Infectious bursal disease virus affecting interferon regulatory factor 7 signaling through VP3 protein to facilitate viral replication.

Interferon regulatory factor 7 (IRF7)-mediated type I interferon antiviral response is crucial for regulating the host following viral infection in chickens. Infectious bursal disease virus (IBDV) is a double-stranded RNA virus that induces immune suppression and high mortality rates in chickens aged 3-6 weeks. Previous studies have shown that IBDV infection antagonizes the type I interferon production to facilitate viral replication in the cell, and IRF7 signaling might play an important role.

Rapid identification, pathotyping and quantification of infectious bursal disease virus by high-resolution melting curve quantitative reverse transcription PCR analysis: An innovative technology well-suited for real-time large-scale epidemiological surveillance.

With the virus continuing to evolve, very virulent IBDV (vvIBDV) and novel variant IBDV (nvIBDV) have become the predominant epidemic strains in China, exacerbated by the widespread use of attenuated vaccine strains (attIBDV), making a complex infection situation of IBDV in the field. Therefore, developing a rapid and accurate high-resolution melting curve quantitative reverse transcription PCR (HRM-qRT-PCR) for the identification and pathotyping of IBDV is crucial for clinical monitoring and disease control. Extensive data analysis and genome-screening of the three dominant IBDV pathotypes identified a specific region (nucleotides 2450-2603 in segment A) with distinct GC content as the detection target.

The complete protections induced by the oil emulsion vaccines of the novel variant infectious bursal disease viruses against the homologous challenges indicating the important roles of both VP2 and VP1 in the antigenicity and pathogenicity of the virus.

Novel variant infectious bursal disease virus (nvIBDV) is an emerging genotype (A2dB1b) that can cause severe and prolonged immunosuppression in young chickens. Despite current commercial vaccines being proven to lack complete protection against nvIBDV, it remains unclear whether the oil emulsion inactivated vaccines (OEVs) of the homologous and heterologous virus or booster immunization can provide effective protection. In this study, OEVs with two types of nvIBDV isolates QZ191002 (A-nv/B-nv) and YL160304 (A-nv/B-HLJ0504-like) were prepared and evaluated the protective effects of OEVs plus the booster immunizations with different current commercial vaccines against the challenge of nvIBDVs.

trehalose-6-phosphate synthase (tps1) promotes organ-specific virulence and fungal protection against multiple lines of host defenses.

Trehalose-6-phosphate synthase (TPS1) was identified as a virulence factor for and a promising therapeutic target. This study reveals previously unknown roles of TPS1 in evasion of host defenses during pulmonary and disseminated phases of infection. In the pulmonary infection model, TPS1-deleted () are rapidly cleared by mouse lungs whereas TPS1-sufficent WT (H99) and revertant (:) strains expand in the lungs and disseminate, causing 100% mortality.

RNA-seq reveals role of cell-cycle regulating genes in the pathogenicity of a field very virulent infectious bursal disease virus.

Infectious bursal disease virus (IBDV) infection causes highly contagious and immunosuppressive disease in poultry. The thymus, serving as the primary organ for T cell maturation and differentiation, plays an important role in the pathogenicity of IBDV in the infected chickens. However, there are no reports on the molecular pathogenesis of IBDV in the thymus currently.

Genetic and pathogenic characterizations of a naturally occurring reassortant and homologous recombinant strain of the classical infectious bursal disease virus re-emerging in chickens in southern China.

Infectious bursal disease (IBD) classical virus strain (cIBDV) can cause morbidity and mortality in young chickens with severe long-term immunosuppression. However, since the emergence and widespread prevalence of very virulent strain (vvIBDV) in China from 1991, reports of cIBDV have become rare. A novel reassortant and recombinant strain GXYL211225 (genotype A1aB1a) with segment A originating from the classical strain (A1a) and segment B from the attenuated vaccine strain (B1a) was characterized in the study.

Analysis of the global origin, evolution and transmission dynamics of the emerging novel variant IBDV (A2dB1b): The accumulation of critical aa-residue mutations and commercial trade contributes to the emergence and transmission of novel variants.

The Chinese IBDV novel variant (nvIBDV), belonging to the genotype A2dB1b, an emerging pathotype that can cause subclinical disease with severe, prolonged immunosuppression, poses a new threat to the poultry industry. The process of the global origin, evolution and transmission dynamics of nvIBDV, however, is poorly understood. In this study, phylogenetic trees, site substitutions of amino acid (aa) and highly accurate protein structure modelling, selection pressure, evolutionary and transmission dynamics of nvIBDV were analysed.

