应用ELISA检测猪瘟免疫抗体及免疫效果分析

用ELISA检测了接种猪瘟疫苗后的猪血样697份,检测血清抗体阳性637份,阳性率为91.39%.同时对851份血清进行了自然强毒血清抗体的检测,检出阳性76份,阳性率为8.93%.表明青海省猪瘟疫苗注射密度较高,同时反映出在青海省猪群中存在猪瘟自然强毒感染.     

猪瘟强毒单克隆抗体酶联免疫吸附试验对猪瘟血清抗体的检测

应用猪瘟强毒单克隆抗体酶联免疫吸附试验（ELISA）对青海省4个县的免疫猪场629份猪血样进行检测。结果，检出抗体阳性42份，平均阳性率为6.68%。提示经猪瘟疫苗免疫猪群感染了猪瘟强毒。     

蓝耳疫苗对猪群猪瘟抗体水平影响分析

应用酶联免疫吸附试验（ELISA）检测了12个猪场317份血清中的猪瘟和蓝耳抗体,其中免疫蓝耳疫苗的猪群猪瘟和蓝耳抗体阳性率分别为34．64％和90．2％,未免蓝耳疫苗的猪群猪瘟和蓝耳抗体阳性率分别为31．37％和74．39％,结果表明猪群蓝耳病毒的隐性感染和持续感染仍很严重。进一步对免疫和未曾免疫蓝耳疫苗的猪群进行猪瘟和蓝耳抗体阳性率比较,结果发现育肥猪和仔猪的猪瘟和蓝耳病抗体阳性率存在着反比关系,因此,蓝耳疫苗（活苗）的免疫对猪瘟抗体的产生有一定的抑制作用。     

某猪场猪瘟强毒、弱毒抗体水平的检测

应用猪瘟单克隆抗体纯化酶联免疫吸附试验方法，对河南某猪场47份母猪血清进行猪瘟抗体检测，有5份血清呈猪瘟强毒抗体阳性，阳性率为10.6%，猪瘟弱毒抗体阳性率为95.7%，其群体保护率为93％。在9份仔猪血清中，猪瘟强毒抗体为阴性，猪瘟弱毒抗体阳性率为22％，只有17％的群体保护率。检测结果表明：该猪场可能有猪瘟强毒感染。     

2003年我省部分规模化猪场主要猪病免疫监测及其评价

2003年1～12月对全省各地200多个规模化猪场，合计3894份血清，分别进行了猪瘟、口蹄疫、伪狂犬病以及猪兰耳病等几种猪主要传染病的抗体检测。其中，在我们检测的1429份血清中，猪瘟抗体阳性有831份，阳性率为58．2％。检测的332份血清中，口蹄疫抗体阳性159份，阳性率47．9％，检测血清1232份，猪伪狂犬病全毒抗体阳性827份，阳性率67．1％：检测血清901份，其中已免生猪血清594份，兰耳病抗体阳性348份，阳性率58．6％，未免生猪血清307份，抗体阳性133份，阳性率43．3％。     

猪瘟单克隆抗体酶联检测结果分析

采用猪瘟单抗酶联试剂对曾发生过猪瘟的猪群进行了检测。结果表明：猪群的猪瘟弱毒体阳性率为７８．５％，仍有２１．５％的猪免疫不确实、猪群的猪温强毒抗体阳性率为２７．５％，说明猪群感染过猪瘟强毒。猪瘟强毒抗体阳性与猪瘟弱毒抗体，繁殖母猪的胎次无关，与毒猪的繁殖异常有关。     

规模化猪场猪瘟病原与抗体检测分析

为了解规模化猪场猪瘟野毒感染情况和猪瘟疫苗免疫效果,分别采用RT-PCR和ELISA方法对某场72份猪扁桃体样和419份血样进行了猪瘟病原和抗体检测。结果表明,该场无猪瘟野毒感染;种猪群猪瘟抗体阳性率高于90.3%、离散度低于33.1%,猪瘟疫苗免疫效果理想;保育猪猪瘟抗体阳性率仅为79.3%,离散度达到50.4%,抗体水平参差不齐,需采取综合防控措施进一步提高猪瘟抗体水平;母猪猪瘟抗体阳性率随着胎次的增加而呈递减趋势。     

