Chicken Embryo Fibroblast Cells Research Articles

Antiproliferative effect and characterization of a novel antifungal peptide derived from human Chromogranin A.

CGA-N46 is a novel antifungal peptide derived from the N-terminus of human Chromogranin A, corresponding to the 31st to 76th amino acids. Further research on its activities and characteristics may be helpful for the application of CGA-N46 in medical or other situations. In the present study, the antifungal spectrum and physicochemical characteristics of CGA-N46 were investigated using an antifungal assay, its antiproliferative effects on cancer and normal cells were assessed using MTT assay and its combinatorial effect with other antibiotics was analyzed using checkerboard analysis. The results showed that CGA-N46 exhibited antifungal activity against the tested Candidas (C. glabrata, C. parapsilosis, C. krusei, C. tropicalis and C. albicans) at a concentration of <0.8 mM, but had no effect on the growth of filamentous fungi or other types of fungi (Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Fusarium moniliforme, Microsporum canis, Microsporum gypseum, Trichophyton rubrum and Trichophyton mentagrophytes), even at a concentration of 3.2 mM. CGA-N46 had an inhibitory effect on the proliferation of lung cancer A549 cells and a reversible effect on the growth of normal primary chicken embryo fibroblast cells, but no hemolytic activity on human erythrocytes at the minimum inhibitory concentration of CGA-N46 against yeasts. The antifungal activity of CGA-N46 was stable at a temperature <40°C or within a broad pH range (pH 5.0-7.0). Its antifungal activity was enhanced when the peptide was used in combination with fluconazole and terbinafine. The present results indicate that CGA-N46 is a safe, physicochemically stable, antifungal peptide with anticancer cell activity that exhibits an additive effect with conventional antibiotics.

S1PR1 expression correlates with inflammatory responses to Newcastle disease virus infection

Newcastle disease virus (NDV) is the causative agent of Newcastle disease, which is characterized by inflammatory pathological changes in the organs of chickens. The inflammatory response to this disease has not been well characterized. Previous reports showed that the sphingosine-1-phosphate-1 receptor (S1PR1), a G protein-coupled receptor, is important to the activation of inflammatory responses. To understand better the viral pathogenesis and host inflammatory response, we analyzed S1PR1 expression during NDV infection. We observed a direct correlation between chicken embryo fibroblast (CEF) cellular inflammatory responses and S1PR1 expression. Virulent NDV-infected CEF cells also had elevated levels of pro-inflammatory cytokines (IL-1β, IL-6 and IL-18). When S1PR1 was inhibited by using the specific antagonist W146, pro-inflammatory cytokine production declined. Overexpression of S1PR1 resulted in increased virus-induced IL-1β production. S1PR1 expression levels did not impact significantly NDV replication. These findings highlight the important role of S1PR1 in inflammatory responses in NDV infection.

ID: 130: Immunodulation and proviral action of chicken Suppressor of Cytokine Signaling 1 (SOCS1)

We conducted microarray analysis of the increasingly popular chicken DF-1 cell line and its primary progenitor, chicken embryo fibroblast cells (CEF), in both normal and stimulated conditions using recombinant chicken IFN- α and the CEF-adapted infectious bursal disease virus vaccine strain PBG98. We found that DF-1 cells have an attenuated innate immune response compared to CEF, and also that chicken SOCS1 (ChSOCS1), a negative regulator of cytokine signaling, is expressed at levels 13-fold higher in DF-1 cells than in CEF. We found that overexpressing ChSOCS1 in CEF reduced levels of phosphorylated STAT1 protein in response to viral infection but that its “SOCS box protein” domain (which, in mammalian SOCS1, interacts with an E3 ubiquitin ligase complex) is not essential for the inhibition of cytokine-induced JAK/STAT signaling activation in DF-1 cells. Overexpression of SOCS1 in DF-1 cells led to a significant relative decrease in expression of IFN- β , MX1, IFIT5 and MDA5 in response to PBG98 infection, and increased viral yield. Conversely, knockdown of SOCS1 increased ISG induction and reduced viral yield in IFN-stimulated DF-1 cells. Our results show that, like its mammalian counterpart, ChSOCS1 reduces induction of the IFN signaling pathway.

Assessment of the pathogenicity of cell-culture-adapted Newcastle disease virus strain Komarov.

