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1.
南京农业大学李祥瑞博士研制成功的一种新的免疫增强剂———白细胞介素-2(IL-2),它是由多个氨基酸组成的糖蛋白。IL-2具有促进体液免疫和细胞免疫的双重功能,其主要生物学活性有以下几个方面:1直接作用于B细胞促进其增殖、活化、产生抗体。2能显著促进T细胞活化、增殖,并增加杀伤性T细胞的作用。3刺激自然杀伤细胞,并增强其溶细胞活性。4可诱导杀伤性T细胞、淋巴因子激活的杀伤细胞等杀伤细胞的分化和效应,并诱导这些杀伤细胞产生干扰素、肿瘤坏死因子等细胞因子。5能活化巨噬细胞,增加吞噬病原体功能。大量试验证…  相似文献   

2.
禽类免疫系统的结构与功能   总被引:1,自引:0,他引:1  
禽类免疫系统知识大多来自对鸡的研究,鸡和哺乳动物的免疫机制存在许多相似之处,但两者也存在重要的差异性,信类受到抗原刺激产生抗体和细胞免疫应答,主要有三类抗体:IgM,IgG(亦称IgY(),和IAgA,通过基因转换获得抗体多性,T淋巴细胞是细胞免疫的主要效应细胞,禽类T细胞有两种不同的分化途径即α/β,γ/β,类似于哺乳动物T细胞受体机制,通过结合和连接机制产生禽类T细胞多样性,同哺乳动物T细胞一样,禽类T细胞参与MHC限制的辅助细胞和细胞毒性细胞功能,天然效应细胞由自然杀伤细胞(NK细胞)和抗体依赖细胞的细胞毒性作用(ADCC)介导,近年禽类一些细胞因子得到克隆和表达,许多病毒引起鸡免疫抑制,目前我们感兴趣的是如何了解免疫抑制的机制以及采取何种策略增强商业鸡群的免疫应答能力。  相似文献   

3.
<正>1976年,D.A.Morgan等[1]最先报道,用丝裂原刺激鼠脾淋巴细胞可产生白细胞介素-2(IL-2)。IL-2具有激活杀伤细胞和自然杀伤细胞,刺激T淋巴细胞和自然杀伤细胞产生细胞因子的能力,在机体的免疫应答中起重要作用。IL-2作为新型免疫佐剂,不同于以前的化学佐剂,它不仅能避免常规佐剂的不良反应,而且能增强病毒、细菌和寄生虫疫苗的免疫效果,在改变免疫应答强度的同时改变免疫应答  相似文献   

4.
鸡白细胞介素-2(IL-2)是由激活的T细胞分泌产生的糖蛋白,具有显著的免疫增强作用,不仅在T细胞、B细胞的生长与分化和NK细胞的激活等方面发挥重要作用,而且与其他细胞因子一起发挥免疫功能,是一种能影响机体免疫反应各个方面的调节因子。文章综述了鸡白细胞介素-2分子生物学和疾病防治应用研究进展。  相似文献   

5.
《北方牧业》2012,(18):28
正1主要成分银花、连翘、柴胡、大青叶、金丝桃素、聚肌胞等。本品为淡黄色粉末2药理作用清热解毒、益气健脾。刺激机体产生T淋巴细胞和B淋巴细胞,增强淋巴细胞的繁殖,激活抗原,促使其分化增殖,产生效应细胞、行使其免疫功能。加快自然杀伤细胞的繁殖,自然杀伤细胞具有白介素-2中亲和性受体,在白介素-2刺激下可发生增  相似文献   

6.
雏鸡1日龄感染鸡贫血病毒,8日龄接种Lasota疫苗,以未感染免疫雏鸡为对照,于免疫后7、14、28d检测血清免疫球蛋白IgG、IgM、IgA,在凝抑制抗体(HI)滴度;胸腺、法氏囊、脾脏T细胞、IgG^ 、IgM^ 、IgA^ ,抗体生成细胞数量及T、B细胞增殖反应;胸腺、脾脏细胞因子IL-2、IFN活性的变化。结果发现,感染CAV雏鸡Lasota疫苗免疫后,其血清IgG、IgM、IgA免疫球蛋白含量明显减少,HI抗体滴度降低;胸腺、法氏囊、脾脏T细胞、抗体生成细胞数量降低及T、B细胞增殖反应减弱,胸腺、脾脏IL-2及TNF诱生活性降低,表明其细胞免疫和体流免疫功能以及细胞因子免疫调节作用均未感染免疫雏鸡明显减弱。  相似文献   

7.
超抗原为一类特殊的抗原分子,对机体的免疫系统可产生重要的影响,与许多疾病有着极其密切的关系。按其作用的细胞种类,可分为T细胞超抗原(T-SAg)及B细胞超抗原(B-SAg)。T-SAg具极高的T细胞激活频率,反复刺激还可诱导免疫耐受。B-SAg能刺激B细胞产生大量免疫蛋白,激活体液免疫反应和补体级联反应并可特异性诱导B细胞凋亡。据超抗原的作用机制研制超抗原疫苗,将对由于超抗原引起的疾病的防制提供一种新的思路。  相似文献   

8.
白细胞介素-2对犬瘟热疫苗免疫效果的影响   总被引:1,自引:0,他引:1  
白细胞介素-2(interleukin-2,IL-2)是由激活的T淋巴细胞产生的具有广泛生物活性的细胞因子,能激活T淋巴细胞,增强CTL的细胞毒活性,刺激细胞分泌IFN-γ等细胞因子,促进机体的细胞免疫反应;同时也能激活B淋巴细胞,参与机体的体液免疫反应.  相似文献   

9.
白细胞介素18(IL-18)是一种能诱导IFN-γ产生的新型细胞因子。它具有多种生物学功能.能诱导Th1细胞和自然杀伤细胞产生干扰素γ,促进T淋巴细胞和自然杀伤细胞表达FasL,有较强的抗肿瘤和抗微生物感染的作用。  相似文献   

10.
细胞因子与兽医临诊   总被引:3,自引:1,他引:2  
细胞因子(Cytokine)是由免疫活性细胞及其他各种细胞产生的生理活性物质的总称。细胞之间除直接接触发生相互作用外,还能产生细胞因子,并迅速与相邻、局部细胞发生相互作用。因此人们认为细胞因子是细胞的“语言”。过去将由淋巴细胞来源的称作淋巴因子(Lyphokine),将单核细胞、巨噬细胞来源的称作单孩因子(Monokine)。然而,譬如IL-6既可以由T细胞,又能由巨噬细胞、纤维母细胞等多类细胞产生,故接产生细胞则难以进行分类命名。因此,最近人们倾向统称之为细胞因子。细胞因子作为细胞间的信息递质,在免疫反应及感染应答、造…  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
16.
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.  相似文献   

17.
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  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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