Association of the time that elapsed from last vaccination with protective effectiveness against foot-and-mouth disease in small ruminants

Routine and emergency vaccination of small ruminants against foot-and-mouth disease (FMD) is mandatory in many endemic countries, yet data on the field effectiveness of the vaccines used is scarce. We conducted an investigation of a serotype O FMD outbreak that took place in a sheep and goat pen, and estimated the effectiveness of various routine vaccination statuses. We also evaluated the protection provided by colostrum administration and emergency vaccination. Animals which were routinely vaccinated twice were not clinically affected while disease incidence was observed among animals routinely vaccinated only once (p = 0.004 according to a two-sided Fisher''s exact test). In groups vaccinated only once, there was a significant association between the average time that elapsed since last vaccination and the disease incidence (n = 5; Spearman correlation coefficient: r_s = 1.0, p < 0.01). In addition, non-vaccinated lambs fed colostrum from dams vaccinated more than 2 months before parturition had a mortality rate of 33%. Administration of emergency vaccination 2 days after the occurrence of the index case was the probable reason for the rapid blocking of the FMD spread within 6 days from its onset in the pen.     

利用转基因植物生产口蹄疫可饲疫苗的研究进展与前景

从口蹄疫可饲疫苗的研究概况、生产技术要点、优缺点及需要改进的问题几方面阐述了利用植物反应器生产口蹄疫可饲疫苗的研究前景。综述了口蹄疫可饲疫苗的研究进展，介绍了利用植物反应器生产口蹄疫可饲疫苗的技术要点，包括在口蹄疫病毒遗传转化质粒载体系统中最常用的农杆菌介导法，提出了生产口蹄疫可饲疫苗需要改进的技术问题。     

以乳酸杆菌为载体的口蹄疫病毒VP1基因DNA疫苗猪体免疫试验

给猪口服和肌肉注射以乳酸杆菌为载体的口蹄疫病毒VP1基因DNA疫苗（L．acido SFMD-1），以正向间接血凝试验（IHA）和MTT方法分别检测了免疫后FMDV VP1抗体的动态变化和特异性T细胞增殖反应情况，并与商用FMD油佐剂疫苗、裸质粒FMDV VP1基因DNA疫苗诱导的特异性免疫抗体水平进行了比较。结果显示，口服组猪在免疫后第21d抗体效价达到了1：2^7.7，而肌肉注射组猪为1：2^3.3。加强免疫后2周，口服免疫组抗体水平下降到1：2^5.3，到第3周快速上升到1：2^8；与此相对应，肌肉途径免疫组猪抗体效价缓慢地从1：2^5.3上升到1：2^6.7。口服途径和肌肉注射途径的刺激指数（SI）分别为1．93和2．00，2种免疫途径都可以诱导特异性T细胞增殖反应。证实，该疫苗能够在猪体诱发VP1特异性T细胞和B细胞反应，以乳酸杆菌为载体是DNA免疫和预防猪口蹄疫的一种极有前景的方法。     

Serological response to a booster foot-and-mouth disease vaccination with strains different from the primary vaccine

Young calves were vaccinated with Belgian foot-and-mouth disease (FMD) vaccine and revaccinated with either the same vaccine or with a foreign FMD vaccine.There was a significant serological response to the primary vaccine strains after the first vaccination which was greater following revaccination. At one and two months after revaccination there was no significant difference between the responses to revaccination with vaccine identical to the primary vaccine or with the foreign FMD vaccine.It was concluded that revaccination of young calves is effective even with an FMD vaccine different from the primary vaccine.     

