Porcine interferon-gamma protects swine from foot-and-mouth disease virus (FMDV)

Porcine interferon-gamma (PoIFN-gamma) fused with glutathione S-transferase (GST) was expressed in Escherichia coli BL(21). Twenty 6-week-old piglets were randomly assigned to four groups. Pigs in groups 1-3 were pretreated with 30 mg, 20 mg, and 10 mg recombinant PoIFN-gamma (rPoIFN-gamma), respectively. Pigs in group 4 (control) were pretreated with GST expressed by the empty plasmid. At 48h postinoculation (hpi), all swine were challenged with FMDV (serotype O). Pigs pretreated with 30 mg rPoIFN-gamma were completely protected from virulent FMDV attack. Pigs given 20 mg rPoIFN-gamma achieved partial protection, and the unprotected piglets showed clinical signs from 68h postchallenge (hpc). Although 10 mg rPoIFN-gamma did not confer protection against FMDV, the pigs pretreated with this dose of rPoIFN-gamma presented clinical signs from 35 hpc, which was later than the control group (14 hpc). These results indicate that PoIFN-gamma can protect swine against attack from FMDV or delay the appearance of clinical signs; the effect is dose dependent.     

A serological survey of pigs in Hong Kong for antibodies to Japanese encephalitis virus

Summary A survey of 558 pigs for serological evidence of infection with Japanese encephalitis virus (JEV) performed during the summer of 1968 is recorded. Antibodies were detected by the goose red cell haemagglutination-inhibition test. A high incidence of infection was recorded among mature stock in the New Territories (75·4 per cent) with lower degrees of infection on Hong Kong Island (35·8 per cent) and in Kowloon (26·5 per cent). Of 57 pigs under one year of age only four showed evidence of infection. In view of the widely recorded incidence of JEV in Asia, its occurrence in Hong Kong was to be expected. The regional variation in level of infection within the Colony is probably due to differences in terrain and agricultural development, with consequent differences in availability of mosquito breeding sites. It is concluded that JEV is probably a significant pathogen of pigs and humans in the Colony.

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Resumen Se registra un estudio serológico de 558 cerdos para poner de manifiesto la infección con el virus de encefalitis japonesa (VEJ) llevado a cabo durante el verano de 1968. Fueron descubiertos anticuerpos por medio de la prueba de inhibición de la hemoaglutinación usando glóbulos rojos de ganso. Se registró alta incidencia de la infección entre los cerdos adultos en los Territorios Nuevos (75.4 por ciento) con niveles más bajos en la isla de Hong Kong (35.8 por ciento) y en Kowloon (26.5 por ciento). De 57 cerdos menores de un a?o solamente 4 mostraron evidencia de infección. En vista de la vasta incidencia registrada del VEJ en el Asia, su presencia en Hong Kong era de esperarse. La variación del nivel de infección dentro de la Colonia se debe probablemente a las diferencias en el campo, en el ambiente, y en el desarrollo agrícola con diferencias consecuentes en la disponibilidad de áreas favorables para la crianza del mosquito. Se concluye que el VEJ es probablemente un patógeno de significación para cerdos y humanos en la Colonia.

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Résumé Une enquête sérologique pour mettre en évidence l'infection par le virus de l'encéphalite japonaise a été effectuée sur 558 porcs pendant l'été de 1968. Les anticorps furent recherchés au moyen du test d'inhibition de l'hémagglutination des hématies d'oies. Un très haut taux d'infection fut signalé chez les porcs adultes des New Territories (75, 4 per cent) avec des degrés d'infection plus bas dans l'ile de Hong Kong (35,8 per cent) et dans Kowloon (26,5 per cent). Sur 57 porcs agés de moins d'un an, seulement 4 se révélèrent infectés. Etant donné la très large distribution du virus de l'encéphalite japonaise en Asie, on pouvait s'attendre à le retrouver à Hong Kong. Les différences régionales dans les taux d'infection à l'intérieur de la colonie sont probablement d?es aux différences de terrain et de degré de développement agricole, avec pour conséquence, des différences de possibilités de multiplication des moustiques. On en conclut que le virus de l'encéphalite japonaise est probablement un agent pathogène important pour les hommes et les porcs de la colonie.

     

A serological survey for antibodies to foot-and-mouth disease virus in indigenous Tswana goats and sheep in Kasane, Maun and Shakawe districts in northwestern Botswana

A serological survey was conducted in apparently healthy, unvaccinated indigenous Tswana goats and sheep in Kasane, Maun and Shakawe districts in northwestern Botswana in order to determine in these animals, the levels of exposure to the South African Territories (SAT) serotypes: SAT 1, SAT 2 and SAT 3 of foot-and-mouth disease virus (FMDV). A total of 250, 142 and 134 goat sera originating respectively from Kasane, Maun and Shakawe districts were tested for FMDV antibodies against the three SAT serotypes by the liquid phase blocking enzyme-linked immunosorbent assay and 26 of 250 (10.4%), 5 of 142 (3.5%) and 18 of 134 (13.4%) were positive either to SAT 1 or SAT 3, or to both serotypes. None of the goats' sera was positive to SAT 2 serotype. All sheep sera (n = 9) tested negative against all three serotypes of the virus. The findings are discussed in relation to results of other serological surveys carried out elsewhere.     