Newcastle disease vaccines hitherto in vogue are produced from embryonated chicken eggs. Egg-adapted mesogenic vaccines possess several drawbacks such as paralysis and mortality in 2-week-old chicks and reduced egg production in the egg-laying flock. Owing to these possible drawbacks, we attempted to reduce the vaccine virulence for safe vaccination by adapting the virus in a chicken embryo fibroblast cell culture (CEFCC) system. Eighteen passages were carried out by CEFCC, and the pathogenicity was assessed on the basis of the mean death time, intracerebral pathogenicity index, and intravenous pathogenicity index, at equal passage intervals. Although the reduction in virulence demonstrated with increasing passage levels in CEFCC was encouraging, 20% of the 2-week-old birds showed paralytic symptoms with the virus vaccine from the 18th(final) passage. Thus, a tissue-culture-adapted vaccine would demand a few more passages by CEFCC in order to achieve a complete reduction in virulence for use as a safe and effective vaccine, especially among younger chicks. Moreover, it can be safely administered even to unprimed 8-week-old birds.

Delayed Newcastle disease virus replication using RNA interference to target the nucleoprotein

Each year millions of chickens die from Newcastle disease virus (NDV) worldwide leading to severe economic and food losses. Current vaccination campaigns have limitations especially in developing countries, due to elevated costs, need of trained personnel for effective vaccine administration, and functional cold chain network to maintain vaccine viability. These problems have led to heightened interest in producing new antiviral strategies, such as RNA interference (RNAi). RNAi methodology is capable of substantially decreasing viral replication at a cellular level, both in vitro and in vivo. In this study, we utilize microRNA (miRNA)-expressing constructs (a type of RNA interference) in an attempt to target and knockdown five NDV structural RNAs for nucleoprotein (NP), phosphoprotein (P), matrix (M), fusion (F), and large (L) protein genes. Immortalized chicken embryo fibroblast cells (DF-1) that transiently expressed miRNA targeting NP mRNA, showed increased resistance to NDV-induced cytopathic effects, as determined by cell count, relative to the same cells expressing miRNA against alternative NDV proteins. Upon infection with NDV, DF-1 cells constitutively expressing the NP miRNA construct had improved cell survival up to 48 h post infection (h.p.i) and decreased viral yield up to 24 h.p.i. These results suggest that overexpression of the NP miRNA in cells and perhaps live animal may provide resistance to NDV.

Detection of T- and B-cell Target Antigens of Fowlpox Virus Isolated from Backyard Chickens in India.

With the aim of assessing the antigenic characteristics of a circulating pool of fowlpox virus (FPV) that exists in the backyard poultry system in India, one of the field isolates generated was characterized by in vitro immunologic techniques. FPV was isolated from clinically positive fowlpox cases (n = 10) from the Jhargram (West Midnapur district) and Kakdwip (South 24 Pargana district) areas of West Bengal State, India. Initially, FPV-specific PCR was performed for confirmation of the samples. Isolation of FPV was done using embryonated chicken eggs and the choreoallantoic membrane route. Subsequently, FPV antigen was prepared from chicken embryo fibroblast cell culture-adapted field isolate. Biologic transmission of FPV was performed in Rhode Island red chickens experimentally to assess humoral and cell-mediated immune (CMI) responses. High level of anti-FPV antibodies were observed in test birds as assessed by indirect ELISA. Seroreactive polypeptides (B-cell antigens) of FPV antigen with molecular weights of 44.5, 66.5, 75, 90.5, and 99 kDa were detected by western blot analysis. Significant increases in CMI responses were observed in inoculated chickens as assessed by lymphocyte proliferation assay, cytotoxicity assay, and T-cell immunoblotting. The predominant T-cell antigen of FPV detected had a molecular weight of 66.5 kDa. The present study revealed the antigenic characteristics of FPV that exists in backyard poultry system in West Bengal for the first time, thus exploring the rationality of designing future T- and B-cell vaccines against fowlpox.

Transcriptional Profiling of Host Gene Expression in Chicken Embryo Fibroblasts Infected with Reticuloendotheliosis Virus Strain HA1101.