囊素对猪口蹄疫灭活疫苗的免疫增强作用

用提取的天然囊素（10ug／mL）和O型口蹄疫灭活疫苗协同免疫45日龄仔猪，研究了其对。型口蹄疫灭活疫苗免疫效果及仔猪增重的影响。将32头健康45日龄仔猪随机分为4组，0．5mL疫苗＋囊素免疫2次（Ⅰ）组、1、0mL疫苗＋囊素免疫2次（Ⅱ）组、1．0mL疫苗＋囊素免疫1次（Ⅲ）组和1．0mL疫苗免疫2次（Ⅳ）组（疫苗对照组），用液相阻断酶联免疫吸附试验（LB—ELISA）检测各组猪免疫前及一免后第14、28、42、60、74、88、102d的口蹄疫血清抗体效价并称重。结果。Ⅱ组抗体水平显著高于Ⅳ组（P〈0．01），Ⅰ组、Ⅲ组和Ⅳ组间差异不显著（P〉0．05）；一免后第60～110d仔猪平均日增重囊素组明显高于对照组（P〈0．05）。结果表明，囊素可以提高口蹄疫灭活疫苗的免疫原性，提高猪增重，促进生长发育。     

猪口蹄疫O型合成肽疫苗及其主要特点

口蹄疫是当前严重危害我国养猪业的疾病之一,长期以来免疫接种是我国预防该病的重要措施。近年来研制出的猪口蹄疫O型合成肽疫苗以其免疫原性高、生物安全性好、可有效区分免疫动物和感染动物等优点引起了人们的高度重视。本文主要介绍了口蹄疫病毒、O型口蹄疫病毒的抗原位点和猪口蹄疫O型合成肽疫苗的研究概况及其主要特点,旨在为猪口蹄疫O型合成肽疫苗的推广应用提供参考。     

豚鼠动物模型评价牛口蹄疫Asia-1型灭活疫苗效力的研究

以豚鼠为试验动物模型,探索一种应用豚鼠替代牛进行牛口蹄疫Asia-1型灭活疫苗效力检验的方法.豚鼠和牛同步对6批牛口蹄疫Asia-1型灭活疫苗进行PD50效力检验,其中2批进行重复性试验.豚鼠分别在免疫后7、14、21和28天采血检测Asia-1型的中和抗体水平.统计学分析显示,测定的豚鼠PD50和牛PD50之间具有极...     

武威市肉牛口蹄疫三价苗抗体水平 评估研究

本实验从甘肃省武威市4个县区（凉州区、古浪县、天祝县、民勤县）采集的320份牛血清样品效价进行了检测。中O型抗体检测免疫合格率分别是71.00%,86.30%,80.00%,91.30%,平均合格率为82.15%。检测出亚洲Ⅰ型抗体免疫合格率82.30%,76.30%,70.00%81.30%,平均合格率为77.23%;检测出A型抗体免疫合格率87.75%,93.50%67.30%,76.30%,平均合格率为81.50%。四县区散户肉牛血清样品中O型抗体检测免疫合格率分别：58.80%,61.30%,63.80%,86.30%,平均合格率为67.55%;检测出亚洲Ⅰ型抗体免疫合格率81.00%,75.00%,71.30%,78.80%,平均合格率为76.30%;检测出A型抗体免疫合格率71.00%,77.50%,83.80%,85.00%,平均合格率为79.00%。通过检测结果可以发现武威市肉牛口蹄疫三价苗抗体合格率高于70%,且武威市规模养殖场肉牛口蹄疫三价苗抗体检测合格率高于散养牛的。     

鼠伤寒沙门菌鞭毛蛋白FliC的原核表达及其对口蹄疫疫苗的佐剂作用

用PCR扩增鼠伤寒沙门菌基因FliC,将PCR产物克隆至pMD18-T载体中,构建了克隆质粒pMD18-FliC。克隆质粒和pET-his载体用EcoR/Nhel双酶切,将得到的纯化基因FliC亚克隆至pET-his内,构建重组质粒pET-his-FliC。酶切、测序鉴定后,分别将重组质粒转染大肠杆菌BL21,经IPTG诱导表达,菌体蛋白超声处理,上清液用AKTA Explorer蛋白纯化系统纯化。用SDS-PAGE分析所得蛋白,发现于约53 000处出现了与目的蛋白一致的外源蛋白带。293-mTLR5细胞活性检测表明该融合蛋白能刺激TLR-5通路,引起NF-κB的活化。用小鼠模型检验FliC对O型口蹄疫抗原的免疫增强作用,证明其对口蹄疫疫苗具有佐剂作用。     

