非洲猪瘟病毒p62蛋白单克隆抗体的制备及初步应用

为制备非洲猪瘟病毒（ASFV）p62蛋白的特异性单克隆抗体,并初步应用于感染组织样品中ASFV抗原的免疫组化（IHC）检测,本研究以杆状病毒表达的非洲猪瘟病毒重组p62蛋白免疫BALB/c小鼠,取其脾细胞与骨髓瘤细胞进行融合获得杂交瘤细胞。结果显示：基于纯化的p62蛋白建立的间接ELISA方法对杂交瘤细胞进行筛选和亚克隆,获得了18株可稳定分泌抗非洲猪瘟病毒p62蛋白单克隆抗体的杂交瘤细胞株。经IFA检测,制备的单克隆抗体均与非洲猪瘟病毒反应,且不与猪瘟病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪圆环病毒2型等猪源常见病毒反应,特异性良好。抗体识别蛋白的鉴定结果显示,3株MAbs识别p35蛋白,15株MAbs识别p15蛋白。14株MAbs重链亚类为IgG1型,4株MAbs重链亚类为IgG2a,轻链均为κ链。利用18株MAbs对ASFV感染猪的肺、扁桃体、淋巴结等组织进行IHC检测,结果显示5株MAbs均能够与感染ASFV的组织发生特异性的免疫反应。本研究获得的非洲猪瘟病毒p62蛋白单克隆抗体可为非洲猪瘟病毒免疫学检测方法的建立及p62蛋白的结构功能等基础研究提供重要的生物材料。     

非洲猪瘟病毒p62蛋白单克隆抗体的制备及初步应用

为制备非洲猪瘟病毒(ASFV)p62蛋白的特异性单克隆抗体,并初步应用于感染组织样品中ASFV抗原的免疫组化(IHC)检测,本研究以杆状病毒表达的非洲猪瘟病毒重组p62蛋白免疫BALB/c小鼠,取其脾细胞与骨髓瘤细胞进行融合获得杂交瘤细胞。结果显示:基于纯化的p62蛋白建立的间接ELISA方法对杂交瘤细胞进行筛选和亚克隆,获得了18株可稳定分泌抗非洲猪瘟病毒p62蛋白单克隆抗体的杂交瘤细胞株。经IFA检测,制备的单克隆抗体均与非洲猪瘟病毒反应,且不与猪瘟病毒、猪繁殖与呼吸综合征病毒、猪伪狂犬病病毒、猪圆环病毒2型等猪源常见病毒反应,特异性良好。抗体识别蛋白的鉴定结果显示,3株MAbs识别p35蛋白,15株MAbs识别p15蛋白。14株MAbs重链亚类为IgG1型,4株MAbs重链亚类为IgG2a,轻链均为κ链。利用18株MAbs对ASFV感染猪的肺、扁桃体、淋巴结等组织进行IHC检测,结果显示5株MAbs均能够与感染ASFV的组织发生特异性的免疫反应。本研究获得的非洲猪瘟病毒p62蛋白单克隆抗体可为非洲猪瘟病毒免疫学检测方法的建立及p62蛋白的结构功能等基础研究提供重要的生物材料。     

单克隆抗体间接免疫荧光检测猪瘟病毒方法的建立

以作者制备的抗猪瘟病毒单克隆抗体(anti-CSFV McAb)为一抗、荧光素标记羊抗小鼠IgG为二抗,通过反应条件的优化,建立检测猪瘟病毒抗原的间接免疫荧光(IFA)检测方法。确定IFA最佳工作条件:CSFV最佳接种浓度和培养条件为CSFV 10-3倍稀释后接种PK15细胞,37℃5%CO2恒温箱中培养36 h;McAb最适工作浓度为1∶1 000倍稀释;荧光素标记的羊抗小鼠IgG荧光抗体的最适工作浓度为1∶50倍稀释。特异性试验表明,用建立的IFA检测方法检测CSFV感染PK15细胞为阳性,而检测伪狂犬病病毒(PRV)、猪细小病毒(PPV)、猪2型圆环病毒(PCV-2)感染PK15细胞均为阴性。结果表明,建立的检测细胞培养中CSFV抗原的IFA检测方法具有敏感特异、简便快速等优点,可用于CSFV感染的实验室诊断及CSFV在感染细胞中的定位和动态分布研究。     

分泌抗猪繁殖与呼吸障碍综合征病毒单克隆抗体杂交瘤细胞株的制备与鉴定

用纯化的猪繁殖与呼吸障碍综合征病毒(PRRSV)免疫Balb／c小鼠，应用淋巴细胞杂交瘤技术．取脾细胞与NSn骨髓瘤细胞融合，经间接ELISA筛选，3次有限稀释法克隆，得到1株能稳定分泌抗猪繁殖与呼吸障碍综合征病毒单克隆抗体的杂交瘤细胞株：6Pg。经鉴定，该单抗为IgG1亚类，杂交瘤细胞的平均染色体数目为99条，杂交瘤细胞培养上清及小鼠腹水单克隆抗体的ELISA效价分别为1：256和1：20480。经Western-blot鉴定为针对N蛋白的单抗。6Pn株单克隆抗体与伪狂犬病毒、猪瘟病毒、猪细小病毒均不发生交叉反应，显示出良好的特异性。连续培养20代后能稳定分泌抗体。此单克隆抗体的获得为PRRSV的研究及快速诊断方法的建立奠定了基础。     