Reticuloendotheliosis virus (REV), a member of the Gammaretrovirus genus in the Retroviridae family, causes an immunosuppressive, oncogenic and runting-stunting syndrome in multiple avian hosts. To better understand the host interactions at the transcriptional level, microarray data analysis was performed in chicken embryo fibroblast cells at 1, 3, 5, and 7 days after infection with REV. This study identified 1,785 differentially expressed genes that were classified into several functional groups including signal transduction, immune response, biological adhesion and endocytosis. Significant differences were mainly observed in the expression of genes involved in the immune response, especially during the later post-infection time points. These results revealed that differentially expressed genes IL6, STAT1, MyD88, TLRs, NF-κB, IRF-7, and ISGs play important roles in the pathogenicity of REV infection. Our study is the first to use microarray analysis to investigate REV, and these findings provide insights into the underlying mechanisms of the host antiviral response and the molecular basis of viral pathogenesis.

Both MicroRNA-155 and Virus-Encoded MiR-155 Ortholog Regulate TLR3 Expression.

MicroRNA-155 (miR-155) has been as an important controller of TLR3 signalling. However, the interactions between miR-155 and TLR3 are poorly understood. Here, we focused on the regulation of the relationship between miR-155 and TLR3. Sequence analyses and firefly luciferase reporter assay revealed that miR-155 target were present in the coding sequences (CDS) of TLR3. And the expression of the TLR3 protein could be inhibited by a miR-155 mimic or by a virally encoded orthologue in chick embryo fibroblast cells. Notably, endogenous miR-155 induction emerged a negative regulation on TLR3 expression in TLR2, 4 and 7 ligands stimulated HD11 cells, an avian macrophage cell line. Moreover, treatment with the miR-155 antagomir increased TLR3 levels while significantly decreased the abundance of TLR3 with miR-155 agomir. In addition, our data showed that miR-155 could inhibit IFN-β production possibly though TLR3 signal pathway. All these findings might reveal a new mechanism by which miR-155 can regulate the TLR3 immune response.

Construction of Recombinant HVT Expressing PmpD, and Immunological Evaluation against Chlamydia psittaci and Marek’s Disease Virus

Chlamydia psittaci (C. psittaci) is an obligate intracellular zoonotic pathogen that can be transmitted to humans from birds. No efficacious commercial vaccine is available for clearing chlamydial infection due to lack of potential vaccine candidates and effective delivery vehicles. Herpesvirus of turkeys (HVT) is an efficacious commercially available vaccine against Marek’s Disease virus (MDV). In this study, a recombinant HVT-delivered vaccine against C. psittaci and Marek’s disease was developed and examined. The 5'-terminus of pmpD gene (pmpD-N) encoding the N-terminal fragment of polymorphic membrane protein D of C. psittaci was inserted into a nonessential region of HVT genome using reverse genetics based on an infectious bacterial artificial chromosome (BAC) clone of HVT. The recombinant virus (rHVT-pmpD-N) was recovered from primary chicken embryo fibroblast (CEF) cells by transfection of modified HVT BAC DNA containing the pmpD-N gene. The rHVT-pmpD-N construct was confirmed to express PmpD-N by immunoblot and immunofluorescence. The rHVT-pmpD-N was stable during 20 passages in vitro. The growth kinetics of rHVT-pmpD-N was comparable to that of parental HVT in vitro and in vivo. One-day-old SPF chickens inoculated subcutaneously with rHVT-pmpD-N displayed increased PmpD-specific antibody levels and a vigorous PmpD-specific lymphocyte proliferation response using HVT vector or CEF cells as control. Furthermore, the percentage of CD4+ cells was significantly elevated in rHVT-pmpD-N-immunized birds as compared to the parental HVT. All chickens vaccinated with rHVT-pmpD-N or parental HVT were protected completely against challenge with a very virulent strain of Marek’s Disease virus (MDV) RB-1B. Post challenge with C. psittaci CB7 strain, a significant decrease in respiratory distress, lesions and Chlamydia load was found in the rHVT-pmpD-N-vaccinated group compared to the parental HVT. In conclusion, our study suggests that the rHVT-pmpD-N live vaccine may be viable as a candidate dual vaccine that provides protection against both very virulent MDV and C. psittaci.