Dietary germanium biotite supplementation enhances the induction of antibody responses to foot-and-mouth disease virus vaccine in pigs

We evaluated the potential ability of germanium biotite (GB) to stimulate the production of antibodies specific for foot-and-mouth disease virus (FMDV). To this aim, we measured the total FMDV-specific antibody responses and IgM production after vaccination against FMD both experimentally and in the field. GB supplementation with FMDV vaccination stimulated the production of anti-FMDV antibodies, and effectively increased IFN-γ and TNF-α levels. These results suggest that GB may be a novel alternative feed supplement that can serve as a boosting agent and an immunostimulator for increasing the efficacy of FMDV vaccination in pigs.     

口服6种补益类中药提取物对提高口蹄疫疫苗免疫抗体应答水平的研究

为探究黄芪多糖(APS)、甘草多糖(GPS)、白术多糖(RAMPS)、党参多糖(CPS)、人参根皂甙(GS-R)和人参茎叶皂甙(GSLS)的免疫增强作用,本研究将114只ICR小鼠随机分组进行实验。持续给药2周后免疫注射O型口蹄疫疫苗2次。二免后1~5周每周检测血清抗体。结果表明6种提取物口服均可不同程度提高小鼠口蹄疫抗原特异性Ig G及其亚类(Ig G1、Ig G2a、Ig G2b、Ig G3)的水平。其中口服GSLS(0.5 mg)、APS(25 mg)和GPS(25 mg)小鼠的抗体效价为1∶640、1∶640、1∶320,分别是对照组小鼠抗体效价(1∶80)的8倍和4倍,具有显著性(p0.05)。本研究为GSLS、APS和GPS的增强疫苗免疫效果提供了实验依据。     

抗Asia1型口蹄疫病毒单克隆抗体的制备及生物学特性鉴定

用纯化的Asia1型口蹄疫病毒免疫BALB/c小鼠,取免疫小鼠脾细胞与SP2/0骨髓瘤细胞进行融合,经间接ELISA和间接免疫荧光(IFA)筛选,有限稀释法克隆,获得了2株稳定分泌单克隆抗体的杂交瘤细胞株,分别命名为3H6、5G3,其细胞培养上清效价分别为1:64和1:128,小鼠腹水效价分别为1×10~(-4)和8×10~(-3);ELISA和IFA结果显示,2株单抗仅与Asial型口蹄疫病毒反应,不与O型口蹄疫病毒反应,表明它们均为抗Asial型口蹄疫病毒的型特异性单克隆抗体。westem blot结果显示,2株单克隆抗体均不与全病毒抗原反应,表明它们所针对的抗原表位均为构象表位。相加ELISA试验表明,两株单抗识别不同的抗原表位。经硫氰酸盐洗脱法测定,3H6和5G3的相对亲和力指数分别为1.0 mol/L和1.5 mol/L。这2株单抗的获得为建立口蹄疫病毒检测方法提供了强有力的工具。     

口蹄疫病毒感染与复制多元调控因素研究进展

口蹄疫(foot-and-mouth disease, FMD)是发生于偶蹄动物的一种急性高度传染性疫病,曾多次在世界范围内暴发流行。FMD致病原口蹄疫病毒(foot-and-mouth disease virus, FMDV)于感染后利用多种策略操纵宿主免疫机制和逃避抗病毒反应,以利于其感染复制。现对最近几年来影响调控FMDV感染与复制的多种因素从不同角度进行总结分析,以期为后续研究提供参考。     

口蹄疫病毒整联蛋白受体的研究进展

从组织分布、各毒株利用率、配体结合区介导感染的能力及β亚基胞质区作用等方面论述了4种整联蛋白αvβ1、αvβ3、αvβ6和αvβ8的研究进展，旨在阐明各整联蛋白决定口蹄疫病毒宿主组织嗜性的作用，并为口蹄疫病毒致病机制的研究提供理论依据。     

