The significance of the individual Meq-clustered miRNAs of Marek's disease virus in oncogenesis.

Marek's disease virus (MDV) is an important oncogenic alphaherpesvirus that induces rapid-onset T-cell lymphomas in its natural hosts. The Meq-clustered miRNAs encoded by MDV have been suggested to play potentially critical roles in the induction of lymphomas. Using the technique of bacterial artificial chromosome mutagenesis, we have presently constructed a series of specific miRNA-deleted mutants and demonstrate that these miRNAs are not essential for replication of MDV and have no effects on the early cytolytic or latent phases of the developing disease.

Virus-encoded miR-155 ortholog is an important potential regulator but not essential for the development of lymphomas induced by very virulent Marek's disease virus.

The microRNA (miRNA) mdv1-miR-M4, a functional miR-155 ortholog encoded by oncogenic Marek's disease virus (MDV), has previously been suggested to be involved in MDV pathogenesis. Using the technique of bacterial artificial chromosome mutagenesis, we have presently evaluated the potential role of mdv1-miR-M4 in the oncogenesis of the very virulent (vv) MDV strain GX0101. Unexpectedly, deletions of the Meq-cluster or mdv1-miR-M4 alone from the viral genome strongly decreased rather than abolished its oncogenicity.

[The ALV-A/B specific antibodies correlation between ELISA and IFA detection in chicken serum].

To study the correlation between ELISA and IFA tests in detection of ALV-A/B antibody in chicken sera, ELSA S/P values and IFA titers for different serum samples were measured and statistically analyzed. The results indicated that there was a strong positive correlation between ELISA S/P values and IFA titers (r = 0.97435, P < 0.

[Identification of a new subgroup of avian leukosis virus isolated from Chinese indigenous chicken breeds].

In order to clarify Avian leukosis virus (ALV) characteristics from Chinese native chicken breeds, three ALV JS11C1, JS11C2 and JS11C3 were isolated from Chinese native breed "luhua" by inoculation of DF1 cell culture and detection of p27 antigen. Using PCR amplification of env gene, the amplified gp85 genes were analyzed and compared to all six chicken ALV subgroups reported. The gp85 genes of these three viruses were 1 005bp in length and encoded 335 amino acids, and the gp37 genes were 609bp and encoded 203 amino acids.

[Antigenic comparative analysis of Newcastle disease viruses with evolutional mutations in HN and F genes under antibody immune pressures].

In chicken fibroblast cell (CEF) cultures with antiserum against Newcastle disease virus (NDV) strain TZ060107, the virus was passed serially for 50 passages in 3 independent lineages. HN and F genes were amplified and sequenced every 10 passages. The derived virus A1-50 with most mutations among 3 lineages was further passed for another 50 passages in CEF with or without antiserum against A1-50, each in 3 independent lineages.

Aging affects epidermal Langerhans cell development and function and alters their miRNA gene expression profile.

Immunosenescence is a result of progressive decline in immune system function with advancing age. Epidermal Langerhans cells (LCs), belonging to the dendritic cell (DC) family, act as sentinels to play key roles in the skin immune responses. However, it has not been fully elucidated how aging affects development and function of LCs.

Evolution of quasispecies diversity for porcine reproductive and respiratory syndrome virus under antibody selective pressure.

To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyzed with DNAStar software. Nucleic acid sequence homology was 97.

[Influence of antibody-mediated immune pressure on neuraminidase gene mutations of avian influenza virus H9N2].

LG1 strain of avian influenza virus H9N2 was passaged continuously for 40 generations in chicken embryos with anti-LG1 maternal antibodies in 4 parallel experiments, of which 3 experiments had a stable mutation of "G" to "A" at #99 of the neuraminidase gene(NA)from the 20th passage resulting in a change of Met to Ile and 2 had a stable mutation of "A" to "G" at #473 of the NA gene from the 30th passage resulting in a change of Asn to Ser which occurred in the 50th passage of another experiment. Eighty continuous passages in chicken embryos without antibody did not have the same mutation, indicating that the mutations of the 2 positions were associated with selective pressure of antibodies. Analysis of the ratios of nonsynonium (NS) vs synonium (S) mutations of nucleic acids demonstrated that NS/S of 4 parallel experiments with antibodies was 4.