Regeneration of a recombinant infectious bursal disease virus having four amino acid substitutions in VP2 by reverse genetics

Infectious bursal disease virus (IBDV), a virus with a double-stranded, bi-segmented RNA genome, is an economically important pathogen of chickens. Recent understanding of the molecular biology of IBDV has implicated several amino acid residues in the capsid protein VP2 in pathogenicity and tissue culture adaptation. In the present study a recombinant strain of IBDV having four mutations in VP2 (Gln253His, Asp279Asn, Ala284Thr and Ser330Arg) has been generated using reverse genetics. Desired mutations were introduced in the VP2 gene of the cloned cDNA of genome segment A of a very virulent (vv) IBDV by site-directed mutagenesis. Capped RNA transcribed in vitro from cloned cDNA of the modified segment A and wild type segment B was co-transfected into chicken embryo fibroblast (CEF) cell culture. The recombinant virus, designated as BD- 3tcC, was rescued from the transfected cell culture and characterized in vitro. BD-3tcC retained all the four desired mutations and replicated with titres only slightly lower than those of CEF cell-culture-adapted wild-type IBDV. This recombinant strain can be used in future studies for understanding the biological significance of these four amino acid residues in VP2. DOI: http://dx.doi.org/10.3329/bvet.v31i1.22838 Bangl. vet. 2014. Vol. 31, No. 1, 12-19

Pock forming ability of fowl pox virus isolated from layer chicken and its adaptation in chicken embryo fibroblast cell culture.

Aim:The objective of the present study was to examine pock forming ability of field strain and vaccine strain of fowl pox virus (FPV) in chorioallantoic membrane (CAM) of embryonated chicken eggs and its adaptation in chicken embryo fibroblast (CEF) cell culture.Materials and Methods:Dry scabs were collected from 25 affected birds in glycerin-saline and preserved at 4°C until processed. Virus was isolated in 10-day-old embryonated chicken eggs by dropped CAM method. The identity of the virus is confirmed by clinical findings of affected birds, pock morphology and histopathology of infected CAM. In addition one field isolate and vaccine strain of FPV was adapted to CEF cell culture. CEF cell culture was prepared from 9-day-old embryonated chicken eggs.Result:Clinical symptoms observed in affected birds include pox lesion on comb, wattle, eyelids and legs, no internal lesions were observed. All field isolates produced similar findings in CAM. Pocks produced by field isolates ranged from 3 mm to 5 mm at the third passage while initial passages edematous thickening and necrosis of CAM was observed. Pocks formed by lyophilized strain were ranges from 0.5 mm to 2.5 mm in diameter scattered all over the membrane at the first passage. Intra-cytoplasmic inclusion bodies are found on histopathology of CAM. At third passage level, the CEF inoculated with FPV showed characteristic cytopathic effect (CPE) included aggregation of cells, syncytia and plaque formation.Conclusion:FPV field isolates and vaccine strain produced distinct pock lesions on CAMs. Infected CAM showed intracytoplasmic inclusion bodies. The CEF inoculated with FPV field isolate as well as a vaccine strain showed characteristic CPE at third passage level.

Molecular cloning and expression analysis of TRAF3 in chicken

Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a crucial regulator that suppresses c-Jun N-terminal kinase and non-canonical nuclear factor-kB signaling, but facilitates type I interferon production. To determine TRAF3 function in innate immune responses among birds, particularly chicken, we cloned and characterized the chicken TRAF3 gene (chTRAF3) and detected its tissue expression profile in chicken. We also detected the differential expression of chTRAF3 and its downstream gene interferon-β (IFN-β) upon different stimuli in primary chicken embryo fibroblast cells. Two chTRAF3 gene products, chTRAF3-1 and chTRAF3-2, can be produced by alternative splicing. The full-length coding sequence of chTRAF3 (chTRAF3-1) was 1704 base pairs and encoded a protein of 567 amino acids with high identity to TRAF3 homologs from mammals and other birds. The deduced amino acid sequence showed typical characteristics of TRAFs, with a RING finger domain, 2 zf-TRAF motifs, and a MATH domain. Quantitative real-time polymerase chain reaction analysis revealed broad expression of chTRAF3 in all detected tissues, with abundant expression in the spleen, thymus, lung, and small intestine. Expression of chTRAF3 was significantly upregulated in a time- and concentration-dependent manner in chicken embryo fibroblast cells challenged with poly I:C or poly dA-dT. Furthermore, chTRAF3 and IFN-β mRNA expression from chicken embryo fibroblast cells challenged with Newcastle disease virus F48E9 suffered intense suppression compared with Newcastle disease virus Mukteswar infection. Our results indicate that chTRAF3 plays important roles in defending against both RNA and DNA virus infection.