口蹄疫A型灭活疫苗毒种和种子批的研究

为了保证制苗及攻毒用毒种的质量和稳定性，在对制苗和攻毒毒种的毒力、特异性、保存期、扩繁代次等进行研究的基础上，建立了口蹄疫A型灭活疫苗制苗和攻毒用毒种种子批。结果表明，原始毒种和基础毒种的扩繁代次均控制在5代以内，适宜的保存方法和保存期均为加含500mL／L甘油的PBS后在-30℃保存1年、-70℃保存2年；用于生产抗原的工作毒种，最高扩繁代次控制在15代以内，最佳保存方法和保存期为加保护剂后在-20℃保存半年、-70℃保存1年；用于效力检验的攻毒毒种采用原始毒种。通过制苗和攻毒用毒种种子批的建立，规范了口蹄疫疫苗生产和检验过程中的毒种管理。     

Foot-and-mouth disease: a review of intranasal infection of cattle, sheep and pigs

In an outbreak of foot-and-mouth disease (FMD) it is important to identify animals at risk from airborne virus. Investigations have been carried out over the years to determine the dose required to infect cattle, sheep and pigs by the intranasal route. This paper reviews the results of investigations for animals which have been infected by instillation or spraying a virus suspension into the nostrils or by exposure to affected animals through a mask or by indirect contact. The lowest doses were found by use of a mask. With virus from affected pigs given through a mask, doses of 18 infectious units (IU) in cattle and 8 IU in sheep were found to cause infection and give rise to lesions. Overall, cattle required the least amount of virus followed by sheep. Pigs required a dose of 22 IU to cause infection and a dose of 125 IU to give rise to lesions. In many experiments pigs failed to become infected. With all three species the dose varied with the individual animal and the virus strain. For modelling previous outbreaks and in real time, a dose of 8 IU or 10 and 50% infectious doses (ID50) could be used where cattle and sheep were involved. Experience in the field, combined with the results from experiments involving natural infection, indicate that pigs are not readily infected by the intranasal route. However, for modelling purposes a dose of about 25 IU should be used with care. Investigations are needed to determine doses for virus strains currently in circulation around the world. In addition, the nature of the aerosol droplets needs to be analysed to determine how the respective amounts of infective and non-infective virus particles, host components and, in later emissions, the presence of antibody affect the survival in air and ability to infect the respiratory tract. Further work is also required to correlate laboratory and field findings through incorporation of the doses into modelling the virus concentration downwind in order that those responsible for controlling FMD are provided with the best available assessment of airborne spread. Finally, the doses found for infection by the intranasal route could be applied to other methods of spread where virus is inhaled to assess risk.     

猪口蹄疫病毒多抗原表位的原核表达与纯化

利用限制性酶切从重组质粒pShuttle-CMV-VP中得到猪O型口蹄疫病毒VP1(21-60)-(141-160)-(200-213)位氨基酸的基因。将此多抗原表位基因克隆至原核高效表达载体pET43.1 a(+),在E.coliBL21中用IPTG诱导表达了含有猪口蹄疫病毒多抗原表位的融合蛋白,并用镍柱亲和层析法获得了纯化蛋白。W estern-b lot结果表明融合蛋白可被猪O型口蹄疫病毒标准阳性血清所识别,从而为进一步研究FMDV多表位抗原的免疫特性和诊断方法奠定了基础。     

Parameterization of the duration of infection stages of serotype O foot-and-mouth disease virus: an analytical review and meta-analysis with application to simulation models

