Virus-induced atherosclerosis

Of four groups of chickens, two (groups I and II) were infected with MDV and two were not (groups III and IV). Groups I and III were fed diets low in lipid, and groups II and IV were fed cholesterol-supplemented diets. Striking grossly visible atherosclerotic lesions were seen in large coronary arteries, aortas, and major aortic branches of infected normocholesterolemic and hypercholesterolemic chickens (groups I and II). In contrast, grossly visible atherosclerotic lesions were not seen in uninfected normocholesterolemic chickens (group III), nor in uninfected hypercholesterolemic chickens (group IV). Microscopically, arterial changes in the infected animals were characterized by occlusive fibromuscular intimal thickening which formed fibrous caps overlying areas of atheromatous change. This change closely resembled chronic atherosclerosis in man. These results may have important bearing on our understanding of the etiology and pathogenesis of human arteriosclerosis since there is widespread and persistent infection of human populations with up to five different herpes-viruses.

Genetic mapping of quantitative trait loci affecting susceptibility to Marek's disease virus induced tumors in F2 intercross chickens

Marek's disease (MD) is a lymphoproliferative disease caused by the MD virus (MDV), which costs the poultry industry nearly $1 billion annually. To identify quantitative trait loci (QTL) affecting MD susceptibility, the inbred lines 6(3) (MD resistant) and 7(2) (MD susceptible) were mated to create more than 300 F2 chickens. The F2 chickens were challenged with MDV JM strain, moderately virulent) at 1 wk of age and assessed for MD susceptibility. The QTL analysis was divided into three stages. In stage 1, 65 DNA markers selected from the chicken genetic maps were typed on the 40 most MD-susceptible and the 40 most MD-resistant F2 chickens, and 21 markers residing near suggestive QTL were revealed by analysis of variance (ANOVA). In stage 2, the suggestive markers plus available flanking markers were typed on 272 F2 chickens, and three suggestive QTL were identified by ANOVA. In stage 3, using the interval mapping program Map Manager and permutation tests, two significant and two suggestive MD QTL were identified on four chromosomal subregions. Three to five loci collected explained between 11 and 23% of the phenotypic MD variation, or 32-68% of the genetic variance. This study constitutes the first report in the domestic chicken on the mapping of non-major histocompatibility complex QTL affecting MD susceptibility.

Establishment and characterization of a chicken mononuclear cell line

A new chicken mononuclear cell line (MQ-NCSU) has been established. The starting material used to initiate this cell line was a transformed spleen from a female Dekalb XL chicken which had been experimentally challenged with the JM/102W strain of the Marek's disease virus. After homogenization, a single cell suspension of splenic cells was cultured using L.M. Hahn medium supplemented with 10 microM 2-mercaptoethanol. Under these culture conditions, a rapidly proliferating cell was observed and then expanded after performing limiting dilution cultures. These cells were moderately adherent and phagocytic for sheep red blood cells and Salmonella typhimurium. When tested against a panel of monoclonal antibodies (mAb) using the flow cytometry, MQ-NCSU cells stained readily with anti-chicken monocyte specific (K-1) mAb but did not stain with mAb detecting T-helper, T-cytotoxic/suppressor, and NK cells. MQ-NCSU cells expressed very high levels of Ia antigens and transferrin receptors. In addition, cell-free supernatant obtained from MQ-NCSU culture contained a factor which exhibited cytolytic activity against tumor cell targets. Based on their cultural, morphological, and functional characteristics and mAb reactivity profile, we conclude that MQ-NCSU cell line represents a malignantly-transformed cell which shares features characteristic of cells of the mononuclear phagocyte lineage.