Adaptation of Capripox Virus Isolate from Goats in Heterologous Cells

An outbreak of goatpox was attended in district Durg and surrounding regions of Chhattisgarh state. Dried skin scabs were collected from 250 goats of different age groups showing clinical signs suggestive of pox. The prevalence rate was studied based on severity of clinical signs followed by confirmation with agar gel immuno diffusion (AGID) test. Positive scabs were further processed for virus isolation in embryonated chicken eggs via dropped chorio allantoic membrane (CAM) route followed by inoculation of CAM material in chinese hamster ovary and chicken embryo fibroblast cell cultures and propagated up to fifth passage level. Goatpox was reported with a prevalence rate of 74% using AGID. Distribution of disease in young animals, particularly in the kids (below 6 month) was more (45.4%) as compared to those between 6 to 24 months (31.35%) and 24 months and above (23.24%). Capripox virus showed cytopathic effect in chinese hamster ovary cells only after third passage and no cytopathic effect in chicken embryo fibroblast cells even up to fifth passage. Cytopathic effects appeared after 72 hrs in chinese hamster ovary cell and were characterized initially by rounding and clumping of cells, cytoplasmic vacuolation followed by cell detachment. Identity of capripox virus was confirmed positive in both the cultures from third to fifth passage by both AGID and countercurrent immuno electrophoresis (CIE) test. In conclusion, field isolate of capripox virus was successfully adapted and propagated on chinese hamster ovary cell following third passage.

Simultaneous alteration of residues 279 and 284 of the VP2 major capsid protein of a very virulent Infectious Bursal Disease Virus (vvIBDV) strain did not lead to attenuation in chickens.

BackgroundCell culture adaptation of very virulent infectious bursal disease virus (vvIBDV) was shown to be mainly associated with the VP2 capsid protein residues 253, 279, and 284. The single mutation A284T proved critical for cell culture tropism, but did not confer efficient virus replication, which at least required one additional mutation, Q253H or D279N. While the double mutation Q253H/A284T was unambiguously shown to confer both efficient replication in cell culture and attenuation in chickens, conflicting results have been reported regarding the replication efficiency of vvIBDV mutants bearing the D279N/A284T double mutation, and no data are hitherto available on their virulence in chickens.FindingsHere we used an in vivo reverse genetics system to assess the impact of the D279N/A284T double mutation on the replication and attenuation of a chimeric IBDV virus, whose polyprotein derived from a non-culturable vvIBDV clinical isolate. We found that the D279N/A284T double mutation did indeed confer efficient replication in chicken embryo fibroblast (CEF) cell culture, but the mutant virus remained highly pathogenic to chickens.ConclusionsThe double mutation D279N/A284T of the VP2 major capsid protein of vvIBDV is sufficient to confer cell culture tropism and replication efficiency, but does not necessarily lead to virus attenuation.

Adaptation and growth kinetics study of an Indian isolate of virulent duck enteritis virus in Vero cells

Duck virus enteritis, also known as duck plague, is a viral infection of ducks caused by duck enteritis virus (DEV). The control of the disease is mainly done by vaccination with chicken embryo adapted live virus that is known to be poorly immunogenic and elicits only partial protection. Further, the embryo propagated vaccine virus pose a threat of harboring other infectious agents. Seeing these limitations, the present study reports for the first time regarding propagation and adaptation of a virulent Indian isolate of duck enteritis virus in Vero cell line. In this study isolation of an outbreak virus from Kerala state was done in chicken embryo fibroblast cell culture (CEF). Then adapted the DEV isolate in the Vero cell line. The characteristic cytopathic effects (CPE) of clumping and fusion of Vero cells were observed starting from the 7th passage onwards. The presence of the virus and its multiplication in Vero cells was confirmed by detection of viral specific DNA and antigen by using polymerase chain reaction (PCR) and indirect immuno fluorescent assay (IIFA), respectively. PCR detection of DEV using self designed primers for US4 (gD) and UL30 (DNA Polymerase) gene has been reported for the in the present study. The kinetics of DEV in Vero cells revealed a maximum infectivity titer of 105.6 TCID 50/ml after 48hr of viral infection. Compared to chicken embryo adapted DVE vaccine virus, the Vero cell culture system is free from other infectious agents. So it will be a good candidate for cultivation and propagation of duck enteritis virus vaccine strain. Further research studies are suggested to explore the feasibility of utilizing this Vero cell culture adapted DEV isolate for developing an attenuated vaccine virus against duck virus enteritis.

