人参皂苷及其衍生物抗马立克氏病毒的作用

用马立克氏病毒(Marek′s disease virus,MDV)人工感染雏鸡为疾病模型,采取人参皂苷及其衍生物口服,通过间接免疫荧光试验动态观察人参皂苷及其衍生物能否减少MDV抗原在组织中的分布。结果人参皂苷组、衍生物组被检组织的阳性细胞数量明显比盐酸吗啉胍阳性对照组被检组织的阳性细胞数量少。表明人参皂苷及其衍生物抗MDV效果要优于盐酸吗啉胍。     

人参皂苷及其衍生物抗马立克氏病毒的作用

为探讨人参皂苷及其衍生物体外抗马立克氏病毒(MDV)的作用机理,采用空斑试验测定人参皂苷及其衍生物对马立克氏病毒感染鸡胚成纤维细胞(CEF)的保护效果,结果发现人参皂苷及其衍生物均具有较好的抗病毒效果,特别是人参皂苷衍生物组增殖抑制的抗MDV空斑减少率达到盐酸吗啉胍的77%(55.62/72.52)。表明人参皂苷及其衍生物可以减轻病毒对CEF细胞的损伤程度。     

人参皂苷及其衍生物体内抗鸡马立克氏病毒的病理组织学观察

为探讨人参皂苷及其衍生物体内抗马立克氏病毒的作用机理,试验用马立克氏病毒人工感染雏鸡模型,口服人参皂苷及其衍生物,动态观察雏鸡的组织病理学变化,并比较治疗组和病毒对照组的病变差异.结果人参皂苷和衍生物治疗组的组织结构病变程度均低于病毒对照组.说明人参皂苷及其衍生物可以降低病毒对组织的损害程度,增强雏鸡对病毒的抵抗力.     

细胞病变观察法检测人参皂苷及其衍生物抗马立克氏病病毒的作用

为探讨人参皂苷及其衍生物体外抗马立克氏病病毒的作用机理,采用体外细胞培养法,在药物安全浓度范围内,测定人参皂苷及其衍生物对马立克氏病病毒(MDV)感染鸡胚成纤维细胞(CEF)的保护效果。结果显示,修饰前的人参皂苷和修饰后的衍生物7具有较好的抗病毒效果。表明人参皂苷和衍生物7可以减轻病毒对CEF细胞的损伤程度。     

人参皂苷及其衍生物抗马立克病病毒作用的超微结构和病理变化观察

为了探讨人参皂苷及其衍生物抗马立克氏病病毒的作用机制.采用马立克氏病毒感染的雏鸡作为模型,人参皂苷及其衍生物口服给药途径,动态观察不同时间段,试验鸡的器官病理变化和脾脏、法氏囊的组织超微结构改变.结果发现人参皂苷及其衍生物组的器官病变程度明显低于病毒对照组,法氏囊和脾脏的超微结构病变轻于病毒对照组,说明人参皂苷及其衍生物在体内可以通过保护机体免疫器官来发挥抗病毒作用.     

人参总皂苷及其衍生物抗Ⅰ型马立克氏病毒作用的电镜观察

应用透射电镜负染技术，观察人参总皂苷及其衍生物对Ⅰ型马立克氏病毒（MDVI）作用后病毒颗粒结构改变情况，旨在深入探讨人参总皂苷及其衍生物抗MDV的作用机理。结果显示，病毒颗粒变形，大小不均匀．核心缺损或均质化，包膜裸露或破损以及病毒颗粒凝集融合成块，结构模糊不清。在相同条件下衍生物比人参总皂苷对MDV的破坏作用强。提示人参总皂苷及其衍生物在体外对MDVⅠ（MDV—Ⅰ）病毒颗粒的形态结构、表面成分和分散均有破坏作用，而衍生物作用更加显著。     

马立克氏病毒感染鸡胚成纤维细胞模型的建立

用雏鸡将马立克氏病毒（MDV）血毒复壮,分离发病鸡淋巴细胞并接种于鸡胚成纤维细胞,观察其病变。获得适应鸡胚成纤维细胞（CEF）的MD强毒,通过电镜观察、琼脂扩散实验进一步鉴定病毒,并建立了MDV感染CEF细胞模型,为研究人参皂苷及其衍生物的体外抗病毒作用及其机制奠定基础。     

分子修饰前后人参皂苷体外抗马立克氏病毒鸡胚成纤维细胞模型的建立

用雏鸡将马立克氏病毒(MDV)血毒复壮,分离发病鸡淋巴细胞并接种于鸡胚成纤维细胞,观察其病变。获得适应鸡胚成纤维细胞(CEF)的MD强毒,通过电镜观察、琼脂扩散实验进一步鉴定病毒,并建立了MDV感染CEF细胞模型,为研究人参皂苷及其衍生物的体外抗病毒作用及其机制奠定基础。     

