vírus da Doença Infecciosa da Bursa/patogenicidade , Filogenia , Perus , Virulência
13.
Avian Pathol ; 47(5): 520-525, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30035612

RESUMO

In the spring of 2014 infectious bursal disease (IBD) was confirmed in a Finnish layer flock exhibiting clinical signs and increased mortality. Organ and blood samples were sent for diagnosis to the Finnish Food Safety Authority Evira. IBD virus (IBDV) was detected in RT-PCR studies. Altogether hens from six layer farms associated with increased mortality (7-10%, worst case 30%) were diagnosed with IBD during 2014. Antibodies were also detected with IBD-ELISA tests in hens on two farms. Phylogenetic analysis showed that the causative agent of the 2014 IBD outbreak was a non-reassortant very virulent type IBDV. The representative virus strains from previous IBD outbreaks in 1978, 1987 and 1993 were also included in the analysis. The strains isolated in 2014 and 1993 were very similar indicating circulation of a very virulent IBDV for over 20 years in the country. In spite of the comprehensive phylogenetic analysis, the definitive origin of the viruses from 2014 and previous outbreaks remains unclear.


Assuntos
Infecções por Birnaviridae/veterinária , Galinhas , Vírus da Doença Infecciosa da Bursa/patogenicidade , Doenças das Aves Domésticas/virologia , Animais , Infecções por Birnaviridae/epidemiologia , Infecções por Birnaviridae/virologia , Finlândia/epidemiologia , Vírus da Doença Infecciosa da Bursa/genética , Filogenia , Doenças das Aves Domésticas/epidemiologia , Virulência
14.
Dev Comp Immunol ; 87: 116-123, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29886054

RESUMO

To gain insights into the role of CD3-/28.4+ intraepithelial lymphocytes-natural killer (CD3-/28.4+IEL-NK) cells during infectious bursal disease virus (IBDV) infection, characterisation of the cells was performed following infection with different strains of the virus. In vitro treatment with IL-18 or ionomycin/PMA successfully stimulated and activated the cells via a significant increase in the expression of CD69, B-Lec, CHIR-AB1 and NK-lysin. Similarly, chickens infected with the vaccine strain of IBDV also up-regulated the expression of CD69, B-Lec, CHIR-AB1 and NK-lysin in CD3-/28.4+ IEL-NK cells up to 3 days post infection (dpi) and down-regulated the expression of the inhibitory receptor B-NK at 3 dpi. On the contrary, infection with the very virulent IBDV (vvIBDV) strain lead to a reduced activation of the cells by down-regulating the expression of the CD69, CHIR-AB1 and NK-lysin especially at 1 dpi. These findings altogether demonstrate the differential activation of CD3-/28.4+IEL-NK cells in chicken following infection with the vaccine or very virulent strains of IBDV. The study therefore provides an important clue into the differential pathogenesis of IBDV infection in chicken. Further studies are however required to determine the functional importance of these findings during IBDV vaccination and infection.


Assuntos
Infecções por Birnaviridae/imunologia , Vírus da Doença Infecciosa da Bursa/imunologia , Linfócitos Intraepiteliais/imunologia , Células Matadoras Naturais/imunologia , Doenças das Aves Domésticas/imunologia , Animais , Proteínas Aviárias/genética , Proteínas Aviárias/imunologia , Infecções por Birnaviridae/genética , Infecções por Birnaviridae/virologia , Bolsa de Fabricius/imunologia , Bolsa de Fabricius/virologia , Células Cultivadas , Galinhas , Regulação da Expressão Gênica/imunologia , Interações Hospedeiro-Patógeno , Vírus da Doença Infecciosa da Bursa/classificação , Vírus da Doença Infecciosa da Bursa/patogenicidade , Linfócitos Intraepiteliais/virologia , Células Matadoras Naturais/virologia , Ativação Linfocitária/imunologia , Doenças das Aves Domésticas/genética , Doenças das Aves Domésticas/virologia , Vacinação , Vacinas/imunologia , Virulência
16.
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
17.
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
18.
Avian Pathol ; 47(3): 300-313, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29517272

RESUMO

Infectious bursal disease (IBD) is a highly contagious, immunosuppressive disease of chickens and causes substantial economic losses to the poultry industry globally. This study investigated the genetic characteristics and pathological lesions induced by IBD viruses (IBDVs) that were associated with 60 suspected outbreaks in chickens during 2015-2016 in Lusaka Province, Zambia. Nucleotide sequences of VP2 hypervariable region (VP2-HVR) (n = 38) and part of VP1 (n = 37) of Zambian IBDVs were phylogenetically analysed. Phylogenetic analysis of the VP2-HVR and VP1 revealed that most viruses (n = 31 of each genome segment) clustered with the very virulent (vv) strains. The rest of the viruses clustered with the classical strains, with two of the viruses being closely related to attenuated vaccine isolates. Two of the viruses that belonged to the vv genotype had a unique amino acid (aa) substitution Q324L whereas one virus had two unique changes, N280S and E300A in the VP2-HVR aa sequence. Although Zambian strains with a vv genotype possessed virulence marker aa within VP1 at 145T, 146D and 147N, two viruses showed unique substitutions, with one virus having 147T while the other had 147H. Pathologically, it was noted that only viruses with a vv genotype appeared to be associated with inducing pathological lesions in non-lymphoid organs (proventriculus and gizzard). Whilst documenting for the first time the presence of classical virulent IBDVs, this study demonstrates the involvement of multiple genotypes, with predominance of vvIBDVs in the epidemiology of IBD in Zambia.