Demyelination in allergic and Marek's disease virus induced neuritis. Comparative electron microscopic studies

Patterns of demyelination were studied in sciatic nerves, spinal roots and ganglia of chickens afflicted with either Marek's disease (MD) or experimental allergic neuritis (EAN). MD was induced in susceptible chicks after hatching by inoculation of the JM strain of MD Herpes virus. Tissues from these chickens were examined 7-83 days after infection. EAN was studied 10-21 days after sensitization of 4 week old chickens to emulsions containing human peripheral nerve with complete Freund's adjuvant. In both conditions lesions were encountered which consisted of perivenular infiltrates of mononuclear cells that penetrated the basal lamina of the neurolemmal sheath, displaced Schwann cells, lysed and stripped myelin lamellae without damage to axons. Other lesions in MD were characterized by lymphomatous infiltrates that contained necrotic cells and disintegrating axons. The similarity of the demyelinating process in MD to that seen in EAN suggests that MD virus infection activates lymphocytes sensitized to peripheral nerve myelin. The findings are discussed with reference to acute idiopathic polyneuritis (Guillain-Barré syndrome) in patients with preceding or concurrent Herpes virus infections including those known to cause lymphoproliferative disorders.

Historical background

The persisting ancient view of cancer as a contagious disease ended with 19th century scientific investigations which seemed to show it was not. The resulting dogma against an infectious cause for cancer produced great prejudice in the scientific community against the first report of an oncogenic virus by Rous early in the 20th century and, even in the 1950s, against Gross's finding of a murine leukaemia virus and a murine virus causing solid tumours. The Lucké frog renal carcinoma virus was the first cancer-associated herpesvirus. Intriguingly, an environmental factor, ambient temperature, determines virus genome expression in the poikilothermic frog cells. Although an alpha-herpesvirus, Marek's disease virus of chickens shares some aspects of biological behaviour with Epstein-Barr virus (EBV) of man. Very significantly, its lymphomas are the first naturally occurring malignancy to be controlled by an antiviral vaccine, with implications for human virus-associated cancers. The circumstances and climate of opinion in which successive gamma-herpesviruses were discovered are described. The identification of EBV involved two unconventionalities: its finding in cultured Burkitt's lymphoma cells when no human lymphoid cell had ever been maintained in vitro, and its recognition in the absence of biological activity by the then new technique of electron microscopy. These factors engendered hostility to its acceptance as a new human tumour-associated virus. The EBV-like agents of Old World apes and monkeys and the T-lymphotropic gamma-herpesviruses of New World monkeys were found at about the same time, not long after the discovery of EBV. For many years these were thought to be the only gamma-herpesviruses of non-human primates; however, very recently B-lymphotropic EBV-like agents have been identified in New World species as well. Mouse herpesvirus 68 came to light by chance during a search for arboviruses and has become important as a laboratory model because of its close genetic relatedness to EBV and its comparable biological behaviour. The discovery of Kaposi's sarcoma-associated herpesvirus six years ago was made using unconventional new methods, but, unlike with EBV 30 years before, this did not hinder its acceptance. This contrast is discussed in the context of the great progress in human tumour virology which has been made in recent years.

Dual-viral vector approach induced strong and long-lasting protective immunity against very virulent infectious bursal disease virus

To induce strong protective immunity against very virulent infectious bursal disease virus (vvIBDV) in chickens, two viral vector systems, Marek's disease and Fowlpox viruses expressing the vvIBDV host-protective antigen VP2 (rMDV, rFPV), were used. Most of chickens vaccinated with the rFPV or rMDV alone, or vaccinated simultaneously with both at their hatch (rMDV-rFPV(1d)), were protected against developing clinical signs and mortality; however, only zero to 14% of the chickens were protected against gross lesions. In contrast, gross lesions were protected in 67% of chickens vaccinated primarily with the rMDV followed by boosting with the rFPV 2 weeks later (rMDV-rFPV(14d)). Protection against the severe histopathological lesions of rFPV, rMDV, rMDV-rFPV(1d), and rMDV-rFPV(14d) vaccine groups were 33, 42, 53, and 73%, respectively. Geometric mean antibody titers to VP2 of chickens vaccinated with the rFPV, rMDV, rMDV-rFPV(1d), and rMDV-rFPV(14d) before the challenge were 110, 202, 254, and 611, respectively. Persistent infection of the rMDV in chickens after the booster vaccination with rFPV was suggested by detection of the rMDV genes from peripheral blood lymphocyte DNA at 28 weeks of age. These results indicate that the dual-viral vector approach is useful for quickly and safely inducing strong and long-lasting protective immunity against vvIBDV in chickens.