Virological and immunological characterization of novel NYVAC-based HIV/AIDS vaccine candidates expressing clade C trimeric soluble gp140(ZM96) and Gag(ZM96)-Pol-Nef(CN54) as virus-like particles.

The generation of vaccines against HIV/AIDS able to induce long-lasting protective immunity remains a major goal in the HIV field. The modest efficacy (31.2%) against HIV infection observed in the RV144 phase III clinical trial highlighted the need for further improvement of HIV vaccine candidates, formulation, and vaccine regimen. In this study, we have generated two novel NYVAC vectors, expressing HIV-1 clade C gp140(ZM96) (NYVAC-gp140) or Gag(ZM96)-Pol-Nef(CN54) (NYVAC-Gag-Pol-Nef), and defined their virological and immunological characteristics in cultured cells and in mice. The insertion of HIV genes does not affect the replication capacity of NYVAC recombinants in primary chicken embryo fibroblast cells, HIV sequences remain stable after multiple passages, and HIV antigens are correctly expressed and released from cells, with Env as a trimer (NYVAC-gp140), while in NYVAC-Gag-Pol-Nef-infected cells Gag-induced virus-like particles (VLPs) are abundant. Electron microscopy revealed that VLPs accumulated with time at the cell surface, with no interference with NYVAC morphogenesis. Both vectors trigger specific innate responses in human cells and show an attenuation profile in immunocompromised adult BALB/c and newborn CD1 mice after intracranial inoculation. Analysis of the immune responses elicited in mice after homologous NYVAC prime/NYVAC boost immunization shows that recombinant viruses induced polyfunctional Env-specific CD4 or Gag-specific CD8 T cell responses. Antibody responses against gp140 and p17/p24 were elicited. Our findings showed important insights into virus-host cell interactions of NYVAC vectors expressing HIV antigens, with the activation of specific immune parameters which will help to unravel potential correlates of protection against HIV in human clinical trials with these vectors. We have generated two novel NYVAC-based HIV vaccine candidates expressing HIV-1 clade C trimeric soluble gp140 (ZM96) and Gag(ZM96)-Pol-Nef(CN54) as VLPs. These vectors are stable and express high levels of both HIV-1 antigens. Gag-induced VLPs do not interfere with NYVAC morphogenesis, are highly attenuated in immunocompromised and newborn mice after intracranial inoculation, trigger specific innate immune responses in human cells, and activate T (Env-specific CD4 and Gag-specific CD8) and B cell immune responses to the HIV antigens, leading to high antibody titers against gp140. For these reasons, these vectors can be considered vaccine candidates against HIV/AIDS and currently are being tested in macaques and humans.

Fat mass and obesity associated (FTO) gene regulates gluconeogenesis in chicken embryo fibroblast cells

Fat mass and obesity-associated (FTO) gene was found to be associated with energy homeostasis in mammals, yet the function of chicken FTO is less clear. In this study, chicken embryo fibroblast cells (DF-1) were transiently transfected to over-express (FTO+) or to knockdown (FTO−) the chicken FTO gene and were used for the functional analysis. FTO expression was significantly augmented in FTO+ cells while depressed in FTO− cells (P<0.05). FTO+ cells had significantly lower glucose yet higher lactic acid (LD) concentrations (P<0.05) in the culture media, which was associated with significantly up-regulated (P<0.05) mRNA expression of the rate-limiting gluconeogenic enzymes, glucose-6-phosphatase (G6PC) and the phosphoenolpyruvate carboxykinase-mitochondrial (PEPCK-m). The protein content and enzyme activity of G6PC were also significantly higher (P<0.05) in FTO+ cells. Moreover, CCAAT/enhancer-binding protein-beta (C/EBP-beta) and cAMP responsive element binding protein 1 (CREB1), which were found to transcriptionally regulate the expression of G6PC, were increased at the level of both mRNA (P<0.05) and protein (P<0.05) in FTO+ cells. ChIP analysis revealed significantly higher (P<0.05) binding of C/EBP-beta and phospho-CREB1 to G6PC gene promoter in FTO+ cells. In addition, the interaction of FTO and C/EBP-beta was significantly enhanced (P<0.05) in FTO+ cells. Opposite changes in G6PC expression and regulation were observed in FTO− cells. Our results indicate that chicken FTO regulates gluconeogenesis in DF-1 cells through enhanced transcriptional regulation of G6PC gene by C/EBP-beta and phospho-CREB1.

