Are the two polymorphic sites of anti-Marek’s disease in White Leghorn chickens also suitable for Partridge Shank chickens?

Background:The selection of Marek’s disease(MD)-resistant breeds in Partridge Shank chicken,a popular local chicken breed in Henan Province of China,has practical value.We hypothesized that the two polymorphic sites(rs14527240 located in SMOC1 and GGaluGA156129 located in PTPN3)related to MD resistance in White Leghorn chickens are also applicable to Partridge Shank chickens.Methods:In this experiment,we screened 10 live hens and 2 live roosters with the double GG genotype by genotyping the two sites from 6500 Partridge Shank chickens.Nineteen one-day-old chicks with the double GG genotype were obtained by artificial insemination.Seventy-two one-day-old chickens(19 from the population expansion test and 53 randomly selected from chicken farms)were injected with 2000 plaque-forming units of the Md5 virus strain.After 100 days of infection,all chickens were examined by pathological anatomical examination,histological sectioning,genotyping,and a quantitative polymerase chain reaction of SMOC1 and PTPN3.Results:There was only one site(rs14527240 located in SMOC1)associated with MD in Partridge Shank chickens(p<0.05),but the GG genotype of SMOC1 in Partridge Shank chickens indicated susceptibility to MD.SMOC1 expression in MD-susceptible chickens was also significantly higher than that in MDresistant chickens(p<0.05).Conclusion:Therefore,the MD resistance sites selected from White Leghorn chickens were not completely suitable for Partridge Shank chickens,but they can be used as a reference.This study indicated that SMOC1 plays an important role in screening for MD resistance in poultry.

St udy on Hsp90 Expression in Different Tissues and Its Antibody in Serum of Chickens Infected with Marek's Diseases

To investigate the dynamic change of heat shock protein 90 （Hsp90） in the genesis and development of tumor, we successfully established tumor animal model using Marek’s disease and then determined the location of Hsp90 in the tumor tissue using immunohistochemistry method, the antibody titer level of Hsp90 in the serum and the expression level in the tissue using enzyme-linked immunosorbent assay （ELISA） method. Our result showed that Hsp90 location in the tumor tissue was signiifcantly associated with the tumor cell and most in the cytoplasm of the tumor cell, and Hsp90 expression level in the tissue and the antibody titer level in the serum was most signiifcantly increased with the development of tumor. This is the ifrst report to show the presence of Hsp90 in tumor tissues induced by the Marek’s disease, with its expression correlated to the tumoral grading. These data may also be valuable for developing new molecular anti-cancer therapies.

Dynamic Pathology and Antigen Location Study on Broiler Breeders with Coinfection of Marek's Disease Virus and Reticuloendotheliosis Virus

To further understand the generation and development of coinfection of Marek＇s disease virus （MDV） and reticuloendotheliosis virus （REV） in broiler breeders, and then find the method and optimal time of differential diagnosis for complex clinic multiple infection, the authors studied the pathohistological changes, apoptosis, immunohistochemistry （immunofluorescence）, and ultrastructure of tumor tissues of broiler breeders inoculated with MDV and REV. The study showed that proliferation of small lymphocytes was seen in the main organs at the age of 1 week, then immature lymphocytes, all kinds of lymphocytes, primitive reticulum cells, and Marek＇s disease cells （MDCs） were observed at 2-9 weeks. Apoptosis of lymphocytes could not be seen until the age of 10 weeks in the immune system. Immunohistochemistry detection showed that the positive signs of MDV and REV antigen were observed in the main organs at 2 weeks of age. Multi-morphology lymphocytes, MDV, and REV, mitotic figures and apoptosis of lymphocytes were observed with the help of transmission electron microscopy. MDV cooperating with REV promotes the course of disease of coinfection. Differential diagnosis can be done by immunohistochemistry in the early stage （before 2 weeks）, and histopathology in the late stage （post 4 weeks）. MDCs, primitive reticulum cells, immature lymphocytes, and two kinds of virions can serve as a basis for bistopathology differential diagnosis.