Laser-induced fluorescence: III. Quantitative analysis of atherosclerotic plaque content

BACKGROUND AND OBJECTIVE

Laser-induced fluorescence (LF) spectroscopic analysis of the chemical composition of atherosclerotic plaque was examined.

STUDY DESIGN/MATERIALS AND METHODS

The intima of 18 dog aortas was injected with chemical compounds found in atherosclerotic plaque. Spectra were recorded in air prior to and after injection of collagens I, III and IV, elastin, cholesterol, triglyceride, and beta-nicotinamide adenine dinucleotide (NADH).

RESULTS

Significant changes in LF intensity were detected after injection of collagens I and III, cholesterol and elastin in thoracic aorta (P < 0.001), but not with triglyceride or NADH. Minor changes were detected in abdominal aorta. Multiple regression analysis of LF intensity ratios demonstrated a clear correlation with the quantity of injected collagens I (R2 = 0.90-0.99) and III (R2 = 0.84-1.0), cholesterol (R2 = 0.72-0.76), and triglyceride (R2 = 0.68-0.80) in both thoracic and abdominal aorta. The correlation between LF and atherosclerotic plaque composition was confirmed in a rooster model of atherosclerosis where multiple regression analysis predicted the measured aortic cholesterol (R2 = 0.78) and triglyceride content (R2 = 0.96).

CONCLUSIONS

(1) Fluorescence spectra recorded from dog aorta were significantly altered by injection of collagens I and III, cholesterol, and elastin. (2) LF may allow quantitative assessment of plaque chemical content.

The mechanism of genetic resistance to Marek's disease in chickens

Genetic resistance to Marek's disease in RPL line-6 chickens is expressed not only at the level of host immunological responses against virus an tumour antigens, but also at the level of target lymphoid cells for virus infection and transformation. The nature of the target cell involved was investigated. Spleen cells from susceptible line-7 chickens adsorbed more Marek's disease virus and turkey herpesvirus in vitro than line-6 spleen cells. In the case of Marek's disease virus this was reflected in the replicative ability of the virus in vivo. Transplantation of thymus fragments from 1-day-old line-7 chickens into thymectomized line-6 chickens conferred a high degree of susceptibility on the latter, but the transplantation of spleen or fragments had no significant effect. The reverse procedure, i.e. grafting of line-6 thymi into line-7 chickens, did not diminish the susceptibility of the recipients. In each treatment group the observed titres of leukocyte-associated viraemia correlated with the susceptibility of the group to Marek's disease. Histologically the grafted thymus fragments became depleted of lymphocytes immediately after transplantation. By 6 days there was substantial recovery, apparently as a result of re-population of the thymic epithelium by host stem cells. This was confirmed by transplanting thymus fragments between individuals of opposite sexes. Karyotype analysis showed that the thymus contained lymphocytes of the sex of the recipient. However, karyotype analysis of lymphoma cells taken from recipient line-6 chickens that had received thymus grafts from line-7 birds of the opposite sex showed that, in the majority of cases, the lymphomas consisted of cells of donor origin. It is concluded that the susceptibility of line-7 chickens is largely attributable to the greater susceptibility of their T-lymphocytes to infection and transformation by Marek's disease virus, and that this susceptibility can be transferred to genetically resistant line-6 birds by adoptive transfer of the cells in the form of thymus fragments.