Foot-and-mouth disease (FMD) is considered one of the most important infectious diseases of livestock because of the devastating economic consequences that it inflicts in affected regions. The value of critical parameters, such as the duration of the latency or the duration of the infectious periods, which affect the transmission rate of the FMD virus (FMDV), are believed to be influenced by characteristics of the host and the virus. Disease control and surveillance strategies, as well as FMD simulation models, will benefit from improved parameter estimation. The objective of this study was to quantify the distributions of variables associated with the duration of the latency, subclinical, incubation, and infectiousness periods of FMDV transmission. A double independent, systematic review of 19 retrieved publications reporting results from experimental trials, using 295 animals in four reference laboratories, was performed to extract individual values related to FMDV transmission. Probability density functions were fitted to data and a set of regression models were used to identify factors associated with the assessed parameters. Latent, subclinical, incubation, and infectious periods ranged from 3.1 to 4.8, 2 to 2.3, 5.5 to 6.6, and 3.3 to 5.7 days, respectively. Durations were significantly (p < 0.05) associated independently with route of exposure, type of donor, animal species, strains, characteristics of sampling, and clinical signs. These results will contribute to the improvement of disease control and surveillance strategies and stochastic models used to simulate FMD spread and, ultimately, development of cost-effective plans to prevent and control the potential spread of the disease in FMD-free regions of the world.     

Attenuated Salmonella choleraesuis-mediated RNAi targeted to conserved regions against foot-and-mouth disease virus in guinea pigs and swine

In this study, specific sequences within three genes (3D, VP4 and 2B) of the foot-and-mouth disease virus (FMDV) genome were determined to be effective RNAi targets. These sequences are highly conserved among different serotype viruses based on sequence analysis. Small interfering RNA (siRNA)-expressing plasmids (p3D-NT19, p3D-NT56, pVP4-NT19, pVP4-NT65 and p2B-NT25) were constructed to express siRNA targeting 3D, VP4 and 2B, respectively. The antiviral potential of these siRNA for various FMDV isolates was investigated in baby hamster kidney (BHK-21) cells and suckling mice. The results show that these siRNA inhibited virus yield 10- to 300-fold for different FMDV isolates of serotype O and serotype Asia I at 48 h post infection in BHK-21 cells compared to control cells. In suckling mice, p3D-NT56 and p2B-NT25 delayed the death of mice. Twenty percent to 40% of the animals that received a single siRNA dose survived 5 days post infection with serotype O or serotype Asia I. We used an attenuated Salmonella choleraesuis (C500) vaccine strain, to carry the plasmid that expresses siRNA directed against the polymerase gene 3D (p3D-NT56) of FMDV. We used guinea pigs to evaluate the inhibitory effects of recombinant S. cho (p3D-NT56/S. cho) on FMDV infection. The results show that 80% of guinea pigs inoculated with 10⁹ CFU of p3D-NT56/S. cho and challenged 36 h later with 50 ID₅₀ of homologous FMDV were protected. We also measured the antiviral activity of p3D-NT56/S. cho in swine. The results indicate that 100% of the animals treated with 5 × 10⁹ CFU of p3D-NT56/S. cho were protected in 9 days.     

口蹄疫病毒OH株结构蛋白基因VP1的克隆与表达

采用RT—PCR方法扩增获得了O型口蹄疫病毒的主要免疫原VP1基因，将其插入pMDl8-T载体进行序列分析，结果表明，所获得的基因片段含有完整的FMDV结构蛋白VP1编码区。根据表达载体pQE-Trisystem的克隆位点序列和该VPl基因片段的末端序列设计了1对表达引物，以重组pMD-T—VP1阳性质粒为模板，扩增获得了VP1基因，通过酶切将其克隆至表达载体pQE—Trisystem上。经测序证实，重组表达质粒所含的外源基因VP1编码框正确无误。将重组表达质粒pQE—VP1转化至大肠埃希氏菌M15，通过IPTG诱导促使VP1基因高效表达，SDS—PAGE和Western—blot分析表明，表达产物大小与预期的结果（26ku）一致，且具有良好的反应原性。以2mmol／LIPTG诱导表达5h时表达量最高，其中70％～80％的目的蛋白存在于菌体裂解后的上清中，表明外源基因VP1主要以可溶性方式表达。