Vaccine by Chicken Line Interaction Alters the Protective Efficacy against Challenge with a Very Virulent plus Strain of Marek’s Disease Virus in White Leghorn Chickens

Marek’s disease (MD) is a lymphoproliferative disease of domestic chickens caused by Marek’s disease virus (MDV), an oncogenic and highly contagious α-herpesvirus. MD has been controlled by vaccination but sporadic outbreaks of MD still occur in some parts of the world. Efforts to improve vaccine efficacy have continued in both research communities and vaccine industries. We reported the host genetic variation affecting Marek’s disease vaccine-induced immunity in chickens earlier. In this study, we evaluated chicken lines, vaccines, and line by vaccine interaction on the protective efficacy of vaccination against MD. Specific pathogen free chickens from the relatively resistant line 63 and the highly susceptible line 72 were primarily used to evaluate the protection by three kinds of vaccines (rMd5ΔMeq, CVI988/Rispens, and HVT) upon challenge with a very virulent plus strain of MDV, vv+648A. Our data confirmed that both the chicken line and the vaccine significantly affected the protective efficacy of vaccination and showed that a chicken line by vaccine interaction, in most of the trials, also altered vaccine protective efficacy. More interestingly, although the protective index of all vaccine strains was higher in resistant than in susceptible line of chickens, the difference for HVT protection was striking and warrants further study. The findings may have important implications for vaccine development as well as for selective use of particular vaccines in specific lines of chickens to achieve maximum protection at minimized costs.

Molecular Cloning and Sequencing of a Specific cDNA Mapping to the Bam HI-I2 and -LFragments within the Inverted Repeats of Unique Long Region(IRL) from the Genom e of the Marek′s Disease Herpesvirus (MDV) Oncogenic Strain Beijing-1

Isolation and identification of a specific cDNA mapping to the BamHI I2 and L fragments from the inverted repeats of unique long region(IRL) in the genome of Marek′s disease herpesvirus (MDV) oncogenic strain Beijing 1 had been previously performed by us. In this study, the specific cDNA was cloned into phagemid vectors PUC118 and 119 on the basis of prefabricated two recognized sites in synthesized primers. Recombinants were further identified with restriction pattern, molecular hybridization, and DNA sequencing analysis. It was demonstrated that this cDNA with 720 base pair (bp) contained sequences including a potentially incomplete open reading frame (ORF) encoded a 238 amino acids (aa) predicted polypeptide which was significantly homologous not only to part of N terminus of meq, but also to that of XbaI ClaI subfragment of BamHI L. In accordance with these data, following results could be deduced:①the 720 bp cDNA represented a spliced transcript;②meq transcription could be extended from the right hand end of BamHI I2 to the adjacent BamHI L fragment;③the L region was transcribed in varying degrees\ in MDV induced lymphoblastoid tumors.

Knockdown of the Meq gene in Marek’s disease tumor cell line MSB1 might induce cell apoptosis and inhibit cell proliferation and invasion

Marek’s disease(MD),a highly cell-associated and contagious disease of chickens caused by Marek’s disease virus(MDV)can result in neural lesions,immunosuppression and neoplasia in chicken.The Meq gene is an important oncogene in the MDV genome,and it is expressed highly in MD tumor tissues and MD T-lymphoblastoid cell lines.An experiment was conducted to elucidate the role of Meq in MD tumor transformation.RNA interference technology was used to block its expression,and then analyzed the biological effects of Meq knockdown on the MD tumor cell line MSB1.A small interfering RNA with an interference efficiency of 70%(P<0.01)was transfected into MSB1 cells to knock down the expression of Meq gene.The cell proliferation,cycle and apoptosis were detected post-Meq knockdown.The results showed that MSB1 cell proliferation was downregulated remarkably at 48 h(P<0.01),60 h(P<0.05)and 72 h(P<0.01)post-Meq knockdown.The cell cycle was unaffected(P>0.05).B-cell lymphoma 2 gene(BCL2)was anti-apoptotic and caspase-6 was the effector in the apoptosis pathway.The activity of caspase-6 was upregulated(P<0.05)significantly and BCL2 gene expression was downregulated(P<0.05)significantly post-Meq knockdown,suggesting cell apoptosis might be induced.MSB1 cell migration did not exhibit any obvious change(P>0.05)post-Meq knockdown,but the expression of two genes(matrix metalloproteinase 2(MMP2)and MMP9)that are correlated closely to cell invasion was downregulated(P<0.05)remarkably post-Meq knockdown.The Meq knockdown might affect the main features of tumorous cells,including proliferation,apoptosis,and invasion,suggesting that the Meq gene might play a crucial role in interfering with lymphomatous cell transformation.

