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1.
Ovine enzootic abortion (OEA) is caused by Chlamydophila abortus, an intracellular bacterium which acts by infecting the placenta, causing abortion in the last term of gestation. The main prevention strategy against OEA is the vaccination of flocks. An effective vaccine against C. abortus must induce a Th1-like specific immune response, which is characterized by the early production of IFN-gamma and the activation of CD8(+)T cells. Moreover, vaccine effectiveness could be modulated by the functioning of the innate immunity. The purpose of this study was to ascertain how polymorphonuclear neutrophils (PMNs) and NK cells might influence vaccine-induced protection. The live attenuated 1B vaccine and two inactivated experimental vaccines, adjuvated with aluminium hydroxide (AH) or QS-21 (QS), were used in PMN-depleted or NK cell-depleted mice. For PMN depletion, RB6-8C5 monoclonal antibody, which recognizes GR1(+) receptors (Robben, P.M., LaRegina, M., Kuziel, W.A., Sibley, L.D. 2005. Recruitment of Gr-1(+) monocytes is essential for control of acute toxoplasmosis. The Journal of Experimental Medicine 201, 1761-1769.) was used, while for NK cell-depletion the anti-asialo GM1 polyclonal antibody was used. The depletion of PMNs caused 100% mortality in non-vaccinated mice (NV) and 60% mortality in the AH-vaccinated mice by day 10 p.i., while both groups showed a significant increase in their bacterial burden in the liver by day 4 p.i. The depletion of NK cells caused mortality only in the NV group (50% by day 10 p.i.), although this group and the 1B vaccinated mice showed an increased bacterial burden in the liver at day 4 p.i. Our results suggest that the importance of PMNs in inactivated vaccines depends on the adjuvant chosen. The results also demonstrated that the importance of NK cells is greater in live vaccines than in inactivated vaccines.  相似文献   

2.
Mouse models have been widely used to test candidate vaccines against Chlamydophila abortus infection in mice. Although the induction of a systemic infection by endogenous or intraperitoneal inoculation is a useful tool for understanding the immune mechanism involved in the protection conferred by the vaccination, a different approach is necessary to understand other factors of the infection, such as mucosal immunity or the colonization of target organs. To test whether C. abortus intranasal model of infection in mice is a useful tool for testing vaccines in a first group of experiments mice, were infected intranasally with C. abortus to characterize the model of infection. When this model was used to test vaccines, two inactivated experimental vaccines, one of them adjuvated with QS-21 and another with aluminium hydroxide, and a live attenuated vaccine (strain 1B) were used. Non-vaccinated control mice died within the first 8 days, after displaying substantial loss of weight. Histologically, the mice showed lobar fibrinopurulent bronchointerstitial pneumonia. Prior immunization with QS-21 adjuvated vaccine or 1B vaccine presented mortality and the recipients showed a greater number of T cells in the lesions, especially CD8(+) T cells, than the control mice and mice immunized with vaccine adjuvated with aluminium hydroxide. The results confirm that the C. abortus intranasal model of infection in mice is a useful tool for testing vaccines.  相似文献   

3.
Intradermal vaccination with plasmid DNA encoding envelope glycoprotein C (gC) of pseudorabies virus (PrV) conferred protection of pigs against Aujeszky's disease when challenged with strain 75V19, but proved to be inadequate for protection against the highly virulent strain NIA-3. To improve the performance of the DNA vaccine, animals were vaccinated intradermally with a combination of plasmids expressing PrV glycoproteins gB, gC, gD, or gE under control of the major immediate-early promotor/enhancer of human cytomegalovirus. 12.5 microg per plasmid were used per immunization of 5-week old piglets which were injected three times at biweekly intervals. Five out of six animals survived a lethal challenge with strain NIA-3 without exhibiting central nervous signs, whereas all the control animals succumbed to the disease. This result shows the increased protection afforded by administration of the plasmid mixture over vaccination with a gC expressing plasmid alone. A comparative trial was performed using commercially available inactivated and modified-live vaccines and a mixture of plasmids expressing gB, gC, and gD. gE was omitted to conform with current eradication strategies based on gE-deleted vaccines. All six animals vaccinated with the live vaccine survived the lethal NIA-3 challenge without showing severe clinical signs. In contrast, five of six animals immunized with the inactivated vaccine died, as did two non-vaccinated controls. In this test, three of six animals vaccinated with the DNA vaccine survived without severe clinical signs, whereas three succumbed to the disease. Comparing weight reduction and virus excretion, the DNA vaccine also ranged between the inactivated and modified-live vaccines. Thus, administration of DNA constructs expressing different PrV glycoproteins was superior to an adjuvanted inactivated vaccine but less effective than an attenuated live vaccine in protection of pigs against PrV infection. Our data suggest a potential use of DNA vaccination in circumstances which do not allow administration of live attenuated vaccines.  相似文献   