硫酸化人参总皂苷对人工感染MDV鸡淋巴细胞活性的调节

鸡马立克氏病病毒（MDV）经腹腔注射感染8日龄雏鸡,攻毒15 d后检测硫酸化人参总皂苷对鸡外周血白细胞数和淋巴细胞增殖活性的影响,并利用半定量RT-PCR方法分析外周血淋巴细胞IFN-γmRNA的表达水平。结果表明,MDV感染能引起鸡淋巴细胞百分比相对增多（P〈0.01）,人参总皂苷及其硫酸化人参总皂苷不能改变MDV所致变化（P〉0.05）,且硫酸化人参总皂苷与人参总皂苷之间没有差异（P〉0.05）;MDV感染极显著抑制淋巴细胞增殖（P〈0.01）,人参总皂苷能明显改善MDV对感染鸡淋巴细胞增殖的抑制（P〈0.01）,硫酸化人参总皂苷促进了MDV所致的抑制状态（P〈0.01）;人参总皂苷及其硫酸化人参总皂苷均能增强MDV所致鸡淋巴细胞IFN-γmRNA的表达,与健康组相比,硫酸化人参总皂苷极显著增加IFN-γmRNA表达（P〈0.01）。结果提示,硫酸化人参总皂苷对人工感染MDV鸡的淋巴细胞活性具有调节作用,其作用比人参总皂苷的作用更强。     

海兰商品蛋鸡白血病与马立克氏病混合感染案例分析

从临床流行病学、剖检症状、病理变化、马立克氏病、禽白血病、网状内皮组织增生症病毒特异基因的PCR检测等进行综合分析,以期对河南南阳地区某海兰蛋鸡场鸡群的疑似肿瘤疾病进行确诊。结果显示:鸡群大体正常,但零星出现死亡,死亡鸡极度消瘦,心、肝、脾、肺等脏器肿胀及个别病鸡脏器肿胀且有肿瘤结节。PCR检测结果显示:MDV阳性、ALV阳性、REV阴性,确诊鸡群感染马立克氏病病毒和禽白血病病毒。     

Vaccinal control of Marek's disease: current challenges, and future strategies to maximize protection

Marek's disease is an economically important lymphoid neoplasm of chickens, caused by oncogenic strains of Marek's disease herpesvirus. The disease can be successfully controlled by vaccination with attenuated or non-pathogenic MDV strains. However, vaccine failures do occur as field strains continue to evolve towards pathotypes of greater virulence, and this evolution is likely to be driven by the vaccines themselves. Two general strategies can be considered to improve protection by vaccination. Firstly by the development of novel vaccines, and secondly by maximizing the potential of existing vaccines. This second goal requires investigation of optimal timing and vaccine delivery route, and optimal vaccination regimes for different breeds of chick. Accurate quantitation of Marek's disease vaccine virus in vaccinated chicks will contribute significantly to our understanding of vaccinal protection. We recently developed a real-time polymerase chain reaction (PCR) assay for quantitation of CVI988 vaccine virus in the feather tips, a rich source of viral DNA which can easily be sampled in a non-invasive manner. This PCR test is now used commercially to confirm the successful vaccination of chicks. We have also used the PCR to examine various aspects of vaccination in experimental chicks and commercial chicks with a view to determining how vaccine level in feathers correlates with protection against challenge, and for identifying optimal timing and vaccine delivery route, and optimal vaccination regimes for different breeds of chick. In this article we review some aspects of the current vaccinal control of Marek's disease, before highlighting some of the problems associated with current vaccines and vaccination strategies, and the challenges for the future. We go on to discuss the development and use of our real-time PCR feather test, its current applications and potential opportunities in Marek's disease vaccine research.     

Marek's disease in turkeys. I. A seven-year survey of commercial flocks and experimental infection using two field isolates

Marek's disease virus (MDV) causes immunosuppression and tumors in chickens, but the turkey is an unusual host for the virus, and tumors caused by MDV in turkeys are unique. We describe the prevalence of turkey tumors in Israel between 1993 and 2000, their molecular diagnosis by polymerase chain reaction (PCR), and the natural distribution of herpesvirus of turkeys (HVT). Most clinical cases with tumors in commercial turkeys were diagnosed as MDV. The reproduction of Marek's disease (MD) in turkeys by two turkey MDV strains, Ar and La, was analyzed, and it was shown that these strains can induce tumors in experimental trials. The severity of experimental disease differed from those features of the original outbreak, since a less severe disease was recorded.     

Antibody directed against Marek's disease-associated tumor surface antigen can be eluted from Marek's disease tumor cells.

Antibody directed against Marek's disease-associated tumor surface antigen (MATSA) was eluted from tumor cells of lymphomas and peripheral blood lymphocytes that were isolated from Marek's disease virus-infected chickens. Feather follicular Marek's disease virus (MDV) antigen could not be demonstrated with this antibody by indirect immunofluorescent (IF) staining. Monoclonal antibody directed against MATSA could completely block the activity of eluted antibody and vice versa. By indirect IF staining using eluted antibody and fluorescein isothiocyanate (FITC) labelled antichicken globulin conjugate. MATSA-bearing cells were detected in MDV infected and herpes virus of turkey (HVT) vaccinated birds. Blocking of immunoglobulin molecules present on B-cells by anti-chicken globulin is critical in this test.     