Chronological study of ultrastructural changes in the peripheral nerves in Marek's disease

A chronological study was made of the ultrastructural changes in peripheral nerves following inoculation of 1-day-old chicks with a neurogenic strain of Marek Disease virus. No virus particles were found in nerves. Cellular infiltration of nerves was detected as early as 5 days after inoculation and by 3 weeks some nerves contained proliferative lesions which possessed many of the ultrastructural features characteristic of normal, reactive lymphoid tissue. About 4 weeks after inoculation, coinciding with the onset of neurological signs, areas of widespread demyelination appeared within these lesions; lymphocytes and macrophages penetrated and destroyed the myelin sheath, but spared Schwann cells and most axons. Later oedematous, sparsely infiltrated B type lesions were observed, some of which contained demyelinated nerve fibres undergoing repair; these were therefore a stage in the regression of the proliferative lesions. Our observations do not favour the hypothesis that cellular infiltration of nerves in Marek's disease is the direct result of auto-sensitization to normal myelin. They are consistent with the hypothesis that demyelination is a secondary feature and that the primary lesions are preferential sites for immune demyelination.

Avirulent Marek's disease virus type 1 strain 814 vectored vaccine expressing avian influenza (AI) virus H5 haemagglutinin induced better protection than turkey herpesvirus vectored AI vaccine

Background

Herpesvirus of turkey (HVT) as a vector to express the haemagglutinin (HA) of avian influenza virus (AIV) H5 was developed and its protection against lethal Marek’s disease virus (MDV) and highly pathogenic AIV (HPAIV) challenges was evaluated previously. It is well-known that avirulemt MDV type 1 vaccines are more effective than HVT in prevention of lethal MDV infection. To further increase protective efficacy against HPAIV and lethal MDV, a recombinant MDV type 1 strain 814 was developed to express HA gene of HPAIV H5N1.

Methodology/Principal Findings

A recombinant MDV-1 strain 814 expressing HA gene of HPAIV H5N1 virus A/goose/Guangdong/3/96 at the US2 site (rMDV-HA) was developed under the control of a human CMV immediate-early promoter. The HA expression in the rMDV-HA was tested by immunofluorescence and Western blot analyses, and in vitro and in vivo growth properties of rMDV-HA were also analyzed. Furthermore, we evaluated and compared the protective immunity of rMDV-HA and previously constructed rHVT-HA against HPAIV and lethal MDV. Vaccination of chickens with rMDV-HA induced 80% protection against HPAIV, which was better than the protection rate by rHVT-HA (66.7%). In the animal study with MDV challenge, chickens immunized with rMDV-HA were completely protected against virulent MDV strain J-1 whereas rHVT-HA only induced 80% protection with the same challenge dose.

Conclusions/Significance

The rMDV-HA vaccine was more effective than rHVT-HA vaccine for protection against lethal MDV and HPAIV challenges. Therefore, avirulent MDV type 1 vaccine is a better vector than HVT for development of a recombinant live virus vaccine against virulent MDV and HPAIV in poultry.

No homology detectable between Marek's disease virus (MDV) DNA and herpesvirus of the turkey (HVT) DNA

The relation of four different strains of MDV and two strains of HVT was analyzed by gel electrophoresis of viral DNA digested by various restriction endonucleases and by filter hybridization of viral DNA with complementary RNA. The four MDV strains showed fragment patterns completely different from those of HVT upon digestion of the viral DNA with Bam H I, Eco R I, Hind III, Hpa, I, and Xho and separation of fragments on agarose gels. The cleavage patterns of the four MDV strains showed great similarities among each other as well as some differences between the individual strains. In the cleavage patterns of HVT a similar close relationship was observed between the two HVT strains with slight divergence between both. Filter hybridizations of viral DNA with labelled complementary RNA prepared from the DNA of the GA strain of MDV or from the DNA of the PH-THV1 strain of HVT revealed no cross-hybridization between the MDV and the HVT strains. cRNA prepared from the DNA of an MDV strain hybridized only to restriction enzyme fragments of the MDV strains transferred to nitrocellulose filters, but not to fragments of HVT DNA, and vice versa.