4.
Chlamydophila abortus is the causative agent of abortion in pigs and pregnant women. Seroconversion rates were arranged from 11% to 80% in piglets and sows in China. These very high rates illustrate the scale of the problem in China and highlight the urgent need for the development of a C. abortus vaccine. An efficacious anti-chlamydial vaccine should induce not only strong mucosal and systemic T-helper type 1 (Th1) immune response but also give a humoral response that enhances Th1 activation following infection. In order to evaluate an active immune response of a combination of the major outer membrane protein (MOMP) DNA- and protein-based vaccines, 54 BALB/c mice were randomly assigned to six groups and inoculated intramuscularly with: (i) 100 microg pcDNA::MOMP, (ii) 10 microg r-MOMP, (iii) primed with 100 microg pcDNA::MOMP and boosted with 10 microg r-MOMP, (iv) primed-boosted with a combination of pcDNA::MOMP and r-MOMP simultaneously, (v) live-attenuated 1B vaccine, (vi) 100 microg pcDNA3.1 vector. All animals were vaccinated two times at 14 days intervals. Results showed that mice given DNA and r-MOMP induced higher antibody levels, higher T cells proliferation and an elevated level of chlamydial clearance in spleen, which was equivalent to the clearance of 1B vaccine. Mice administrated the DNA-primed/MOMP-boosted approach elicited moderate antibody levels, less T-lymphocyte proliferation and lower chlamydial clearance as compared with 1B vaccine. Co-immunization with DNA- and r-MOMP vaccine may provide novel ways for active immunization strategy against swine C. abortus.  相似文献   

5.
非洲猪瘟(African swine fever,ASF)给全球养殖业造成了巨大的威胁和挑战.非洲猪瘟病毒(African swine fever virus,ASFV)具有比寻常病毒更加巨大的基因组、迅速的变异能力和更加复杂多变的免疫逃逸机制,目前市场上仍无有效预防疫苗.科研人员几十年来,从灭活疫苗、减毒活疫苗、亚单...  相似文献   

6.
Vaccination is the best approach for controlling the spread of chlamydial infections, in animal and human populations. This review summarises the progress that has been made towards the development of effective vaccines over the last 50 years, and discusses current vaccine strategies. The ultimate goal of vaccine research is to develop efficacious vaccines that induce sterile, long-lasting, heterotypic protective immune responses. To date, the greatest success has been in developing whole organism based killed or live attenuated vaccines against the animal pathogens Chlamydophila abortus and Chlamydophila felis. However, similar approaches have proved unsuccessful in combating human chlamydial infections. More recently, emphasis has been placed on the development of subunit or multicomponent vaccines, as cheaper, safer and more stable alternatives. Central to this is a need to identify candidate vaccine antigens, which is being aided by the sequencing of representative genomes of all of the chlamydial species. In addition, it is necessary to identify suitable adjuvants and develop methods for antigen delivery that are capable of eliciting mucosal and systemic cellular and humoral immune responses. DNA vaccination in particular holds much promise, particularly in terms of safety and stability, although it has so far been less effective in humans and large animals than in mice. Thus, much research still needs to be done to improve the delivery of plasmid DNA, as well as the expression and presentation of antigens to ensure that effective immune responses are induced.  相似文献   

7.
为了构建口蹄疫与伪狂犬病二价基因工程疫苗株 ,将口蹄疫病毒 (FMDV) P1基因插入到伪狂犬病病毒 (PRV)通用载体 p Pg G- uni中 ,得到 PRV转移载体 p Pg G- P1。将转移载体与 Eco R 线性化后的 PRV弱毒疫苗株 TK- /g G- / lac Z 基因组 DNA共转染 PK- 15细胞 ,转染产物经多次空斑纯化和 PCR鉴定 ,获得了纯化的重组 PRV TK- /g G- / Pg G- P1,重组病毒基因组 DNA经酶切鉴定进一步表明 ,FMDV的 P1基因已成功地整合到 PRV弱毒疫苗株的基因组中。Western blot试验表明 ,FMDV P1基因在重组 PRV中得到表达。该研究为进一步研制口蹄疫与伪狂犬病二价基因工程疫苗奠定了坚实的基础  相似文献   