洛阳市郊区四个鸡场鸡马立克氏病(MAREK′S DISEASE)诊断报告

一、引言 鸡马立克氏病(MD)在我省的检出是1978年3月我们对三只仙居鸡进行了大体剖检和组织学检查之后确诊的。之后79年元月在处理牧场病残鸡时又检出了数只。1981年许昌地区畜牧兽医工作站报道了许昌某鸡场MD暴发的情况。1981年11月我们又在洛阳市郊区四个鸡场检出MD病鸡。仅将洛阳市郊MD诊断结果报告于后。 二、诊断方法 1、群检:在四个鸡场中任选1——2圈鸡群进行视检,从中挑出弱病鸡备检。 2、在上述挑出的备检鸡中随机取若干鸡,从翅、腋下、胸部拔取新鲜羽毛6根。

Cloning and Identification of L-meq Gene of Marek's Disease Virus

[Objective]To clone and identify Marek＇s disease virus （ MDV） serum gene. [Method]MDV genomic DNA was extracted from lymphoid tissues of the diseased chickens with latent MDV infection. The MDV L-meq gene was amplified by gradient PCR,inserted into pMD18-T vector and sequenced. The sequence was analyzed using DNAman software. [Result] The obtained sequence had 100% similarity with the published se- quence of L-meq gene,showing successful amplification of target gene. [Conclusion]The paper provides new ideas and new methods for preven- tion and treatment of Marek＇s disease in chickens.

Marek’s disease virus challenge induced immune-related gene expression and chicken repeat 1 (CR1) methylation alterations in chickens

Marek’s disease virus (MDV) challenge induces lymphoma in susceptible chickens. Host genes, especially immune related genes, are activated by the virus. DNA methylation is an epigenetic mechanism that governs gene transcription. In the present study, we found that expression of signal transducer and activator of transcription 1 (STAT1) was upregulated at 10 days post infection (dpi) in MD susceptible chickens, whereas interleukin 12A (IL12A) was elevated in both resistant and susceptible chickens. However, we did not observe MDV-induced DNA methylation variations at the promoter CpG islands (CGIs) in STAT1 and IL12A. Interestingly, the methylation levels at Chicken Repeat 1 (CR1), the transposable elements (TEs) located upstream of two genes, were different between resistant and susceptible chickens. Furthermore, a mutation was identified in the CR1 element near IL12A. The impact of the point mutation in transcriptional factor binding is to be examined in the near future.

Comparison of Immune Effect of Four Commercial Marek's Disease Vaccines in Wenchang Chicken

Marek＇s disease（MD） is a lymphoproliferative disease of domestic chickens caused by a highly infectious,oncogenic alpha-herpesvirus known as Marek＇s disease virus（MDV）.The aim of this study was to compare the efficacy of four commercial MDV vaccines in Wenchang chicken.The 1-day old Wenchang chickens tested were injected with one of four different vaccines or not unvaccinated as control;five days later,they were then challenged by virulent MDV strain MD5.The results showed that,in comparison with HVT vaccines,the CVI988 vaccine gave the immunized chickens more potent immunities against challenges of MDV strain MD5.

基于高分辨率熔解曲线检测MD肿瘤微卫星不稳定性

本研究旨在通过高分辨率熔解曲线(high-resolution melting,HRM)方法检测马立克病(Marek′s disease,MD)肿瘤中存在的微卫星不稳定现象(microsatellite instability,MSI)。通过临床症状、病理剖检、组织病理学、PCR及测序确定为马立克病。采集5只发病鸡的肌肉、肝、脾、血液及肿瘤组织,提取DNA,采用15对扩增微卫星DNA序列的引物进行HRM检测,得到归一化处理的差异熔解曲线,比较分析各组织熔解曲线的差异,分析15个微卫星标记是否存在基因突变(即MSI)。结果表明,发病鸡的各种临床、病理表现符合为马立克病的特征,病毒meq基因序列与近年来国内流行的MDV强毒株有较高的同源性。HRM分析结果显示,MD发病鸡的肌肉、肝、脾、血液、肿瘤组织中微卫星标记PCR扩增后的熔解曲线存在明显的差异,即存在MSI现象,而且不同的病鸡个体和不同的微卫星标记发生MSI的频率不同。15个微卫星标记在5只鸡的病料中存在MSI的微卫星标记的个数分别为14、7、5、3和1。在15个微卫星标记中,MCWO200、MCW0220这两个微卫星标记在所有的病鸡中都存在MSI,而ADL0158微卫星标记在所有的病鸡中都不存在MSI。通过非变性聚丙烯酰胺凝胶电泳和测序分析进一步证明这些微卫星PCR扩增片段确实存在片段大小不同,碱基序列中存在微卫星重复单位的增多、减少或基因片段的插入或缺失。结果提示,通过HRM分析可以检测MD肿瘤中的MSI现象,是一种灵敏、准确、简便、高通量的方法。