A serological survey for infectious bursal disease virus antibodies in free-range village chickens in northern Tanzania

A study of infectious bursal disease (IBD) or 'Gumboro disease' seroprevalence rates in healthy, non-vaccinated indigenous scavenging chickens in northern Tanzania was conducted in November and December 2009 on 362 chickens raised in a traditional management system. Individual bird and flock-level information was collected using a semi-structured questionnaire, and serum samples were screened for IBD virus (IBDV) antibodies using the enzyme-linked immunosorbent assay (ELISA). The study revealed high rates of IBDV antibodies, yielding an overall seropositive rate of 58.8 % and with at least one positive bird detected in 82.8 % (74/90) of flocks. Univariate logistic regression analysis revealed that seropositivity to IBDV varied significantly (chi2 = 16.1, P < 0.001) between the study sites. The flock seroprevalence was found to vary from 37.5 % to 91 % between districts and from 75 % to 90 % between regions. The results of this study showed that IBD is an endemic and widely distributed disease in northern Tanzania.     

O型口蹄疫病毒单克隆抗体的制备及生物学特性分析

以纯化的O型口蹄疫泛亚毒株O/YS/CHA/05抗原免疫BALB/c小鼠,在加强免疫3 d后,取脾细胞与SP2/0骨髓瘤细胞进行融合,经间接ELISA法和间接免疫荧光法(IFA)筛选, 获得2株稳定分泌单克隆抗体的杂交瘤细胞株,命名为4A8和1F6,同时确定二者均为O型口蹄疫病毒特异性单克隆抗体.中和试验和Western-blot分析结果表明,4A8和1F6均识别线性表位,无中和活性.亚类鉴定结果显示:4A8和1F6重链类型分别为IgG1和IgG2b;轻链类型均为κ.相加ELISA分析结果表明,两者针对的抗原位点相同或相近.     

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。     

Reconstitution of immunosuppression mice with mononuclear cells from donors sensitized to foot-and-mouth disease virus (FMDV)

Passive transfer experiments were performed to serve as a basis for analyzing the immune response of adult mice to FMDV infection. Animals were irradiated (750 rad: 1 lethal dose 50%) and reconstituted with allogeneic mononuclear cells from blood, spleen, thymus and peritoneal cavity from donors 2 and 8 days post-inoculation (p.i.). Donors were primed with 10 000 suckling mouse 50% lethal doses of FMDV strain O1 Campos. The following parameters were studied in recipient mice challenged with 10 000 suckling mouse 50% lethal doses of the same virus: (1) viremia; (b) FMDV neutralizing antibody titres; (c) sheep red blood cell (SRBC) hemagglutinating antibody titres. Viremia was substantially prolonged in irradiated control mice, which did not produce detectable antibodies to FMDV or SRBC. In contrast, the span of viremia was markedly shorter in animals reconstituted with cells obtained 8 days p.i. and its eclipse coincided with the onset of neutralizing antibody production. An equally efficient antibody response to the inoculation of SRBC was observed in these animals. No effect was detected after the transfer of cells obtained 2 days p.i. It is concluded that the humoral immune response plays a predominant role in the recovery from FMDV experimental infection in adult mice.     

The minor role of pigs in outbreaks of foot-and-mouth disease of northern Thailand

SUMMARY: A study was undertaken in northern Thailand to examine the involvement of pigs in outbreaks of foot-and-mouth disease (FMD). Data were collected by surveying selected villages, by serological monitoring of pigs and by investigating outbreaks. Fifty-three of 58 villages (91%) surveyed reported that pigs did not develop FMD during the most recent outbreak. The source of 49/60 (82%) outbreaks was attributed to either recent purchases of infected cattle and buffalo or commingling of cattle and buffalo with stock from an infected neighbouring village. One of 60 villages (1.7%) reported that the source was introduced infected pigs. There was no association between the various hypothesised risk factors relating to the management of pigs and the frequency of FMD outbreaks in the survey. The percentage of seropositive pigs during 3 rounds of serological monitoring conducted at 6-monthly intervals in selected villages was 3.5%, 2.6% and 0%, respectively. No clinically affected pigs were observed in 11 outbreak investigations. It was concluded that pigs did not commonly become infected when there were outbreaks of FMD in village cattle and buffalo in northern Thailand. This was probably due to the pig feeding and housing practices employed by villagers that protected pigs from exposure to virus from infected cattle or buffalo, or their products.     