8.
布鲁氏菌弱毒疫苗粘膜免疫及检测方法的研究   总被引:1,自引:0,他引:1  
为研究布鲁氏菌弱毒疫苗粘膜免疫及其检测方法,本实验采用粘膜点眼途径对健康母羊接种布鲁氏杆菌猪2号疫苗(S2)、牛19号疫苗(A19)和羊强毒株(M16),筛选布鲁氏杆菌病鉴别检测方法。将12月龄~14月龄母羊60只随机分为3组,以常规疫苗推荐剂量进行半量粘膜点眼接种。采集血液、淋巴、脏器进行布鲁氏菌病血清学检测和细菌学分离以及PCR检测。结果表明:布鲁氏菌弱毒疫苗抗体水平持续6个月,其中血清学的试管凝集试验、半胱氨酸凝集试验与补体结合试验的阳性符合率达到100%。细菌分离期为6个月,乳腺、乳腺淋巴、髂淋巴分离率较高;而强毒株M16的抗体水平和细菌分离持续12个月以上。结果显示以常规血清学和细菌学检测方法在点眼免疫布鲁氏菌S2、A19苗6个月后可以进行野毒感染和疫苗免疫畜的鉴别诊断。  相似文献   

9.
Live attenuated vaccines against Chlamydia psittaci var ovis, Brucella melitensis and Salmonella abortus ovis have previously been shown to be compatible in mice by subcutaneous administration. Immunity against challenge with virulent chlamydia was, however, slightly decreased in associations including the B melitensis Rev 1 vaccine. The chlamydia strain 1B vaccine was administered to four- to five-month-old female lambs, either alone or in combination with the B melitensis Rev1 and the S abortus ovis Rv6 vaccines. Clinical, serological and bacteriological observations demonstrated the compatibility of the three vaccines. Control, singly and triply vaccinated ewes were challenged with a virulent strain of chlamydia during their second pregnancy, 15 months after vaccination. Five of the 12 control ewes lambed normally and 10 of them were infected, as shown by the excretion of the challenge chlamydia in genital secretions. Sixteen of the 17 ewes in the triple vaccine group lambed normally and none was infected. All 12 in the single vaccine group lambed normally and three of the 12 were infected. In spite of this unusually poor protection by the single vaccine, antichlamydial immunity was clearly not decreased by the association with the two other vaccines.  相似文献   

10.
Avian influenza (AI) is an acute respiratory disease caused by influenza A virus.Avian influenza virus (AIV) can infect poultry,wild birds and some mammals including human.AI is a big threat to both poultry and human health because the virus can cross the species barrier to get the capacity of transmitting from poultry to human.Vaccination is the most efficient measure against AI outbreaking.Traditional vaccines include inactivated vaccine based on chick embryo and attenuated vaccine.Although the traditional vaccines play important roles in the past AI epidemics,many disadvantages have been proved to exist in traditional vaccines.Forced by major drawbacks of traditional vaccines,several studies focused on the development of novel vaccines.In this review,we reviewed recombinant live vector vaccine,subunit vaccine,DNA vaccine and virus-like particle vaccine of AI in order to provide some references for prevention and control of AI.  相似文献   

11.
禽流感是由A型流感病毒引起的一种急性呼吸道传染病,家禽、野鸟和部分哺乳动物均可感染.禽流感给中国养殖业造成了巨大的损失,同时,随着病毒的种间传播,人类的生命安全也受到了严重威胁.目前,疫苗免疫仍是防控禽流感最主要的手段,传统的疫苗主要有鸡胚灭活苗和禽流感弱毒疫苗.虽然在过往几次禽流感暴发过程中,传统疫苗发挥了重要作用,但其自身却存在诸多弊端,因此研制新型疫苗来弥补传统疫苗的不足是很有必要的.文章主要对禽流感重组活载体疫苗、基因工程亚单位疫苗、DNA疫苗和病毒样颗粒疫苗等新型疫苗的研究进展进行综述,旨在为禽流感的防控提供参考.  相似文献   

12.
寄生虫虫苗的研究概况   总被引:3,自引:0,他引:3  
目前,寄生虫虫苗可以分为5类,即弱毒活苗,排泌物抗原苗,基因工程苗,化学合成苗及基因苗。本文对此5类虫苗的研究现状、制备方法及种类与应用前景作了概述。  相似文献   