人参皂苷Rh_2对MSB-1细胞的增殖抑制作用及其机理

以不同质量浓度的人参皂苷Rh2与马立克氏病肿瘤细胞系MSB-1细胞共同作用,利用改良MTT法测定了人参皂苷Rh2对MSB-l细胞的增殖抑制作用,并通过流式细胞术、荧光检测和电镜形态学观察等方法探讨其抑制机理。结果显示:人参皂苷Rh2对MSB-l细胞的增殖存在抑制作用,并呈剂量依赖性,人参皂苷Rh2与MSB-1细胞培养72 h后的半数抑制质量浓度为0.65 mg/L;流式细胞术测定表明,人参皂苷Rh2可阻滞MSB-1细胞于S期;荧光检测和透射电镜观察表明,人参皂苷Rh2可以诱导部分MSB-1细胞发生凋亡。

重组马立克病病毒CVI988／Rispens的构建

根据I型马立克病病毒(MDV)强毒GA株基因序列,设计两对引物,用PCR方法扩增出CVI988／Rispens株的US10及其侧翼序列,分别克隆入pUC18载体中。经测序检测正确后,进一步插入含CMV启动子的绿色荧光蛋白 (EGFP)基因表达盒,获得了含EGFP报告基因的转移载体质粒pPUC18-US10-EGFP。通过同源重组,成功地筛选出表达EGFP的重组病毒rCVI988-EGFP,经传代证明重组rCVI988-EGFP在感染的CEF细胞中能稳定表达EGFP。结果表明:构建的重组转移载体质粒正确,US10是MDV复制非必需片段,为进一步利用US10区构建重组MDV多价基因工程疫苗奠定了基础。

用 Western Blot 法鉴定感染鸡外周血淋巴细胞中马立克氏病毒抗原

马立克氏病毒是鸡的一种高度致肿瘤性疱疹病毒，主要以淋巴瘤为特征，有关该病毒的致病机理还不清楚。本研究利用澳大利亚分离的ＭＤＶ致病毒株ＭＰＦ５７感染１日龄ＳＰＦ雏鸡，并在感染后４周对其外周血淋巴细胞中的ＭＤＶ特异性抗原进行了检测。结果表明，临床上呈急性感染并伴有明显症状的鸡的外周血淋巴细胞中的ＭＤＶ抗原分子量主要为２８、７３、６０和４９ｋＤａ；而无明显症状的鸡的外周血淋巴细胞中的ＭＤＶ抗原分子量主要为７３ｋＤａ。试验证明，Ｗｅｓｔｅｒｎｂｌｏｔ是一种较好的检测病毒抗原的方法，可以检测到荧光抗体方法检测不到的淋巴细胞中的ＭＤＶ特异抗原。

MDV Rispens 株B抗原基因的酶切及序列分析

将马立克氏病病毒（ＭＤＶ）血清Ｉ型Ｒｉｓｐｅｎｓ株接种原代鸡胚成纤维细胞（ＣＥＦ），待出现８０％以上细胞病变后收获，提取细胞和病毒的总ＤＮＡ．以此为模板，根据Ｂ抗原基因核苷酸序列设计一对引物，通过聚合酶链反应（ＰＣＲ）扩增出一条约２．８５ｋｂ的特异性条带，双酶消化后克隆至质粒ｐＵＣ１９，酶切分析表明该病毒的Ｂ抗原基因上ＨｉｎｄⅢ、ＥｃｏＲⅤ、ＢａｍＨⅠ、ＥｃｏＲⅠ的酶切位点分布与ＲＢ１Ｂ株、ＧＡ株的完全相同，进一步序列分析表明。

鸡马立克氏病CVI988/Rispens毒株生物学特性的研究

对荷兰农业渔业部提供的初代次 CVI988/ Rispens种毒 ,繁殖到 37代 ,用间接荧光抗体试验测定属血清 型 ,经接种雏鸡进行 6代毒力返强试验观察到 70日龄和对 1日龄雏鸡接种 4 5 0 0 0个蚀斑单位 ,观察到 12 0日龄均为安全。对 1日龄雏鸡接种免疫剂量的疫苗 ,于 4日龄产生病毒血症 ,7～ 14日龄达到高峰。用 37代毒繁殖生产的三批 CVI988/ Rispens疫苗 ,与国外 CVI988/ Rispens疫苗进行免疫效力比较 ,保护指数为 94 .5 %～ 10 0 %。

Expression and intercellular trafficking of the VP22 protein of CVI988/Rispens vaccine strain of Marek’s disease virus