Differential Modulation of Innate Antiviral Profiles in the Intestinal Lamina Propria Cells of Chickens Infected with Infectious Bursal Disease Viruses of Different Virulence.

Infectious bursal disease virus (IBDV) is one of the most important infectious diseases of poultry around the world. Gut-associated lymphoid tissues (GALT) are the first line of defense of the host against the infection. The purpose of this study was to investigate the role of innate immune antiviral signaling triggered by Toll-like receptor 3 (TLR3), as well as macrophage activation and cytokine response in the intestinal lamina propria (ILP) cells after the oral challenge of IBDV in relation to IBDV virulence and disease pathogenesis.

The emerging naturally reassortant strain of IBDV (genotype A2dB3) having segment A from Chinese novel variant strain and segment B from HLJ 0504-like very virulent strain showed enhanced pathogenicity to three-yellow chickens.

Novel variant infectious bursal disease virus (nvIBDV) is an emerging pathotype that can cause sub-clinical disease with severe, prolonged immunosuppression in young chickens. At present, two major pathotypes, including vvIBDV and nvIBDV, are prevailing in China. In this study, we propose that the nvIBDV is a new genotype (A2dB1b) and also first isolated and characterized a nvIBDV reassortant strain YL160304 (A2dB3) with segments A and B derived, respectively, from the nvIBDV and the HLJ-0504-like vvIBDV from yellow chickens in southern China.

Rapid and visual detection of the emerging novel duck reovirus by using a specific and sensitive reverse transcription recombinase polymerase amplification method.

Duck spleen necrosis disease (DSND) caused by Novel Duck Reovirus (NDRV), is an emerging infectious disease that causes severely threaten to duck industry. Currently, the popular conventional RT-PCR technique for detecting NDRV is time consuming. So, it is essential to develop a rapid and accurate molecular diagnosis techniques of the pathogen for the purpose to effective control of the disease.

Transcriptome analysis reveals possible antitumor mechanism of Chlorella exopolysaccharide.

Microalgae, one of the most important classes of biomass producers, can produce exopolysaccharides similar to bacteria. The exopolysaccharide from Chlorella (CEPS) displays remarkable anticancer activity the mechanism of which remains to be elucidated. In this study, we analyzed the inhibitory effect of CEPS on the growth of HeLa cells.

The Full Region of N-Terminal in Polymerase of IBDV Plays an Important Role in Viral Replication and Pathogenicity: Either Partial Region or Single Amino Acid V4I Substitution Does Not Completely Lead to the Virus Attenuation to Three-Yellow Chickens.

Infectious Bursal Disease Virus (IBDV) has haunted the poultry industry with severe, prolonged immunosuppression of chickens when infected at an early age and can easily lead to other secondary infections. Understanding the pathogenic mechanisms could lead to effective prevention and control of Infectious Bursal Disease (IBD). Evidence suggests that the N-terminal domain of polymerase in segment B plays an important role, but it is not clear which part or residual is crucial for the pathogenicity.

The diagnosis and successful replication of a clinical case of Duck Spleen Necrosis Disease: An experimental co-infection of an emerging unique reovirus and Salmonella indiana reveals the roles of each of the pathogens.

Duck spleen necrosis disease (DSND) is an emerging infectious disease that causes significant economic loss in the duck industry. In 2018, a duck reovirus (named DRV/GX-Y7) and Salmonella indiana were both isolated from the spleens and livers of diseased ducks with DSND in China. The DRV/GX-Y7 strain could propagate in the Vero, LMH, DF-1 and DEF cells with obvious cytopathic effects.

Chemokine receptor CXCR3 is required for lethal brain pathology but not pathogen clearance during cryptococcal meningoencephalitis.

Cryptococcal meningoencephalitis (CM) is the major cause of infection-related neurological death, typically seen in immunocompromised patients. However, T cell-driven inflammatory response has been increasingly implicated in lethal central nervous system (CNS) immunopathology in human patients and murine models. Here, we report marked up-regulation of the chemokine receptor CXCR3 axis in human patients and mice with CM.

Serological study reveal different antigenic IBDV strains prevalent in southern China during the years 2000-2017 and also the antigenic differences between the field strains and the commonly used vaccine strains.

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.

Antigenicity characterization of four representative natural reassortment IBDVs isolated from commercial three-yellow chickens from Southern China reveals different subtypes co-prevalent in the field.

The antigenic relationships between the natural reassortment field strains of infectious bursal disease virus (IBDV), and between the field strains and the vaccine strains are poorly understood. In the present study, the antigenicity of four representative natural reassortment IBDV isolates designated JS7, GD10111, NN1005 and NN1172 from southern China during the years 2005-2011 and their antigenic relationship with the most commonly used vaccine strain B87 were investigated in vivo. For this purpose, cross-challenge studies were performed on 28-day-old birds, which were 2 weeks post-vaccination by oil-emulsion vaccines (OEVs) prepared from the four field viruses and B87, respectively.

Differential Regulation of chTLR3 by Infectious Bursal Disease Viruses with Different Virulence In Vitro and In Vivo.

Toll-like receptor 3 (TLR3) is one of the TLRs whose ligand is double-stranded RNA (dsRNA). Infectious bursal disease virus (IBDV) is a dsRNA virus that could be recognized by TLR3. The purpose of this study was to determine the role of the virulence of IBDV on the expression of chicken TLR3 (chTLR3).

Role of naturally occurring genome segment reassortment in the pathogenicity of IBDV field isolates in Three-Yellow chickens.

Reassortment among genome segments of infectious bursal disease virus (IBDV) field isolates was reported frequently worldwide, however the pathogenicity of the reassortant field IBDV is poorly understood. In this paper, a pathogenicity study on four representative IBDV field strains isolated from Southern China between 2005 and 2011 was conducted. Twenty-eight-day-old Three-Yellow chickens were divided into four groups and were inoculated intraocularly with one of the four field IBDV strains, namely NN1172, NN1005, GD10111 and JS7, respectively.

Cryptococcal heat shock protein 70 homolog Ssa1 contributes to pulmonary expansion of Cryptococcus neoformans during the afferent phase of the immune response by promoting macrophage M2 polarization.

Numerous virulence factors expressed by Cryptococcus neoformans modulate host defenses by promoting nonprotective Th2-biased adaptive immune responses. Prior studies demonstrate that the heat shock protein 70 homolog, Ssa1, significantly contributes to serotype D C. neoformans virulence through the induction of laccase, a Th2-skewing and CNS tropic factor.

Molecular epidemiology studies on partial sequences of both genome segments reveal that reassortant infectious bursal disease viruses were dominantly prevalent in southern China during 2000-2012.

A molecular epidemiology study of infectious bursal disease viruses (IBDVs) isolated from seven provinces in southern China during the years 2000-2012 was performed based on partial sequences of genome segments A and B, namely the hypervariable region of the A-VP2 gene (A-vVP2) and the b fragment of VP1 gene (B-VP1b) from a total of 91 field isolates. Sequence analysis based on vVP2 revealed that 72 out of 91 isolates had the same characteristic amino acid (aa) sequences as vvIBDV. The mutation of D212N in A-vVP2 has become prevalent in the recent isolates.

Virulence factors identified by Cryptococcus neoformans mutant screen differentially modulate lung immune responses and brain dissemination.

Deletions of cryptococcal PIK1, RUB1, and ENA1 genes independently rendered defects in yeast survival in human CSF and within macrophages. We evaluated virulence potential of these genes by comparing wild-type Cryptococcus neoformans strain H99 with deletant and complement strains in a BALB/c mouse model of pulmonary infection. Survival of infected mice; pulmonary cryptococcal growth and pathology; immunological parameters; dissemination kinetics; and CNS pathology were examined.

Molecular epidemiology of infectious bursal disease viruses isolated from Southern China during the years 2000-2010.

We performed a molecular epidemiology study of infectious bursal disease virus (IBDV) from six provinces in southern China by analyzing IBDVs isolated during the years 2000-2010. Sequence analysis of hypervariable regions of the VP2 gene (vVP2) in the genome of these isolates revealed that the majority of these viruses (45/59) were characterized as vv (very virulent) IBDV genotype, 12 out of 59 isolates were avirulent IBDV genotype and two from Guangxi were intermediate IBDV genotype. Phylogenetic analysis revealed that 45 vvIBDV genotype isolates have divided into five groups, all displaying strong divergence from the currently used vaccine strains.

[Molecular epidemiology of infectious bursal disease virus in Guangxi during the period of 2000 to 2007].

Tissue samples of Fabricius' bursa collected from Nanning, Yulin, Beihai and Wuzhou in the provinces of Guangxi in China during the years of 2000-2007, were detected by a established reverse transcriptase polymerase chain reaction (RT-PCR) technique for IBDV. Viral isolation was performed on the positive samples by chicken embryo inoculation via chorio-allantoic membrane (CAM). Results showed that 27 isolates of IBDV were obtained.