猪瘟疫苗免疫猪群中抗体水平的检测

应用ＰＰＡ－ＥＬＩＳＡ技术对猪瘟疫苗免疫猪群中的血清抗体水平进行了检测。共检测４个县的猪血样４８６份，检出血清抗体阳性４４９份，阳性率为９２．３９％，群体免疫保护率在８４．２４％～９４．２５％之间，群体均分值在８９．５～９８之间。     

猪瘟感染和免疫状况的血清学调查

从宁波市11个县（市）的17个集约化猪场随机采集猪血分离血清，共3437份．其中母猪878份，育肥猪1017份，生长猪778份，哺乳仔猪764份。受检猪均进行过猪瘟疫苗免疫。检验使用猪瘟弱毒或强毒单抗纯化的酶联抗原建立的间接ELISA诊断试剂盒，所用的纯化抗原，阴、阳性标准血清和相关试剂均购自中国兽药监察所。检测结果，猪瘟强毒（野毒）感染率平均14．1％，其中哺乳仔猪（45日龄内）为9．82％。     

种猪场猪瘟病原和抗体检测与分析

为了解某规模化种猪场猪瘟野毒感染情况和猪瘟抗体免疫状况,研究分别采用RTPCR、基因测序和阻断ELISA方法对该场36份猪扁桃体样品和102份血样进行了猪瘟病原和猪瘟抗体检测。结果表明:群体猪瘟野毒阳性率为8.3%,其毒株基因型属于2.1c亚型;种母猪群猪瘟抗体阳性率91.7%、离散度23%,猪瘟免疫效果理想;仔猪猪瘟抗体阳性率80%、离散度46%,猪瘟抗体水平较高但参差不齐。该场通过淘汰野毒感染猪、抗体阴性猪群补打疫苗等综合措施实施猪瘟净化,节本增效,净化取得初步成效。     

Inhibition of African swine fever infection in the presence of immune sera in vivo and in vitro

In assay cultures, sera from African swine fever convalescent pigs inhibited infection by homologous African swine fever virus. The infection-inhibition capacity did not correspond with the virus-neutralizing capacity. The serum did not prevent infection by heterologous virulent viruses. Sera from pigs challenge inoculated with the homologous virulent virus and later with a heterologous virulent virus inhibited the infection by different heterologous virulent viruses. These sera did not interfere with the infection by pseudorabies virus. The specificity of the reaction indicated that the infection inhibition was caused by antibody.     

规模猪场种猪猪瘟群体免疫合格率与抗体离散度监测及免疫效果分析

采用阻断ELISA方法检测广西5个不同规模猪场种猪血清抗体,评价种猪群猪瘟免疫状况.结果显示,5个猪场种猪猪瘟抗体合格率为83.95％(2 045/2 436),抗体离散度为34.41％.将5个猪场按种猪存栏数进行划分,统计结果显示,农村小规模猪场(1 20＜存栏数＜300)猪瘟抗体合格率为81.44％(373/458),抗体离散度为38.28％;大型规模猪场(存栏数＞600)抗体合格率为84.53％(1 672/1 978),抗体离散度为33.33％.由此可见,此次调查猪场种猪猪瘟免疫抗体水平不理想,群体免疫合格率偏低,抗体离散度偏高,大型规模猪场的情况要稍好于农村小规模猪场.     