Efficient Marek's disease virus (MDV) and herpesvirus of turkey infection of the QM7 cell line that does not contain latent MDV genome

Marek's disease virus (MDV; also known as Gallid herpesvirus 2, MDV-1) causes oncogenic disease in chickens producing clinical signs that include lymphomas, visceral tumours, nerve lesions, and immunosuppression. MDV vaccines are widely used and mostly produced using primary cells: chicken embryo fibroblast cells, duck embryo fibroblast cells, chicken embryo kidney cells or chicken kidney cells. An immortalized cell line that can be used to manufacture the virus has long been desired. In this report, we demonstrate that QM7 cells were susceptible to infection with either MDV or herpesvirus of turkey (HVT; also known as Meleagrid herpesvirus 1, MDV-3). Polymerase chain reaction analysis with primers amplifying selected MDV genes revealed that QM7 cells did not contain these sequences. However, MDV genes were detected in QT35 cells, which have been reported to harbour latent MDV virus. Transfection of naked MDV DNA initiated efficient infection of QM7 cells. In addition, QM7 cell lysate, clarified supernatant, and QM7 cell pellet infected with MDV were negative for reverse transcriptase activity, indicating absence of endogenous retrovirus. QM7 cells were also found to be free of other avian pathogens in a chick embryo inoculation test. In vivo studies of MDV growing in QM7 cells showed the virus retained its pathogenicity and virulence. In ovo experiments demonstrated that both HVT and MDV propagated in QM7 cells did not interfere with hatchability of injected eggs, and viruses could be re-isolated from hatched chicks. The results suggest that QM7 could be a good host cell line for growing both MDV and HVT.

Inhibition of Infectious Bursal Disease Virus by Vector Delivered SiRNA in Cell Culture

Infectious Bursal Disease (IBD) is major threat to poultry industry. It causes severe immunosuppression and mortality in chicken generally at 3 to 6 weeks of age. RNA intereference (RNAi) emerges as a potent gene regulatory tool in last few years. The present study was conducted to evaluate the efficiency of RNAi to inhibit the IBD virus (IDBV) replication in-vitro. VP2 gene of virus encodes protein involved in capsid formation, cell entry and induction of protective immune responses against it. Thus, VP2 gene of IBDV is the candidate target for the molecular techniques applied for IBDV detection and inhibition assay. In this study, IBDV was isolated from field cases and confirmed by RT-PCR. The virus was then adapted on chicken embryo fibroblast cells (CEF) in which it showed severe cytopathic effects (CPE). The short hairpin RNA (shRNAs) constructs homologous to the VP2 gene were designed and one, having maximum score and fulfilling maximum Reynolds criteria, was selected for evaluation of effective inhibition. Selected shRNA construct (i.e., VP2-shRNA) was observed to be the most effective for inhibiting VP2 gene expression. Real time PCR analysis was performed to measure the relative expression of VP2 gene in different experimental groups. The VP2 gene was less expressed in virus infected cells co-transfected with VP2-shRNA as compared to mock transfected cells and IBDV+ cells (control) at dose 1.6 µg. The result showed ∼95% efficient down regulation of VP2 gene mRNA in VP2-shRNA treated cells. These findings suggested that designed shRNA construct achieved high level of inhibition of VP2 gene expression in-vitro.

Erratum to: HN protein of Newcastle disease virus causes apoptosis in chicken embryo fibroblast cells

Erratum to: HN protein of Newcastle disease virus causes apoptosis in chicken embryo fibroblast cells