Occurrence of acute paralysis virus of the honey bee (Apis mellifera) in a Hungarian apiary infested with the parasitic mite Varroa jacobsoni

Viruses of the honey bee have been known for a long time; however, recently the attention of scientists and apiculturalists has turned towards the relationship between these viruses and the parasitic mite Varroa jacobsoni. Although clinical symptoms indicated the presence of some of the viruses of bees in Hungary, none have previously been isolated or identified. During July unusual adult bee and brood mortality was observed in some colonies of an apiary in Budapest known to be infested with Varroa jacobsoni. Large amounts of acute paralysis virus (APV) were detected serologically in healthy honey bee pupae killed by the injection of a bacteria-free extract of diseased adult bees. Crystalline arrays of 30 nm particles were seen in ultrathin sections of the tissues of injected pupae and naturally infected adult bees. In spite of the application of acaricide treatments the bee population in several colonies had collapsed by the end of summer and the apiary suffered severe wintering losses.

Reduced incidence of Marek's disease gross lymphomas in T-cell-depleted chickens

Chickens of line 7, highly susceptible to Marek's disease (MD), were depleted of T-cells by neonatal thymectomy, total-body gamma-irradiation, and multiple injections with antithymocyte serum. In two replicate experiments, significantly fewer gross lymphomas were present in T-cell-depleted chickens than in intact or in T-cell-depleted, reconstituted hatchmates; these findings provided evidence that T-cells may be the principal target for MD virus (MDV) transformation, T-cell depletion was not complete, and the presence of microscopic lesions in T-cell-depleted chickens was attributed to residual T-cells. Ten lymphomas from intact chickens and 2 lymphomas from a T-cell-depleted chicken were examined for cellular composition. All lymphomas consisted predominantly of T-cells. The results of this and other published studies indicated that T-cells may have a dual role in MD; They may serve as a target for lymphoma formation by MDV and also may participate in immune surveillance against the disease in resistant chickens.

Ovotransferrin expression and release by chicken cell lines infected with Marek's disease virus

Mammals posses both serum transferrin and lactoferrin, whose functions are taken over in birds by ovotransferrin, displaying both iron transport and antibacterial activities. Ovotransferrin also exerts antiviral activity towards Marek's disease virus, an avian member of the herpes family of viruses. This virus infects lymphoid organs and induces the transcription of ovotransferrin in infected chicken embryo fibroblasts. However, it has not yet been established whether ovotransferrin gene transcription is linked to the release of the protein outside the cells or whether ovotransferrin expression and release also occurs in chicken lymphoblastoid cells in which the Marek's disease viral genome is integrated. Our results indicate that both serum and egg-white isoforms of ovotransferrin are expressed and released in the supernatants of chicken embryo fibroblast and lymphoblastoid cells in the absence of infection. Viral infection of chicken embryo fibroblasts caused a slight increase of ovotransferrin release, whereas viral reinfection of lymphoblastoid cells caused a remarkable ovotransferrin release in a virus concentration-dependent manner. These findings suggest that ovotransferrin release in vivo may play a crucial role in protecting the whole organism from viral infection spreading, and support the hypothesis that the antiviral activity of ovotransferrin is an important part of the innate immune response in birds, resembling the antiviral activity of lactoferrin in mammals.

Syngeneic and allogeneic cell-mediated cytotoxicity against Marek's disease lymphoblastoid tumor cell lines

Cell-mediated cytotoxicity (CMC) of lymphocytes obtained from chickens infected with Marek's disease (MD) virus against allogeneic MD lymphoblastoid cell lines has been reported by several research groups. Recently, we established a number of cell lines from MD tumors obtained from highly inbred chickens and characterized for major and minor histocompatibility antigens. Allogeneic versus syngeneic CMC was studied using those cell lines and lymphocytes obtained from chickens 6-8 days post infection with SB-1, a non-oncogenic MD virus. Allogeneic cytotoxicity could be easily demonstrated, while syngeneic cytotoxicity was a rare event. However, increase of the CMC assay period from 4 to 8 h did enhance syngeneic cytotoxicity. Cold inhibition assays demonstrated that the allogeneic cytotoxicity was directed against alloantigens present on spleen lymphocytes sharing the same major histocompatibility antigens as the target cells. Cytotoxicity was not influenced by the sex of either target or effector cells or by the level of virus infectivity of the effector cells.