[Correlation between TCID50 and p27 antigen of avian leukosis virus subgroup J].

To study the correlation between 50% tissue-culture infective dose (TCID50) value and p27 antigen S/P value of Avian leukosis virus subgroup J and discuss their significance, chicken embryo fibroblast (CEF) cells were inoculated with Avian leukosis virus subgroup J strain NX0101 and samples were tested continuously for ten days after changing maintenance media. The correlation between TCID50 and p27 antigen S/P value of ten days were then analysized. Simultaneously, DF-1 cells were inoculated with NX0101 and passaged to 20 generations.

[Comparison of whole genome sequences and replication ability in cell cultures between two avian leukosis viruses of subgroup B].

The purpose of this study was to compare the whole genome sequences and replication dynamics in cell cultures of two Avian leukosis viruses of subgroup B (ALV) isolates, SDAU09E3 and SDAU09C2. Comparison of the amino acid sequences indicated that the gp85 identity of these two subgroup B isolates was 95.4%, the identity with other three ALV-B reference strains was 91.

Epitope variation in the Newcastle disease virus HN gene under antibody immune selective pressure in cell culture.

The influence of antibody immune selective pressure on Newcastle disease virus (NDV) HN and F gene mutations was studied in cell cultures. NDV field strain TZ060107 was inoculated into chicken embryo fibroblast cells and continuously passaged with (group A) or without (group B) anti-NDV monospecific serum. Each group contained three independent passage series.

Expression profiles of microRNAs encoded by the oncogenic Marek's disease virus reveal two distinct expression patterns in vivo during different phases of disease.

Marek's disease virus (MDV) is a long-recognized oncogenic herpesvirus, which induces lymphoma in its natural host that can be prevented by vaccination. MDV infection provides an excellent biological model for investigating the biology, genetics and immunology of viral oncogenesis. Recently discovered microRNAs (miRNAs) in the MDV genome have been suggested to have regulatory roles during MDV oncogenesis.

Molecular epidemiological investigation of Marek's disease virus from Guangxi, China.

The predominant field strains of Marek's disease virus in Guangxi were clearly different from the vaccine strain CVI988/Rispens based on sequencing of the envelope glycoprotein I (gI), glycoprotein E (gE) and oncogenic meq genes. These differences may be partly responsible for the most recent outbreaks in Guangxi.

Isolation and identification of a subgroup A avian leukosis virus from imported meat-type grand-parent chickens.

An exogenous avian leukosis virus (ALV) strain SDAU09C1 was isolated in DF-1 cells from one of 240 imported 1-day-old white meat-type grand parent breeder chicks. Inoculation of SDAU09C1 in ALV-free chickens induced antibody reactions specific to subgroup A or B. But gp85 amino acid sequence comparisons indicated that SDAU09C1 fell into subgroup A; it had homology of 88.

[Isolation and identification of a subgroup B avian leukosis virus from chickens of Chinese native breed Luhua].

By inoculation of blood samples in DF-1 (C/E) cell culture, an exogenous avian leukosis virus (ALV) strain SDAU09C2 was isolated from a breeder farm of Chinese native breed "Luhua" in Shandong province. Comparisons of the amino acid sequence of env gene gp85 from the isolate with those from other ALV reference strains of different subgroups indicated that SDAU09C2 had the highest gp85 identity to two reference strains of subgroup B of 92.5%.

Functional evaluation of the role of reticuloendotheliosis virus long terminal repeat (LTR) integrated into the genome of a field strain of Marek's disease virus.