牛病毒性腹泻病毒感染对猪瘟免疫的影响

猪瘟病毒（CSFV）与同属的牛病毒性腹泻病病毒（BVDV）同源性较高,抗原性上有交叉。本次调查对368份猪瘟免疫猪血清样本进行BVDV抗原检测,其中7份呈阳性,阳性率1.90%。对7份BVDV阳性血清采用ELISA和IHA两种方法检测猪瘟（CSFV）抗体水平,抗体合格率偏低,两者的结果符合率为71%。研究表明：BVDV在一定程度上干扰了猪瘟疫苗的免疫效果,影响抗体水平。     

猪瘟野毒感染抗体阻断ELISA检测方法的建立与初步评价

以猪瘟野毒E2蛋白为包被抗原、辣根过氧化物酶标记的猪瘟野毒单抗作为酶标抗体,建立检测猪瘟野毒抗体的阻断ELISA方法.猪瘟野毒E2最适包被浓度为0.03 μg/mL,待检血清最适稀释度为1∶4,酶标猪瘟野毒单抗稀释度为1∶1 000.用建立的阻断ELISA方法检测369份临床阴性血清,计算阻断率,确定临界值,阻断率＞4...     

Experimental production of congenital persistent swine fever infections: II. Effect on functions of the immune system

Twelve pregnant sows were infected at various stages of gestation with a low-virulent field strain of swine fever (SF) virus. The sows developed neutralizing antibody in serum, colostrum and milk.Only one pig had antibody to SF virus at birth. Twenty-three congenitally infected pigs developed a persistent viraemia. In the plasma samples of these pigs, neither antibodies nor virus-antibody complexes were detected after the disappearance of maternal antibodies.The persistently infected pigs showed a normal antibody response against sheep red blood cells, except in the terminal stage of disease. These observations indicate immunological tolerance to SF virus in these pigs. Immunological tolerance was also induced in pigs which had been infected in utero after the onset of immune competence.The lymphocyte response to phytohaemagglutinin seemed to be slightly depressed in the persistently infected pigs, whereas the response to pokeweed mitogen was comparable with that of control pigs.A clear, cell-mediated immune response to SF virus could not be demonstrated by the lymphocyte stimulation test.Three pigs that were born uninfected did not produce neutralizing antibody following natural exposure from in-contacts, whereas the littermates did. These pigs appeared to be sensitized when challenged with virulent SF virus.     

重组白细胞介素-2提高PRRS抗体阳性猪的猪瘟疫苗免疫效果试验

观察了重组白细胞介素-2（IL-2）对健康成年猪和PRRS抗体阳性猪的猪瘟疫苗免疫效果的影响。结果显示,重组IL-2和猪瘟疫苗一起免疫健康猪,20d后间接血凝抗体滴度达到1∶64的猪的比例为87.5％,而不注射IL-2的对照组抗体滴度可以达到这一水平的比例只有25％。给经2次猪瘟疫苗免疫但抗体滴度在1∶32以下的PRRS抗体阳性猪单独注射IL-2,20d后,注射前检测不到抗体的猪都检测到了抗体,注射前抗体滴度在1∶8～1∶16之间的猪的抗体滴度提高到1∶32～1∶64。再次用猪瘟疫苗和IL-2共同免疫,可使抗体滴度提高4倍以上。而不注射的对照组抗体滴度则略有下降。说明重组IL-2可以减轻PRRS感染所引起的免疫抑制,提高猪瘟疫苗的免疫效果。     

Pestivirus infections in Norway. Serological investigations in cattle, sheep and pigs.

Serum samples from 1,133 dairy cows (187 herds), 3,712 ewes (103 flocks) and 1,317 adult pigs (877 herds), were tested for neutralizing antibodies against the NADL strain of bovine virus diarrhoea virus. The prevalence rate of seropositive animals was 18.5% in cattle, 4.5% in sheep and 2.2% in pigs, such seroreactors being found in 28% of the cattle herds and 18% of the sheep flocks. In all three species the rate showed considerable herd and geographical variation. In cattle the seroreactor rate was similar in herds with normal reproduction and in 62 herds with problems of repeat breeding. Of 31 pig sera containing antibodies against the NADL strain, 27 were also positive in a neutralization test for antibodies against swine fever virus (Baker strain). However, all sera showed a higher titre of antibodies against the bovine strain than against the swine fever virus. It was concluded that the immune response of the pigs had been induced by ruminant pestivirus, and not by swine fever virus.     