The viral protein 22 (VP22) in the tegument of Marek’s disease virus serotype 1 (MDV-1) plays an im-portant role in cell-to-cell spread and viral propagation. Antiserum against the carboxyl terminus of VP22 was prepared by immunizing mice with recombinant VP22 expressed in E. coli, and used to in-vestigate its expression in chicken embryo fibroblast (CEF) cells infected with different MDV-1 strains. At an infection dose of PFU=50, intercellular trafficking of the VP22 into the nuclei of the surrounding receipt cells was detected as early as 3 hours post infection. By 6 hours after infection (before viral plague formation), the protein was detected in the whole nuclei of the recipient cells with no difference among MDV-1 strains CVI988/Rispens, GA and RB1B. Intra-nuclear accumulation of the VP22 protein was further increased when the viral plagues started to form. These results indicate that, albeit the ex-istence of the 201TKSERT206 deletion, the VP22 of the CVI988/Rispens vaccine strain has also intercel-lular-trafficking function, which might serve as a potential alternative delivering protein instead of virulent strains VP22.

Analysis of DNA methylation of CD79B in MDV-infected chicken spleen

Marek’s disease(MD),an immunosuppressive disease induced by Marek’s disease virus(MDV),provides an ideal model for studying diseases caused by a carcinogenic virus.CD79 B is a B-cell antigen receptor complex-associated protein β-chain precursor which is involved in the activation,proliferation,differentiation of B-cell and the transmission of downstream signals.This study analyzed CD79 B gene mRNA expression and methylation by two schemes#20(5′flanking to intron 1)and#27(intron 2 to intron 3),between MDV-infected tumorous spleens(TS)and non-infected spleens(NS).Results showed that average methylation levels of CpGs in #20 and #27 were higher in TS than in NS(P<0.05),while,CD79 B mRNA expression was lower in TS than in NS(P<0.01).Six of 40 CpG sites showed significantly(P<0.05)different methylation levels between TS and NS.Correlation analysis showed that the average methylation level rather than a single site methylation level in #20 affected(P<0.05)mRNA expression.Collectively,it was found that the change of CD79 B gene expression after MDV infection might be partly explained by modification of DNA methylation.

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 investi-gate 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 pro-moter 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. The transfection shows the promoter has the complete activity under the condition of co-expression of pp38 and pp24 in the same cells. Immunoprecipitation test was used to verify the structure of pp38/pp24 heteropolymer. The pp38-specific monoclonal antibody H19 was used in this test, and pp38, pp24 or both were prepared from the pcDNA-pp38, pcDNA-pp24 or pBud-pp38-pp24 transfected chicken embryonic fibroblast (CEF), respectively. Immunoprecipitation indicates that pp24 could be co-precipitated with pp38 by MabH19, implying that pp24 and pp38 were able to form a heteropolymer in the natural condition. The two separated tests clarify that pp38 and pp24 form a heteropolymer, which enhances the activity of the promoter.

Relationship between Tumor Lesion of Kidney Tissue and Expression of HSP60 in Chickens Infected by MD

[ Objective] The paper was to investigate the relationship between pathological lesion and transcription, expression and distribution of heat shock protein 60 （HSP60） in kidney of chickens infected by Marek＇s disease virus （MDV）. [ Method] Tumor animal model was successfully established with chickens infected by MDV. Real-time RT-PCR, histopathological and immunohistochemistrical methods were used to detect the pathological lesion, transcription level, expression level and distribution of HSP60 in the kidney. [ Result] Obvious pathological changes appeared in kidney tissue of chicken after injection of MDV for 21 d. HSP60 was mainly distributed in the cytoplasm of tumor cell and interstitial macrophages. The expression of HSP60 in challenge group was always higher than blank control group and vaccine control group, and the difference reached extremely significant level from 28 to 86 day-ages （ P 〈 0.01 ） ; the expression of HSP60 in challenge group at 28 day-age was about 8.608 and 12.752 times of blank control group and vaccine control group, respectively. The mRNA transcription levels of HSP60 in challenge group showed a downward parabola during 7 to 42 day-ages; the mRNA transcription level of HSP60 in challenge group was rising in early stage （7 -21 d）, and then gradually dropped; it reached the peak value at 21 d, being 1.222 and 1.179 times of blank control group and vaccine control group, respectively. The mRNA transcription level of HSP60 was higher than two control groups throughout the entire experiment, and the difference reached extremely significant level from 14 to 28 day-agas （P 〈0.01 ）. [ Conclusion] HSP60 expression in kidney tissue and its mRNA transcription level can reflect MDV infection, tumor formation and development progress, with close relationship with pathogenesis of tumor diseases, which is expected to be used as one of the determination indicators for diagnosis and morbidity process of tumor diseases in chicken.