牛口蹄疫病毒VP2结构蛋白抗体间接ELISA方法的建立

为建立牛口蹄疫(FMD)抗体的检测方法,本研究将口蹄疫病毒(FMDV)的VP2基因,通过pPROEXTM HTb表达载体在大肠杆菌DH5α中表达,获得大小为35ku的重组VP2蛋白(rVP2),western blot证实rVP2可与FMDV5种血清型的牛阳性血清发生特异性反应。以纯化复性的rVP2为抗原建立了FMDVrVP2间接ELISA方法。重复性试验证实批内、批间变异系数均小于10%。特异性交叉试验表明,该抗原不与常见的其他7种牛病阳性血清发生交叉反应。检测非免疫无口蹄疫国家牛阴性血清的特异性为100%;检测感染血清敏感性为97.3%;检测O-AsiaⅠ的二价苗免疫牛血清,与4种商品化试剂盒比较,其符合率分别为69.0%、95.0%、90.4%和86.8%。实验结果表明建立的ELISA方法可以用于口蹄疫感染和免疫抗体检测。     

Production and characterization of two serotype independent monoclonal antibodies against foot-and-mouth disease virus

Two foot-and-mouth disease virus (FMDV) monoclonal antibodies (mAbs) were produced from mice immunized with either FMDV serotype A, subunit (12S) or FMDV serotype O, whole virus (140S). Both mAbs (F1412SA and F21140SO) recognized all seven serotypes of FMDV in a double antibody sandwich (DAS) ELISA, suggesting that the binding epitopes of the two mAbs are conserved between serotypes. These mAbs are IgG1 isotype and contain kappa light chains. In order to define the mAb binding epitopes, the reactivity of these mAbs against trypsin-treated and denatured FMDV were examined using an indirect ELISA. The binding site of the mAb, F1412SA is trypsin sensitive and the epitope is linear. Both ELISA and Western blot results suggested that the polypeptide VP2 contributed to the immunodominant site. This mAb showed reactivity to VP2 peptide (DKKTEETTILEDRIL). The mAb, F21140SO, recognized an epitope which is trypsin resistant and discontinuous. This mAb binding to FMDV is dependent on conformational structures of intact viral (140S) or subunit (12S) particle, since it failed to recognize any viral protein in Western blot. This conformational and highly conserved epitope is the first identified epitope among all seven FMDV serotypes. Because the use of mAbs increases the specificity, accuracy and efficiency of diagnostic tests compared to polyclonal antisera, these two mAbs with different specificities are suitable for type-independent diagnosis of FMDV, such as DAS ELISA, or could be adapted to immuno-chromatographic or flow-through rapid test.     

Estimation of 140S particles in foot-and-mouth disease virus (FMDV) vaccine by using the computer analyzing system

The quantity of 140S particles in inactivated foot-and-mouth disease virus (FMDV) vaccine samples produced in Foot-and-Mouth Disease Vaccine Production Center (FMD Vaccine Production Center) in Thailand was estimated by the sucrose gradient ultracentrifugation and optical density analysis by using the computer applying system. The soft ware; Chromato Data System (CDS) (Nihon Chromato Works Co., Ltd. Japan) which is prepared for the analysis of chromatography, was applied for the estimation of 140S particles in FMDV vaccine. The quantity of 140S particles in each vaccine sample measured by CDS was mostly ranged from 2-4 micrograms/ml and this quantity was consistent with the results of the other reports. This method is considered to be the available method for estimation of 140S particles in FMDV vaccine as routine assay.     

Proteomics analysis of porcine serum proteins by LC-MS/MS after foot-and-mouth disease virus (FMDV) infection

To analyze serum proteomics differences between normal and foot and mouth disease virus (FMDV)-infected piglets, an analytical method based on liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used. Samples of venous blood were collected before and after FMDV infection and high abundance serum albumin was removed using a commercial kit. After trypsin digestion, serum samples were processed with LC-MS/MS. Proteins were identified by peptide mass fingerprinting. We found that apolipoprotein A-IV precursor, haptoglobin and probable chemoreceptor glutamine deamidase cheD appeared after FMDV infection in the same piglet. This is believed to be the first time that serum proteomics analysis by LC-MS/MS after FMDV infection has been performed, and our results may provide further information about biomarkers for early diagnosis of FMD in piglets.     

4种ELISA检测奶牛O型口蹄疫免疫抗体的比较试验

口蹄疫(FMD)是由口蹄疫病毒引起的以感染偶蹄动物为主的急性、热性、高度传染性疫病,世界动物卫生组织(OIE)将其列为必须报告的动物疫病.我国规定为一类动物疫病.我国奶牛口蹄疫的防控,以免疫接种措施为核心,实行强制免疫政策,要求O型和Asia Ⅰ型疫苗免疫密度必须达100%,通过牛群整体免疫水平的提高来预防口蹄疫的感染和流行[1].