Efficacy of a live attenuated vaccine in classical swine fever virus postnatally persistently infected pigs

Classical swine fever (CSF) causes major losses in pig farming, with various degrees of disease severity. Efficient live attenuated vaccines against classical swine fever virus (CSFV) are used routinely in endemic countries. However, despite intensive vaccination programs in these areas for more than 20 years, CSF has not been eradicated. Molecular epidemiology studies in these regions suggests that the virus circulating in the field has evolved under the positive selection pressure exerted by the immune response to the vaccine, leading to new attenuated viral variants. Recent work by our group demonstrated that a high proportion of persistently infected piglets can be generated by early postnatal infection with low and moderately virulent CSFV strains. Here, we studied the immune response to a hog cholera lapinised virus vaccine (HCLV), C-strain, in six-week-old persistently infected pigs following post-natal infection. CSFV-negative pigs were vaccinated as controls. The humoral and interferon gamma responses as well as the CSFV RNA loads were monitored for 21 days post-vaccination. No vaccine viral RNA was detected in the serum samples and tonsils from CSFV postnatally persistently infected pigs for 21 days post-vaccination. Furthermore, no E2-specific antibody response or neutralising antibody titres were shown in CSFV persistently infected vaccinated animals. Likewise, no of IFN-gamma producing cell response against CSFV or PHA was observed. To our knowledge, this is the first report demonstrating the absence of a response to vaccination in CSFV persistently infected pigs.     

河南省部分猪群主要疫病疫苗免疫抗体水平监测与效果分析

2009年1月—2011年12月,从河南省信阳和驻马店地区62个猪场共收集免疫过猪瘟病毒(CSFV)、伪狂犬病毒(PRV)、猪繁殖与呼吸综合征病毒(PRRSV)和猪圆环病毒2型(PCV2)疫苗的猪血液,利用ELISA方法对样品进行抗体水平的检测。结果显示:该地区猪场猪群的疫苗免疫合格率最高是PRV疫苗(87.06%);其次是CSFV疫苗(76.24%);PRRSV和PCV2的疫苗免疫合格率较低,分别为65.20%和50.78%。4种疫苗免疫抗体合格率在不同规模的猪场有较大的差别,规模猪场的猪群某些疫病的抗体未必比散养猪群高。种猪群的4种疫苗的免疫合格率最高,商品猪中各个生长阶段的免疫后抗体合格率比较后发现,断奶仔猪群PRRSV抗体合格率明显高于哺乳仔猪,育肥猪群合格率要比哺乳仔猪群和断奶仔猪群的抗体合格率低。     

The protective value of vaccine-induced neutralising antibody titres in swine fever

The relationship between vaccine-induced antibody titres against swine fever virus (SFV), as measured by the neutralisation peroxidase-linked assay (NPLA), and protection against virus multiplication, excretion and transmission, disease and death was studied in 46 pigs. The pigs were housed individually and challenged intranasally with 100 pig ID50 of the virulent Brescia strain of SFV. In order to detect virus transmission, a swine fever (SF)-susceptible sentinel pig was placed in contact with the vaccinated animal 2 days after challenge. All 11 pigs with pre-challenge NPLA titres less than 12.5 responded to the challenge with fever, 8 out of 10 showed leucopenia, 7 transmitted virus to their contact and 3 died. Of the 9 animals with titres greater than or equal to 12.5 and less than 25, 8 developed fever, 6 out of 7 had leucopenia, 2 excreted and/or transmitted virus and all survived. Of the 12 pigs with pre-challenge titres greater than or equal to 25 and less than 50, 5 responded with fever, 6 out of 10 had leucopenia, 4 excreted virus and none died. Although all pigs with prechallenge titres greater than or equal to 50 showed a booster response, virus transmission was not observed, indicating that in the case of exposure such animals would not contribute towards the spread of field virus. From an epidemiological point of view, titres less than 32 were found inadequate.