13.
A live, attenuated vaccine is currently the only viable option to control of CBPP in Africa. It has been suggested that simple modifications to current vaccines and protocols might improve efficacy in the field. In this report we compared the current vaccine formulation with a buffered preparation that maintains Mycoplasma viability at ambient temperature for a longer time. Groups of animals were vaccinated with the two formulations and compared with non vaccinated groups. Half of the animals in each group were challenged 3 months post vaccination, the other half after 16 months. Protection levels were measured using the pathology index, calculated from post mortem scores of lesions from animals killed during the course of clinical disease. In the challenge at 3 months post vaccination, the protection levels were 52% and 77% for the modified and current vaccine preparations, respectively. At 16 months post vaccination, the protection levels were 56% and 62% for the modified and current vaccine preparations, respectively. These findings indicate that there are no differences in protection levels between the two vaccines. Because of its longer half life after reconstitution, the modified vaccine might be preferred in field situations where the reconstituted vaccine is likely not to be administered immediately.  相似文献   

14.
鼠疫是一种烈性人兽共患传染病,曾经导致历史上10多亿人死亡,目前在世界各地还均有流行。抗生素治疗一般对腺鼠疫有效,但难以治疗肺鼠疫,经常有抗生素治疗仍死亡的情况发生。灭活疫苗对肺鼠疫无效,减毒活疫苗存在毒力返强的安全隐患。F1和V亚单位疫苗在动物模型中对腺鼠疫和肺鼠疫均有效,已经用减毒沙门菌系统通过口服和鼻腔途径传递系统进行免疫研究。文章综述了鼠疫亚单位疫苗和减毒活载体疫苗抗原免疫学研究进展。  相似文献   

15.
动物衣原体病由衣原体感染引起,发病动物通常出现流产、产死胎或产蛋下降等临床症状。该病在牛、羊、猪、鸡、鸭等畜禽,以及狐狸、鹿等特种经济动物间广泛流行,严重妨碍了动物的健康发展。文章对动物衣原体病目前的防控进行了综述,主要包括疫苗免疫和药物治疗两方面,疫苗免疫是目前动物衣原体病预防的最经济有效的方法,而药物治疗是动物感染衣原体的最佳选择。其中重点阐述了灭活疫苗、减毒活疫苗、DNA疫苗、亚单位疫苗、活载体疫苗等多种疫苗的特性及最新研究进展,药物重点介绍了抗生素及中医药的研究进展,探索了其他药物治疗的前景,并对动物衣原体病的未来防控进行了展望。  相似文献   

16.
三个厂家猪瘟活疫苗免疫效果比较试验   总被引:1,自引:0,他引:1  
在同一条件下对3个厂家生产的猪瘟细胞源活疫苗进行了免疫效果评价试验,并与猪瘟传代细胞苗免疫效果进行比较。结果发现3个厂家生产的猪瘟细胞源活疫苗存在一定差异,2个厂家的免疫效果较好,1个厂家的免疫效果较差。猪瘟传代细胞苗免疫效果优于猪瘟细胞源活疫苗,猪瘟传代细胞苗免疫1次,抗体合格率高,持续时间长,猪瘟细胞源活疫苗要免疫两次才能获得比较好的效果。同时,我们发现高致病性猪蓝耳病活疫苗(JXA1-R株)对猪瘟抗体产生有一定影响。  相似文献   

17.
犬瘟热的诊断及其预防免疫的研究进展   总被引:36,自引:7,他引:29  
本文对犬瘟热(CD)的诊断、预防免疫和免疫失败的影响因素及犬瘟热病毒(CDV)的宿主范围进行了综述。CDV不仅感染陆生食肉动物,而且也感染水生食肉动物,并且其宿主范围还在不断扩大。CDV感染主要采用病毒分离、特异性病毒抗原或特异性核酸检测等方法确诊。疫苗包括灭活的CDV疫苗、麻疹病毒(MV)异源苗及CDV弱毒活苗。疫苗接种犬的免疫反应主要取决于毒株特性及犬的应答能力,只有弱毒活苗能诱导产生持久而坚强的保护力。尽管多年来CDV弱毒活苗的使用控制了CD的发生,但最近免疫过的犬发生CD的病例并不少见。分析免疫失败的原因,主要是母源抗体干扰、疫苗质量差、其它病毒的免疫抑制以及CDV流行株可能发生了变异等因素的影响。  相似文献   