MDV-GX0101 is a field strain of Marek's disease virus with a naturally occurring insertion of the reticuloendotheliosis virus (REV) LTR fragment. In order to study the biological properties of REV-LTR insertion in the MDV genome, we constructed a full-length infectious BAC clone of MDV-GX0101 strain and deleted the LTR sequences by BAC mutagenesis. The pathogenic properties of the LTR-deleted virus were evaluated in infected SPF birds.

Analysis of immunological enhancement of immunosuppressed chickens by Chinese herbal extracts.

Ethnopharmacological Relevance: Radix astragali, Radix codonopis, Herba epimedii and Radix glycyrrizae are 4 plants commonly used in Chinese traditional medicine or veterinary medicine to improve immune functions against chronic diseases in humans and animals.

Aim Of The Study: We compared immunological enhancement by 4 herbal extracts in clinical healthy chickens or immunosuppressed chickens singly and in combination.

Materials And Methods: Water extracts of 4 herbs individually and in different combinations were supplemented in drinking water.

[The identification and sequence analysis of ALV-J isolated from layers].

Two Avian leukosis viruses of subgroup J (ALV-J) were isolated from layers by inoculating the sample into chicken embryo fibroblast (CEF) cells and by indirect fluorescent assay (IFA) with ALV-J specific monoclonal antibody JE-9. Sequence comparison indicated the gp85 identities were only in the ranges of 83.4%-87.

Study on the structure of heteropolymer pp38/pp24 and its enhancement on the bi-directional promoter upstream of pp38 gene in Marek's disease virus.

In the latest report, Chloramphenicol acetyltransferase (CAT) gene was used as a reporter to investigate the influence of pp38 on its upstream bi-directional promoter, and it was found that the co-expression of pp38 and pp24 can significantly enhance the transactivity of the bi-directional promoter between pp38 gene and 1.8-kb mRNA transcript in genome of Marek's disease virus (MDV). In this study, enhanced green fluorescence protein (EGFP) gene was used as another reporter to further investigate the promoter activity.

[Pathogenicity and genomic sequence comparison of a chicken infectious anemia virus field isolate].

A field strain C14 of chicken infectious anemia virus (CAV) was isolated from a 14 day-old broiler flock with growth runting syndromes. Antibody reactions to inactivated vaccines to avian influenza viruses (AIV) were suppressed in SPF chickens inoculated with C14 strain CAV at 1 day-old. Also C14 strain CAV and reticuloendotheliosis Virus demonstrated a synergism in immunosuppression when chickens were infected with both virus.

Molecular characterization of three new virulent Newcastle disease virus variants isolated in China.

Three cases of Newcastle disease virus (NDV) found in nature had the lentogenic motif (112)G-R-Q-G-R-L(117) in their fusion protein cleavage sites. However, both intracerebral pathogenicity and intravenous pathogenicity indexes showed that these NDV isolates were virulent. In comparison with the LaSota live virus vaccine, these viruses had significant genetic variations in the hemagglutinin-neuraminidase gene.

[Genetic characterization and correlation among fragments of HN gene of the field Newcastle disease viruses].

Twenty-four isolates of Newcastle disease virus (NDV) prevailing during 1997 -- 2005 in China were collected. These isolates were purified by CEF plaque assay and replicated in SPF chicken embryos. The hemagglutinin-neuraminidase (HN) genes of these viruses were cloned and sequenced.

[Influence of avian reovirus infection on the Bursa and immune-reactions in chickens].

The influences of avian reovirus (ARV) infection at 1 day of age on bursa development, antibody responses after vaccinations to avian influenza virus (AIV), Newcastle disease virus (NDV) and infectious bursal disease virus (IBDV), and pathogenecity of virulent IBDV (v-IBDV) were studied in chickens of SPF-origin. The results indicated that LY strain ARV infection in 1-day-old chickens caused atrophy of the Bursa and decreased lymphocyte numbers in the bursa, but it gave no significant negative effects on growth rates and antibody titers to AIV and NDV after vaccination. LY strain ARV infection decreased antibody titers to IBDV in B87 vaccinated birds but all vaccinated birds infected with ARV were still full protected from death or clinical syndromes after v-IBDV challenge.