The role of the reticuloendothelial system in the immunopathology of Marek's disease

The role of macrophages in immunity against Marek's disease (MD) was studied. Chickens of one group were subjected to depletion of macrophages using repeated doses of Francil amorphous silica and those of another group were subjected to activation of macrophages using repeated doses of brewer's thioglycollate broth. Chickens of a third group were vaccinated with herpesvirus of turkeys FC 126 vaccine followed by depletion of macrophages. Chickens of these three groups, as well as groups of healthy unvaccinated and healthy vaccinated chickens, were challenged with virulent MD virus. A sixth group of healthy uninfected chickens was kept as a control. The results, based on clinical signs, gross and histopathological studies and agar gel precipitation test (AGPT) for antibodies, indicated that activation of macrophages enhanced immunity against MD and depletion of macrophages had the opposite effect. The protective effect of vaccination against MD was also lowered by depletion of macrophages. The results of AGPT indicated retardation of MD virus replication by macrophage activation and the reverse on depletion.

Marek's disease virus-induced transient paralysis: a comparison of lesions in susceptible and resistant lines of chickens

A study was conducted to determine the causative lesion of Marek's disease virus-induced transient paralysis. Brain histologic lesions were quantitated and compared in genetically resistant and susceptible inbred chickens. Comparisons were made 11 days post inoculation (PI) of virus when clinical signs were evident in susceptible birds and on day 17 PI when these signs had remitted. Clinically-affected birds from the susceptible line on day 11 PI had consistent evidence of neuropil vacuolation compatible with brain edema; two of these birds also had vasculitis. These lesions were absent in both clinically-recovered birds from this line evaluated on day 17 PI and genetically resistant birds studied on day 11 PI. Our findings suggest that the causative lesion of transient paralysis is vasogenic brain edema.

Activated Chicken Gamma Delta T Cells Are Involved in Protective Immunity against Marek's Disease

Gamma delta (γδ) T cells play a significant role in the prevention of viral infection and tumor surveillance in mammals. Although the involvement of γδ T cells in Marek's disease virus (MDV) infection has been suggested, their detailed contribution to immunity against MDV or the progression of Marek's disease (MD) remains unknown. In the current study, T cell receptor (TCR)γδ-activated peripheral blood mononuclear cells (PBMCs) were infused into recipient chickens and their effects were examined in the context of tumor formation by MDV and immunity against MDV. We demonstrated that the adoptive transfer of TCRγδ-activated PBMCs reduced virus replication in the lungs and tumor incidence in MDV-challenged chickens. Infusion of TCRγδ-activated PBMCs induced IFN-γ-producing γδ T cells at 10 days post-infection (dpi), and degranulation activity in circulating γδ T cell and CD8α⁺ γδ T cells at 10 and 21 dpi in MDV-challenged chickens. Additionally, the upregulation of IFN-γ and granzyme A gene expression at 10 dpi was significant in the spleen of the TCRγδ-activated PBMCs-infused and MDV-challenged group compared to the control group. Taken together, our results revealed that TCRγδ stimulation promotes the effector function of chicken γδ T cells, and these effector γδ T cells may be involved in protection against MD.

Atherosclerosis in Marek's disease virus infected hypercholesterolemic roosters is reduced by HMGCoA reductase and ACE inhibitor therapy

OBJECTIVES

Accelerated atherosclerosis is associated with herpesviral infection both in transplant patients and after balloon angioplasty. Marek's disease virus (MDV) is a herpesvirus that induces accelerated atherosclerosis associated with the development of an invasive lymphoma in hyperlipemic roosters. We have examined the effects of pravastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A (HMGCoA) reductase inhibitor and quinapril, an angiotensin converting enzyme (ACE) inhibitor, on atherosclerosis development in MDV infected, cholesterol fed rooster chicks.