PCV2感染性分子克隆的制备及体内外感染性试验

将猪圆环病毒2型（Type2 porcine circovirus，PCV2）JXL株cDNA插入到载体pMD18-T中，获得的pMDT-PCV转染猪肾细胞PK15细胞系，盲传4代后，利用PCV2阳性猪血清进行间接免疫荧光抗体试验（IFA），能检测到特异性荧光。将pMDT-PCV质粒DNA腹股沟淋巴结注射40日龄仔猪2头，分别接种2、3次，接种剂量500μg／次，首次注射35d心脏放血致死。在体内感染性试验期间，动物未出现明显临床症状。试验结束，病理切片结果显示，不同淋巴组织中分别存在淋巴细胞缺失或增多的现象；肾小球、扁桃体、空肠淋巴结和股前淋巴结等冰冻组织切片中存在大量PCV2病毒抗原；血清中PCV2特异性的ELISA抗体效价迭1：2560，IFA效价为1：1280；通过聚合酶链式反应（PCR）可以分别从体外感染PK15细胞和体内感染动物及同圈饲养的空白对照猪的淋巴组织中扩增到病毒特异性基因片段。本研究证明含有单拷贝PCV2的重组质粒pMDT—PCV在体内、外均具有感染性，能衍生出病毒，并产生符合自然感染PCV2的大体病变和组织病理学变化，并激发较强的体液免癌应答。     

检测伪狂犬病病毒双抗体夹心间接ELISA方法的建立与应用

以猪伪狂犬病病毒（PrV）Ea株特异性单克隆抗体576株为捕获抗体，纯化的抗PrV IgG为检测抗体，建立了检测PrV抗原的双抗体夹心ELISA方法。最佳反应条件为，单克隆抗体576株的包被浓度为12．2μg／mL，IgG的工作浓度为16．0μg／mL，对PrV的检测灵敏度达15．6ng（0．156μg／mL），与乙型脑炎病毒（JEV）、猪瘟病毒（HCV）、猪繁殖与呼吸障碍综合征病毒（PRRSV）、猪细小病毒（PPV）和猪流感病毒（SIV）等无交叉反应。批间和批内变异系数较小，分别为6．39％和4．1％。应用本方法对人工感染PrV的40日龄仔猪组织进行检测，肺和脑PrV抗原检出率最高，其次是脾、心、肝和肌肉。应用该方法和PrV对159份临床样本进行平行检测，发现二者的符合率可达到77．4％，比PCR敏感。实验结果表明：双抗体夹心间接ELISA方法具有敏感性高、特异性强和重复性好的特点，可广泛应用于动物组织中PrV的检测。     

猪δ冠状病毒胶体金试纸条检测方法的建立

为建立一种方便、快捷、实用的检测猪δ 冠状病毒(PDCoV)方法,本研究利用原核表达猪δ 冠状病毒N 蛋白,以纯化的N 蛋白免疫BALB/C小鼠,利用杂交瘤细胞技术研制2株分泌PDCoV N 蛋白单克隆抗体的杂交瘤细胞株,分别命名为E8、A10。2株杂交瘤细胞分泌单克隆抗体敏感性及特异性良好,E8亚类为IgG2a,A10亚类为IgG1。以E8作为金标抗体,A10作为检测抗体,兔抗鼠作为质控线抗体,制备猪δ 冠状病毒胶体金检测试纸条,检测猪δ 冠状病毒敏感性为100TCID50,检测猪流行性腹泻病毒、猪传染性胃肠炎病毒、猪瘟病毒、猪圆环病毒、猪δ 冠状病毒阴性对照均为阴性。本研究建立的胶体金试纸条检测方法敏感性及特异性良好。该检测方法的建立,为猪δ 冠状病毒(PDCoV)流行病学调查提供一种方法,同时为规模化养殖集团及基层兽医组织提供一种检测猪δ 冠状病毒产品。     

二甲基亚砜在猪瘟病毒培养中的应用

猪瘟病毒能在猪肾细胞和其它一些哺乳动物细胞内增殖。感染性最强的是PK15和ST等几株猪肾和猪睾丸细胞系[1]。本实验室保存的ST细胞株易形成复层,长时间培养形成组织块突起,细胞团易脱落,无法长期连续收获猪瘟病毒。二甲基亚砜(DMSO)不仅可以影响细胞代谢促进蛋白合成[2]而且DMSO对猪瘟病毒囊膜中的脂质和脂蛋白有稳定作用[1]。     

猪圆环病毒1型阴性的PK-15细胞株的筛选

PK15是猪肾传代细胞系,其父母代源自1955年美国Stice提供的成年猪肾细胞PK2a,后被美国ATCC收藏(收藏号为ATCCCCL33)[1].PK15细胞现已广泛应用于猪瘟病毒、猪伪狂犬病病毒、猪细小病毒等的分离、体外增殖以及多种兽用疫苗的生产.     

猪繁殖与呼吸综合征病毒单克隆抗体的制备和鉴定

目的制备抗猪繁殖与呼吸综合征病毒(PRRSV)单克隆抗体并对其生物学特性进行鉴定。方法以纯化的PRRSV全病毒抗原免疫BALB/c小鼠,通过杂交瘤技术制备单克隆抗体,并测定其免疫球蛋白亚类、效价和特异性。结果成功获得2株能稳定分泌抗PRRSVM蛋白的单克隆抗体杂交瘤细胞,命名为3C3、3D2,经鉴定亚类均为IgG2a、kappa链。2株单克隆抗体腹水ELISA效价达105～107,IPMA效价达1:2560～1:10240,与猪瘟病毒、猪伪狂犬病毒、猪细小病毒、猪圆环病毒等无交叉反应。结论获得特异性针对猪繁殖与呼吸综合征病毒的单克隆抗体,为研究该病的快速诊断技术奠定基础。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.