Differentiation of oncogenic and nononcogenic strains of Marek's disease virus type 1 by using polymerase chain reaction DNA amplification.

Differentiation of oncogenic and nononcogenic strains of Marek's disease virus type 1 (MDV1) was attempted by polymerase chain reaction (PCR) using the primers chosen from the sequence within the long inverted repeats of MDV1 DNA. PCR of the DNAs extracted from oncogenic-strain-infected cells and Marek's disease tumor cell lines produced a major product containing two or three copies of 132-base-pair (bp) repeat units, whereas PCRs of the DNAs extracted from nononcogenic-strain-infected cells yielded amplified products with various sizes corresponding to the number of 132-bp repeat units. The primers chosen from the glycoprotein A genes of MDV1 and herpesvirus of turkeys also were used for determination of their serotype specificity. The PCR procedure was found to be a simple and sensitive procedure for identification of MDV1 and herpesvirus of turkeys and for estimation of oncogenicity of MDV1.     

通过雏鸡MDV攻毒试验选择抗马立克氏病亲本

对F0、F1、F2亲本经继代No.614血型基因选择后繁殖的F2、F3雏鸡,10日龄以马立克氏病强毒（MDV）攻击至60日龄的死亡率,其父母亲对No.614抗血清呈阳性反应的试验组显著低于其父母亲对此抗血清呈阴性反应的对照组。试验组25个家系中,有14个家系的F2雏鸡死亡率显著低于对照组;F3雏鸡有21个家系的死亡率低于对照组,其中8个家系具有统计意义。肿瘤发生率,以肾脏和腺胃最高,肺脏和神经组织最低。综合血型抗原检测和MDV攻毒结果,从试验组25个家系中选留强MDV抗性家系留种繁殖,继代选育。     

Embryo vaccination against Marek's disease with serotypes 1, 2 and 3 vaccines administered singly or in combination

Marek's disease virus (MDV) vaccines of serotypes 1 and 2 administered in 18-day-old embryonated eggs induced better protection against post-hatch challenge at 3 days with virulent MDV than vaccines given at hatch. Embryonal vaccination with a polyvalent vaccine containing equal quantities of serotypes 1 and 2 of MDV and serotype 3 virus (turkey herpesvirus, HVT) was also significantly more effective than post-hatch vaccination. These and earlier results indicate that protective efficacy of single or combined Marek's disease vaccine serotypes against post-hatch challenge at 3 days can be substantially improved if the vaccines are injected into 18-day embryos rather than at hatch. Injection of vaccines of serotypes 1 or 2 into embryonated eggs or hatched chicks did not cause detectable gross or microscopic lesions in chickens. Vaccine viruses of serotypes 1 and 2 could be isolated from spleen cells of chickens 1 week post-vaccination, and the titer of recoverable viruses was higher in chickens that received the vaccines at the 18th day of embryonation than in chickens vaccinated at hatch. Although embryo vaccination with HVT usually provided better protection than post-hatch vaccination against early post-hatch challenge with variant pathotypes of MDV, the protection was poor regardless of vaccination protocol. If challenge with variant pathotypes of MDV was delayed until embryonally or post-hatch HVT-vaccinated chickens were 21 days of age, protection of chickens by HVT was not enhanced. Thus, resistance induced by embryonal vaccination with HVT was qualitatively similar to that induced by post-hatch vaccination with this virus.     

山东省肉种鸡群三种家禽肿瘤性疾病流行病学调查

为调查山东省家禽肿瘤性疾病的流行情况,本研究以血清学、病理组织学、免疫组织化学、病原学等检测手段,在山东省境内17家AA种鸡场进行检测.血清学试验结果显示:马立克氏病病毒(MDV)平均抗原阳性率为1.87%;禽白血病病毒J亚群(ALV-J)和网状内皮组织增生症病毒(REV)平均抗体阳性率分别为9.52%和39.78%;双重及三重感染,MDV+ALV-J、MDV+REV、ALV-J+REV及MDV+ALV-J+REV感染率分别为1.12%、1.21%、3.92%和0.65%.对57羽疑似肿瘤病的病鸡检测显示:MDV、ALV-J和REV的抗体阳性率分别为19.3%、47.37%和57.89%;MDV+ALV-J、MDV+REV和ALV-J+REV的双阳性率分别为1.75%、3.5%和19.3%;无三重感染.病理组织学观察显示:病鸡体内既有各病毒引起的单纯肿瘤,也有双重肿瘤共存的现象.免疫组织化学检测显示,MDV、ALV-J和REV抗原阳性信号在病鸡中的比例分别为38.6%、54.39%和28.07%.PCR检测结果表明:MDV、ALV-J和REV的阳性率分别为43.86%、64.91%和33.33%;MDV+ALV-J、MDV+REV、ALV-J+REV和MDV+ALV-J+REV阳性率分别为15.79%、10.53%、12.28%和7.02%.本研究结果表明,山东省境内AA肉鸡群中仍存在较高的肿瘤性病毒感染率.