METHODS

The effects of these drugs on plaque growth after MDV infection were examined in two studies. In Study 1, MDV infected White Leghorn rooster chicks were divided into 4 groups assigned to normal or high cholesterol diet, and treated at three months of age with either pravastatin or saline. In Study 2, cholesterol fed rooster chicks infected with MDV were divided into 3 groups for treatment with either pravastatin, quinapril, or saline control.

RESULTS

A significant decrease in plaque area was detected after 60 days of treatment with both pravastatin and quinapril in cholesterol fed chicks (P < 0.001). Lymphocyte infiltration into the arterial wall or target organs was not inhibited by treatment with either drug.

CONCLUSIONS

(1) HMGCoA reductase inhibitor and ACE inhibitor therapy reduce atherosclerosis induced by virus infection and cholesterol diet, but this decrease in plaque growth is not due to a reduction in lymphocyte invasion. (2) MDV infection in cholesterol fed roosters provides a model for virus-induced arterial injury in atherogenesis.

Consistent chromosomal aberration in cell lines transformed with Marek's disease herpesvirus: evidence of genomic DNA amplification

A specific chromosomal aberration was observed in 14 of 15 avian lymphoblastoid cell lines transformed with Marek's disease herpesvirus. This aberration, designated dup(1p)(p22-p23), appeared as an extra G-positive band and interband on the short arm of one chromosome I homolog. Using fluorescent in situ hybridization, we identified amplified genomic DNA sequences in this region. This amplification involves sequences linked to an endogenous retrovirus locus and genes in the histone multigene family. This aberration was not observed in cells transformed by reticuloendotheliosis virus or by avian leukosis virus, nor has it been observed in untransformed chicken cells. The induction of the 1p+ chromosomal aberration may be an essential event in the transformation of lymphocytes by Marek's disease virus.

Use of a soluble tetrazolium/formazan assay for chicken cells

We evaluated a soluble tetrazolium/formazan assay using 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl ]-2H- tetrazolium hydroxide (XTT) for chicken cell growth. Fifty microliter of solution containing 1 mg/ml of XTT and 0.025 mM phenazine methosulfate was added to the cells in a well of 96-well microplate. After 4 hr incubation at 37 degrees C, the absorbance was measured at 490 nm. Under this condition, absorbances were well correlated with cell number of Marek's disease tumor cells and chicken embryo fibroblasts. Proliferation of chicken lymphocytes stimulated with mitogens was also effectively measured. The formazan of XTT is water-soluble and can be quantitated in culture medium without the necessity for extraction with organic solvents. Thus XTT assay is simple and useful for the quantity assay with chicken cells.

Transgenerational epigenetic inheritance and immunity in chickens that vary in Marek's disease resistance

Marek's disease virus (MDV), a naturally oncogenic, highly contagious alpha herpesvirus, induces a T cell lymphoma in chickens that causes severe economic loss. Marek's disease (MD) outcome in an individual is attributed to genetic and environmental factors. Further investigation of the host-virus interaction mechanisms that impact MD resistance is needed to achieve greater MD control. This study analyzed genome-wide DNA methylation patterns in 2 highly inbred parental lines 63 and 72 and 5 recombinant congenic strains (RCS) C, L, M, N, and X strains from those parents. Lines 63 and 72, are MD resistant and susceptible, respectively, whereas the RCS have different combinations of 87.5% Line 63 and 12.5% Line 72. Our DNA methylation cluster showed a strong association with MD incidence. Differentially methylated regions (DMRs) between the parental lines and the 5 RCS were captured. MD-resistant and MD-susceptible markers of DNA methylation were identified as transgenerational epigenetic inheritable. In addition, the growth of v-src DNA tumors and antibody response against sheep red blood cells differed among the 2 parental lines and the RCS. Overall, our results provide very solid evidence that DNA methylation patterns are transgenerational epigenetic inheritance (TEI) in chickens and also play a vital role in MD tumorigenesis and other immune responses; the specific methylated regions may be important modulators of general immunity.