18.
Brucellosis is a zoonotic disease threatening the public health and hindering the trade of animals and their products, which has a negative impact on the economic development of a country. Vaccination is the most effective way to control brucellosis. The recombinant vector vaccines are promising candidates for immunization in humans and animals. In this study, the gene encoding OMP19 antigen was primarily amplified and cloned into an expression vector called pT1NX, and then transformed to L. casei cell via electroporation technique. The expression was confirmed using specific antibody against the recombinant protein via immunological screening tests such as western blot and immunofluorescence assay. Finally, recombinant L. casei was orally fed to mice and the results were further recorded, indicating that the mice group which received OMP19 through L. casei based vaccine represented a very good general and mucosal immune responses protective against challenges with virulent B. abortus 544 strain compared with negative control recipient groups. Therefore, the vaccine produced in this research plan can be a very good candidate for protection against brucellosis.  相似文献   

19.
某地区猪繁殖与呼吸综合征病毒(PRRSV)与中国高致病性猪繁殖与呼吸综合征病毒(hp-PRRSV)同源性极高,为了筛选适合该地区病情的疫苗,指导养殖户生产,试验选择hp-PRRS弱毒活疫苗(JXA1-R株)和PRRS弱毒活疫苗(VR-2332株)作为疫苗候选株,选取30日龄、健康状况良好、群体差异性小的断奶仔猪30头,随机分成A、B和C组,每组10头,A组注射hp-PRRS弱毒活疫苗(JXA1-R株),B组注射PRRS弱毒活疫苗(VR-2332株),C组注射相同剂量生理盐水作对照,免疫前和免疫后14、28、42、56、70、84 d采集血清,通过淋巴细胞计数、血清病毒核酸检测、血清抗体检测等分析猪体内hp-PRRS弱毒活疫苗(JXA1-R株)和PRRS弱毒活疫苗(VR-2332株)免疫应答情况.试验结果显示,淋巴细胞数量方面,仔猪免疫后,淋巴细胞数量均上升,42 d时A、B组均达到最大值,A组为19.3×109/L,B组为16.7×109/L,C组则一直处于原始水平;抗体阳性方面,14 d时A组为80%,B组为60%,C组为0,42 d时A组为100%,B组为80%,C组为0;病毒核酸阳性率方面,14 d时A组为90%,B组为100%,C组为0,42 d时,A组为40%,B组为70%,C组为0,70 d时,A组为0,B组为20%,C组为0.由此可知,hp-PRRS弱毒活疫苗(JXA1-R株)能快速诱导猪发生免疫应答、产生免疫抗体,抗体持续时间长、效价高、稳定性良好,且疫苗毒在体内存在时间短、减毒时间快、安全性高,对所研究地区猪群免疫具有优越效果.  相似文献   

20.
Injection of plasmid DNA encoding pseudorabies virus (PRV) glycoproteins into pig muscle has been shown to result in protective immunity against lethal infection. Nevertheless, such DNA vaccines are still less efficient than some attenuated or killed live vaccines. One way to increase DNA vaccine efficacy is to improve the vectorisation system at the molecular level, thereby enhancing the rate of in vivo-produced immunogen protein and consequently specific acquired immunity. The present study compared the effectiveness of the protein expression system depending on Sindbis virus (SIN) replicase [J. Virol. 70 (1996) 508] with that of more classical pcDNA3 plasmid. Pigs were vaccinated twice at 3-week interval with a mixture of three pcDNA3 plasmids expressing gB, gC and gD (designated as PRV-pcDNA3) or a mixture of three SIN plasmids expressing the same glycoproteins (PRV-pSINCP), and were challenged with a highly virulent PRV strain. The two DNA vaccines induced PRV-specific T cell-mediated immune response characterized by very low levels of IFN-gamma mRNA in PBMC after in vitro antigen-specific stimulation. Very low levels of neutralizing antibodies (NAb) were also obtained in sera following DNA injection(s). A second DNA injection did not boost immune responses. After a lethal challenge, high levels of IFN-gamma mRNA and high NAb response were induced in all DNA-vaccinated pigs, regardless of the vector used. Therefore, the two eukaryotic expression systems showed comparable efficacy in inducing antiviral immunity and clinical protection against PRV in pigs. This suggests that SIN DNA-based vector immunizing potential may differ according to antigen and/or host.  相似文献   

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