Assuntos
Infecções por Birnaviridae/veterinária , Surtos de Doenças/veterinária , Vírus da Doença Infecciosa da Bursa/isolamento & purificação , Doenças das Aves Domésticas/virologia , Sequência de Aminoácidos , Animais , Infecções por Birnaviridae/epidemiologia , Infecções por Birnaviridae/virologia , Galinhas , Genótipo , Técnicas de Genotipagem/veterinária , Vírus da Doença Infecciosa da Bursa/genética , Vírus da Doença Infecciosa da Bursa/patogenicidade , Epidemiologia Molecular , Filogenia , Doenças das Aves Domésticas/epidemiologia , Alinhamento de Sequência/veterinária , Virulência , Zâmbia/epidemiologia
19.
J Virol ; 92(11)2018 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-29540593

RESUMO

Birnaviruses are unconventional members of the group of double-stranded RNA (dsRNA) viruses that are characterized by the lack of a transcriptionally active inner core. Instead, the birnaviral particles organize their genome in ribonucleoprotein complexes (RNPs) composed by dsRNA segments, the dsRNA-binding VP3 protein, and the virally encoded RNA-dependent RNA polymerase (RdRp). This and other structural features suggest that birnaviruses may follow a completely different replication program from that followed by members of the Reoviridae family, supporting the hypothesis that birnaviruses are the evolutionary link between single-stranded positive RNA (+ssRNA) and dsRNA viruses. Here we demonstrate that infectious bursal disease virus (IBDV), a prototypical member of the Birnaviridae family, hijacks endosomal membranes of infected cells through the interaction of a viral protein, VP3, with the phospholipids on the cytosolic leaflet of these compartments for replication. Employing a mutagenesis approach, we demonstrated that VP3 domain PATCH 2 (P2) mediates the association of VP3 with the endosomal membranes. To determine the role of VP3 P2 in the context of the virus replication cycle, we used avian cells stably overexpressing VP3 P2 for IBDV infection. Importantly, the intra- and extracellular virus yields, as well as the intracellular levels of VP2 viral capsid protein, were significantly diminished in cells stably overexpressing VP3 P2. Together, our results indicate that the association of VP3 with endosomes has a relevant role in the IBDV replication cycle. This report provides direct experimental evidence for membranous compartments such as endosomes being required by a dsRNA virus for its replication. The results also support the previously proposed role of birnaviruses as an evolutionary link between +ssRNA and dsRNA viruses.IMPORTANCE Infectious bursal disease (IBD; also called Gumboro disease) is an acute, highly contagious immunosuppressive disease that affects young chickens and spreads worldwide. The etiological agent of IBD is infectious bursal disease virus (IBDV). This virus destroys the central immune organ (bursa of Fabricius), resulting in immunosuppression and reduced responses of chickens to vaccines, which increase their susceptibility to other pathogens. IBDV is a member of Birnaviridae family, which comprises unconventional members of dsRNA viruses, whose replication strategy has been scarcely studied. In this report we show that IBDV hijacks the endosomes of the infected cells for establishing viral replication complexes via the association of the ribonucleoprotein complex component VP3 with the phospholipids in the cytosolic leaflet of endosomal membranes. We show that this interaction is mediated by the VP3 PATCH 2 domain and demonstrate its relevant role in the context of viral infection.


Assuntos
Endossomos/virologia , Vírus da Doença Infecciosa da Bursa/fisiologia , Fosfolipídeos/metabolismo , Proteínas Estruturais Virais/genética , Proteínas Estruturais Virais/metabolismo , Animais , Linhagem Celular , Células HeLa , Humanos , Vírus da Doença Infecciosa da Bursa/patogenicidade , Mutagênese , Domínios Proteicos , Codorniz , Proteínas Estruturais Virais/química , Replicação Viral
20.
PLoS One ; 13(2): e0192066, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29390031

RESUMO

Infectious bursal disease (IBD) is an acute, highly contagious and immunosuppressive poultry disease. IBD virus (IBDV) is the causative agent, which may lead to high morbidity and mortality rates in susceptible birds. IBDV-pathogenesis studies have focused mainly on primary lymphoid organs. It is not known if IBDV infection may modify the development of the gut associated lymphoid tissues (GALT) as well as the microbiota composition. The aim of the present study was to investigate the effects of IBDV-infection on the bursa of Fabricius (BF), caecal tonsils (CT) and caecum, and to determine the effects on the gut microbiota composition in the caecum. Commercial broiler chickens were inoculated with a very virulent (vv) strain of IBDV at 14 (Experiment 2) or 15 (Experiment 1) days post hatch (dph). Virus replication, lesion development, immune parameters including numbers of T and B lymphocytes, macrophages, as well as the gut microbiota composition were compared between groups. Rapid IBDV-replication was detected in the BF, CT and caecum. It was accompanied by histological lesions including an infiltration of heterophils. In addition a significant reduction in the total mucosal thickness of the caecum was observed in vvIBDV-infected birds compared to virus-free controls (P < 0.05). vvIBDV infection also led to an increase in T lymphocyte numbers and macrophages, as well as a decrease in the number of B lymphocytes in the lamina propria of the caecum, and in the caecal tonsils. Illumina sequencing analysis indicated that vvIBDV infection also induced changes in the abundance of Clostridium XIVa and Faecalibacterium over time. Overall, our results suggested that vvIBDV infection had a significant impact on the GALT and led to a modulation of gut microbiota composition, which may lead to a higher susceptibility of affected birds for pathogens invading through the gut.


Assuntos
Infecções por Birnaviridae/veterinária , Ceco/microbiologia , Vírus da Doença Infecciosa da Bursa/patogenicidade , Tecido Linfoide/microbiologia , Microbiota , Doenças das Aves Domésticas/patologia , Animais , Infecções por Birnaviridae/patologia , Infecções por Birnaviridae/virologia , Galinhas , Tecido Linfoide/patologia , Doenças das Aves Domésticas/virologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA