Differences in Pathogenicity and Vaccine Resistance Discovered between Two Epidemic Strains of Marek's Disease Virus in China.

Despite highly effective vaccines, Marek's disease (MD) causes great economic loss to the poultry industry annually, largely due to the continuous emergence of new MD virus (MDV) strains. To explore the pathogenic characteristics of newly emerged MDV strains, we selected two strains (AH/1807 and DH/18) with clinically different pathotypes. We studied each strain's infection process and pathogenicity and observed differences in immunosuppression and vaccine resistance. Specific pathogen-free chickens, unvaccinated or vaccinated with CVI988, were challenged with AH/1807 or DH/18. Both infections induced MD damage; however, differences were observed in terms of mortality (AH/1807: 77.8%, DH/18: 50%) and tumor rates (AH/1807: 50%, DH/18: 33.3%). The immune protection indices of the vaccine also differed (AH/1807: 94.1, DH/18: 61.1). Additionally, while both strains caused interferon-ß and interferon-γ expression to decline, DH/18 infection caused stronger immunosuppression than AH/1807. This inhibition persisted even after vaccination, leading to increased replication of DH/18 that ultimately broke through vaccine immune protection. These results indicate that both strains have different characteristics, and that strains such as DH/18, which cause weaker pathogenic damage but can break through vaccine immune protection, require further attention. Our findings increase the understanding of the differences between epidemic strains and factors underlying MD vaccination failure in China.

An efficient TILLING platform for cultivated tobacco.

Targeting-induced local lesions in genomes (TILLING) is a powerful reverse-genetics tool that enables high-throughput screening of genomic variations in plants. Although TILLING has been developed for many diploid plants, the technology has been used in very few polyploid species due to their genomic complexity. Here, we established an efficient capillary electrophoresis-based TILLING platform for allotetraploid cultivated tobacco (Nicotiana tabacum L.) using an ethyl methanesulfonate (EMS)-mutagenized population of 1,536 individuals. We optimized the procedures for endonuclease preparation, leaf tissue sampling, DNA extraction, normalization, pooling, PCR amplification, heteroduplex formation, and capillary electrophoresis. In a test screen using seven target genes with eight PCR fragments, we obtained 118 mutants. The mutation density was estimated to be approximately one mutation per 106 kb on average. Phenotypic analyses showed that mutations in two heavy metal transporter genes, HMA2S and HMA4T, led to reduced accumulation of cadmium and zinc, which was confirmed independently using CRISPR/Cas9 to generate knockout mutants. Our results demonstrate that this powerful TILLING platform (available at http://www.croptilling.org) can be used in tobacco to facilitate functional genomics applications.

Clinical efficacy of different treatments and their impacts on the quality of life of octogenarians with coronary artery disease.

BACKGROUND: Coronary artery disease (CAD) in octogenarians (age of ≥80 years) has a high risk of mortality and high medical expenses. Research shows that the prevalence of CAD is higher among octogenarians than that among younger people, but few such patients undergo percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). This study aimed to evaluate different treatments with respect to their clinical effects and impacts on quality of life of octogenarians with CAD. METHODS: Data of 519 octogenarians with CAD consecutively treated at Beijing Anzhen Hospital, Capital Medical University (Beijing, China) from January 2010 to January 2016 were collected in this study. The patients were categorized into three groups based on the treatments they received: the PCI group (n = 292), CABG group (n = 110), and medical treatment group (n = 117). The followings were recorded during follow-up: clinical data, death (all-cause and cardiovascular-related), re-hospitalization time, Seattle Angina Questionnaire (SAQ) score, and occurrence of hemorrhagic events (cerebral bleeding, gastrointestinal bleeding, and dermal ecchymosis). RESULTS: The median follow-up duration was 25.0 (25th, 75th percentile: 17.0, 55.5) months among 417 patients. The all-cause death rates (28.2% vs. 12.0% and 14.6%, respectively) and cardiovascular-related death rates (15.4% vs. 3.8% and 6.4%, respectively) were significantly higher in the medical treatment group than those in the PCI group and CABG group (all P < 0.05). The re-hospitalization rate for cardiovascular events was significantly lower in the CABG group than those in the PCI group and medical treatment group (3.8% vs. 12.8% and 14.9%, respectively) (χ = 8.238, P = 0.018). The SAQ scores of physical limitation, angina frequency, treatment satisfaction, and disease perception were significantly higher in the PCI group and CABG group than those in the medical treatment group (all P < 0.05). No significant difference in the angina stability score was observed among the three groups (F = 3.179, P = 0.204). CONCLUSION: PCI and CABG result in reduced mortality and better quality of life in octogenarians with CAD.

Co-Infection with Marek's Disease Virus and Reticuloendotheliosis Virus Increases Illness Severity and Reduces Marek's Disease Vaccine Efficacy.

Marek's disease virus (MDV) and reticuloendotheliosis virus (REV) cause Marek's disease (MD) and reticuloendotheliosis (RE), respectively. Co-infection with MDV and REV is common in chickens, causing serious losses to the poultry industry. However, experimental studies of such co-infection are lacking. In this study, Chinese field strains of MDV (ZW/15) and REV (JLR1501) were used as challenge viruses to evaluate the pathogenicity of co-infection and the influence of MD vaccination in chickens. Compared to the MDV-challenged group, the mortality and tumor rates increased significantly by 20.0% (76.7 to 96.7%) and 26.7% (53.3 to 80.0%), in the co-challenged group, respectively. The protective index of the MD vaccines CVI988 and 814 decreased by 33.3 (80.0 to 47.7) and 13.3 (90.0 to 76.7), respectively. These results indicated that MDV and REV co-infection significantly increased disease severity and reduced the vaccine efficacy. The MDV genome load showed no difference in the feather pulps and spleen, and pathogenicity-related MDV gene expression (meq, pp38, vIL-8, and ICP4) in the spleen significantly increased at some time points in the co-challenged group. Clearly, synergistic pathogenicity occurred between MDV and REV, and the protective efficacy of existing MD vaccines was attenuated by co-infection with Chinese field MDV and REV strains.

A Chinese Variant Marek's Disease Virus Strain with Divergence between Virulence and Vaccine Resistance.

Marek's disease (MD) virus (MDV) has been evolving continuously, leading to increasing vaccination failure. Here, the MDV field strain BS/15 was isolated from a severely diseased Chinese chicken flock previously vaccinated with CVI988. To explore the causes of vaccination failure, specific-pathogen free (SPF) chickens vaccinated with CVI988 or 814 and unvaccinated controls were challenged with either BS/15 or the reference strain Md5. Both strains induced MD lesions in unvaccinated chickens with similar mortality rates of 85.7% and 80.0% during the experimental period, respectively. However, unvaccinated chickens inoculated with BS/15 exhibited a higher tumor development rate (64.3% vs. 40.0%), but prolonged survival and diminished immune defects compared to Md5-challenged counterparts. These results suggest that BS/15 and Md5 show a similar virulence but manifest with different pathogenic characteristics. Moreover, the protective indices of CVI988 and 814 were 33.3 and 66.7 for BS/15, and 92.9 and 100 for Md5, respectively, indicating that neither vaccine could provide efficient protection against BS/15. Taken together, these data suggest that MD vaccination failure is probably due to the existence of variant MDV strains with known virulence and unexpected vaccine resistance. Our findings should be helpful for understanding the pathogenicity and evolution of MDV strains prevalent in China.

Characterization of a Gallid herpesvirus 2 strain with novel reticuloendotheliosis virus long terminal repeat inserts.

A bacterial artificial chromosome clone, designated LCY, was constructed from a Gallid herpesvirus 2 (GaHV-2) isolate from a GaHV-2 and reticuloendotheliosis virus co-infected clinical sample. The LCY GaHV-2 insert was sequenced and found to consist of 175,319 nucleotides. LCY GaHV-2 open reading frames (ORFs) had a high sequence identity to those of reference strains. The major difference was that two REV long terminal repeats (LTRs), in the same direction, were inserted at the internal repeat short (IRs)/unique short (Us) and Us/terminal repeat short (TRs) junctions. In addition, the a-like sequence and UL36 were different from other strains. Phylogenetic analysis revealed that LCY was closely related to pandemic strains in China. A pathogenicity study and a vaccination-challenge test were performed on LCY and the reference strain, GA. The results showed that LCY induced gross Marek's disease (MD) lesions and mortality in 71.4 and 7.1% of chickens, respectively, which are lower rates than those observed for the reference strain GA (85.7 and 35.7%). The commercially available CVI988 vaccine provided complete protection against LCY and GA (100%). These results showed that the isolate exhibited lower pathogenicity in SPF chickens. This study revealed that a novel pattern of LTR inserts was found in the strain LCY and that the strain was of low virulence. The present work expands the available genetic information for GaHV-2 and will be useful for the control of MD in China.

Integrin αvß1 Modulation Affects Subtype B Avian Metapneumovirus Fusion Protein-mediated Cell-Cell Fusion and Virus Infection.

Avian metapneumovirus (aMPV) fusion (F) protein mediates virus-cell membrane fusion to initiate viral infection, which requires F protein binding to its receptor(s) on the host cell surface. However, the receptor(s) for aMPV F protein is still not identified. All known subtype B aMPV (aMPV/B) F proteins contain a conserved Arg-Asp-Asp (RDD) motif, suggesting that the aMPV/B F protein may mediate membrane fusion via the binding of RDD to integrin. When blocked with integrin-specific peptides, aMPV/B F protein fusogenicity and viral replication were significantly reduced. Specifically we identified integrin αv and/or ß1-mediated F protein fusogenicity and viral replication using antibody blocking, small interfering RNAs (siRNAs) knockdown, and overexpression. Additionally, overexpression of integrin αv and ß1 in aMPV/B non-permissive cells conferred aMPV/B F protein binding and aMPV/B infection. When RDD was altered to RAE (Arg-Ala-Glu), aMPV/B F protein binding and fusogenic activity were profoundly impaired. These results suggest that integrin αvß1 is a functional receptor for aMPV/B F protein-mediated membrane fusion and virus infection, which will provide new insights on the fusogenic mechanism and pathogenesis of aMPV.

Molecular and pathogenicity characterization of Gallid herpesvirus 2 newly isolated in China from 2009 to 2013.

During the course of our continuous surveillance of Gallid herpesvirus 2 (GaHV-2), 44 isolates were obtained from GaHV-2-positive chickens of different flocks in China from 2009 to 2013. The meq gene, considered as a major GaHV-2 oncogene, was sequenced and was found to contain an open reading frame of 1020 nucleotides encoding a 339 amino acid (aa) polypeptide in all isolates. Compared with the GaHV-2 GA strain, the meq genes in 15.9 % (7/44) of the isolates analyzed in this study contained an aa substitution mutation at position 88 (A to T) of which is the first report. The main characteristics of Chinese GaHV-2 isolates meq genes included the substitutions K77E, D80Y, V115A, T139A, P176R, and P217A, and the aa substitution frequency at positions 139 and 176 showed an increase. To test the pathogenicity of the isolates, a pathogenicity study and a vaccination-challenge test were performed on three selected isolates (ZY/1203, WC/1203, and WC/1110) and reference strain GA. The results showed that the three isolates induced gross Marek's disease (MD) lesions in 95.0-100 % cases, which was a higher rate than that obtained for strain GA (82.4 %). Three isolates induced mortality in 10-21.1 % of specific-pathogen-free chickens, which was similar to results with strain GA (23.5 %). The commercially available CVI988 vaccine induced lower protective indices (PIs) against ZY/1203 (82.4) and WC/1110 (83.3) as compared to those against WC/1203 (100) and GA (100). These results showed an evolving trend in the meq genes of the isolates; three isolates exhibited higher morbidity as compared to the reference strain and the vaccine induced lower PIs against two isolates as compared to that against the reference strain.

Isolation and full-genome sequence of two reticuloendotheliosis virus strains from mixed infections with Marek's disease virus in China.

Reticuloendotheliosis virus (REV), classified as a gammaretrovirus, has a variety of hosts, including chickens, ducks, geese, turkeys, and wild birds. REV causes a series of pathological syndromes, especially the immunosuppression of the host, which may lead to an increased susceptibility to other pathogens, thus greatly damaging the poultry industry. Mixed infections of REV and Marek's disease virus (MDV) have been reported in many countries, including China. Previous reports revealed that MDV vaccines were not efficacious, and even less-virulent MDV strains would cause some losses due to mixed infections with REV. Additionally, contaminants in the MDV vaccine might be the main source of REV. In this study, two clinical samples were collected from two flocks of chickens that were diagnosed with MDV. Subsequently, two REV isolates were obtained from the clinical samples. The isolates, named CY1111 and SY1209, were further confirmed through an indirect immunofluorescence assay and electron microscopy. Complete genome sequences of the two REV strains were determined to test the relationship between them and other REV strains. Phylogenetic trees showed that the two REV strains were closely related to most REV strains that were isolated from a variety of hosts. Therefore, REVs might spread freely among these hosts under natural conditions. Additionally, most REV strains in China were in the same clade. The present work offers some information regarding REV in China.

Pathogenic characteristics of Marek's disease virus field strains prevalent in China and the effectiveness of existing vaccines against them.

The virulence of Marek's disease virus (MDV) is continuously evolving, and more virulent MDV pathotypes are emerging, thereby reducing the effectiveness of the existing vaccines. In this study, feather pulps were collected from diseased chickens in commercial chicken flocks in China that presented significant MD visceral tumors in 2011 and were inoculated into a monolayer of duck embryo fibroblasts (DEFs). Three field isolates of MDV were obtained by plaque cloning and identified as MDV via PCR and designated strains LCC, LLY, and LTS. Unvaccinated and CVI988 vaccine-vaccinated specific pathogen-free chickens were challenged at 7 days post vaccination (dpv) with 1000 plaque forming units of each of the respective MDV isolates. These strains induced gross MD lesions in all (100%) of the unvaccinated chickens, and the mortality rates of the unvaccinated chickens were 42.9%, 46.7%, and 23.1% by 60 days post challenge (dpc), respectively. The CVI988 vaccine induced protective indices (PIs) of 85.7, 92.3, and 66.7, respectively. These results showed that the pathogenic characteristics of the Chinese isolates were diverse and that vaccine CVI988 provided different levels of protection against them. These data indicated that the existence of variant MDV strains was a possible reason of immunity failure in China.

Identification of a linear B-Cell epitope on avian reovirus protein sigmaC.

SigmaC (σC) protein, which mediates virus attachment to target cells, is the most variable proteins of avian reovirus (ARV). It is responsible for inducing protective antibody immune responses in animals. To understand the antigenic determinants of σC protein, a set of partially overlapping and consecutive peptides spanning σC were expressed and then screened with the monoclonal antibody (mAb) 2B5 directed against σC. The mAb 2B5 recognized peptides with the σC motif (45)ELLHRSISDISTTV(58). Further identification of the displayed B-cell epitope was conducted with a set of truncated peptides expressed as GST fusion proteins. The Western blot and ELISA results indicated that (45)ELLHRSISDI(54) was the minimal determinant of the linear B-cell epitope. Using sequences analysis, we found that this epitope was not a common motif shared among the other members of the ARV and DRV groups. Furthermore, cross reactivity analysis showed that the associated coding motif of other ARV and DRV groups was not recognized by 2B5. These data suggested that (45)ELLHRSISDI(54) was a type-specific linear B-cell epitope of avian reovirus. The results in this study may have potential applications in the development of diagnostic techniques and epitope-based marker vaccines against ARV, which is prevalent in China.

[Clinical and coronary angiographic features of young women with acute myocardial infarction].

OBJECTIVE: To observe the clinical and coronary angiographic features of young women (≤ 44 years) with acute myocardial infarction (AMI). METHODS: Clinic and coronary angiographic features were compared among 57 young women with AMI and 60 non-CHD young women, 78 young men with AMI and 80 elderly women with AMI were included, all patients were admitted to hospital from June 2003 to December 2010 and underwent coronary angiography. Body mass index (BMI), smoking history, familial history of early coronary artery disease, essential hypertension, type 2 diabetes mellitus, hyperlipidemia, serum uric acid (UA), menopause, lipids, total bilirubin (TBil), direct bilirubin (DBil), hemoglobin (Hb), red cell distribution width (RDW), fasting blood glucose (FBG) were measured. RESULTS: (1) Prevalence of essential hypertension, hypertriglyceridemia and levels of fasting blood glucose, triglyceride, serum uric acid were significantly higher while high density lipoprotein cholesterol, and hemoglobin were significantly lower in young women with AMI group than in age-matched non-CHD control group (all P < 0.05). (2) Logistic regression analysis showed that essential hypertension (OR = 23.187), lower hemoglobin level (OR = 1.010) and uric acid (OR = 1.040) were independent risk factors for young women with AMI (all P < 0.05). (3) Coronary angiography revealed normal coronary finding in 6 cases, single-vessel disease in 35 cases (26 cases with left anterior descending artery disease) and two-vessel disease in 12 patients. The ratio of single vessel disease involved left anterior descending artery in young women was higher than that of young men and old women with AMI (all P < 0.05). CONCLUSION: Essential hypertension, lower hemoglobin and uric acid are risk factors of young women with AMI. Single vessel coronary disease is the most common coronary angiographic feature of young women with AMI.

Role of endothelial lipase in atherosclerosis.

Endothelial lipase, which is a newly identified member of the lipase family, plays an important role in high-density lipoprotein metabolism, which catalyzes the hydrolysis of high-density lipoprotein phospholipids and facilitates the clearance of high-density lipoprotein from the circulation. In addition, inflammatory cytokines, including tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta), upregulate endothelial lipase expression, and endothelial lipase also affects the expression of cytokines, which in turn play an important role in atherogenesis. Endothelial lipase expression has been associated with macrophages within human atherosclerotic lesions. However, an important challenge is to determine how endothelial lipase alters the progression of atherosclerosis. Although few data are available from human studies, it seems that plasma endothelial lipase levels in individuals with atherosclerosis might be higher than that measured in healthy individuals. Therefore, we believe that endothelial lipase might be a promising marker for atherosclerosis in clinical settings in the future.

[Preparation and primary analysis of monoclonal antibodies against VP5 protein of chicken infectious bursal disease virus].

Infectious bursal disease virus (IBDV), the causative agent of a highly contagious disease in chickens, carries a small nonstructural protein (NS). In this study, vvIBDV Gx-VP5 genes were cloned into plasmid pET30a( + ) and expressed in E. coli with IPTG inducing. BALB/c mice were immunized with the purified recombinant fusion protein. SP2/0 myeloma cells and spleen cells of BALB/c mice were fused by PEG(MW1500), three hybridoma cell lines were examined by indirect ELISA and clone for three times by limited dilution, and were named as 4B4, 6D12, 3E8. The subtype of the monoclonal antibodies were IgG1 with a subtype identified ELISA kit, and light chains were kappa. The ascites titers of monoclonal antibodies were 5 x 10(4), 3.5 x 10(4), 3 x 10(4) by indirect ELISA, respectively. Indirect ELISA and Western blot results showed that the monoclonal antibodies only acted with VP5 protein, IF analysis indicated that three monoclonal antibodies acted with IBDV Gt. There were specific fluorescence in detected Vero E6 cells which transient expressed VP5 protein by IFA. Therefore, monoclonal antibodies specific to IBDV VP5 proteins are specific method for detected VP5 proteins, and base on establish stabilize expressed VP5 protein Vero cell lines to research IBDV VP5 protein function.

Direct evidence of reassortment and mutant spectrum analysis of a very virulent infectious bursal disease virus.

The complete genomic sequence of very virulent infectious bursal disease virus (vvIBDV) Gx strain was determined, including the sequences of segment A, encoding the precursor polyprotein, and segment B, encoding the viral RNA polymerase (VP1) and 5'- and 3'-untranslating regions. Alignment of segment A of Gx with the sequences of 12 other vvIBDV strains showed 97.5% to 99.0% amino acid identity, whereas alignment of segment B of Gx with nine other vvIBDV strains revealed high sequence divergence, ranging from 10.3% to 11%. Phylogenetic analysis of segments A and B showed that they were in different branches, indicating that the reassortment occurred in this strain and that segment A and segment B derived from different pathotype strains. The mutant spectrum analysis of quasispecies virus demonstrated that the mean minimum mutation frequency in VP1 was 8.78-fold higher than in the polyprotein. The most frequent mutations were in the first 1986 nucleotides (nonsynonymous mutations) and the last 660 nucleotides (synonymous mutations), indicating that the 219 amino acid residues in the C-terminal of the VP1 form a functional region.