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1.
The hemagglutinin (HA) gene of A/Swine/Inner Mogolian/547/2001 (H3N2) swine influenza virus (SIV) was recombined into the genome of pseudorabies virus (PRV) Bartha-K61 vaccine strain, generating a recombinant PRV expressing the HA gene, designated as rPRV-HA. One group of 15 mice was inoculated intranasally (i.n.) with 10(5.0) PFU of rPRV-HA, and another two control groups of mice (15 mice per group) were mock-inoculated or inoculated with Bartha-K61. Mice inoculated with rPRV-HA developed hemagglutination inhibition antibodies 3 weeks post-inoculation. Twenty-eight days post-inoculation, all mice were challenged i.n. with 10(5.0) TCID50 of A/Swine/Heilongjiang/74/2000 (H3N2). No challenge virus was isolated from vaccinated mice, and mild pathological lesions were observed only in lungs following challenge. The results demonstrate that the recombinant rPRV-HA expressing the HA gene from H3N2 SIV can protect mice from heterologous virulent challenge, and may represent a candidate vaccine against SIV.  相似文献   

2.
We compared 3 modified-live pseudorabies virus (PRV) vaccine strains, administered by the intranasal (IN) or IM routes to 4- to 6-week-old pigs, to determine the effect of high- and low-challenge doses in these vaccinated pigs. At the time of vaccination, all pigs had passively acquired antibodies to PRV. Four experiments were conducted. Four weeks after vaccination, pigs were challenge-exposed IN with virulent virus strain Iowa S62. In experiments 1 and 2, a high challenge exposure dose (10(5.3) TCID50) was used, whereas in experiments 3 and 4, a lower challenge exposure dose (10(2.8) TCID50) was used. This low dose was believed to better simulate field conditions. After challenge exposure, pigs were evaluated for clinical signs of disease, weight gain, serologic response, and viral shedding. When vaccinated pigs were challenge-exposed with a high dose of PRV, the duration of viral shedding was significantly (P less than 0.05) lower, and body weight gain was greater in vaccinated pigs, compared with nonvaccinated challenge-exposed pigs. Pigs vaccinated IN shed PRV for fewer days than pigs vaccinated IM, but this difference was not significant. When vaccinated pigs were challenge-exposed with a low dose, significantly (P less than 0.05) fewer pigs vaccinated IN (51%) shed PRV, compared with pigs vaccinated IM (77%), or nonvaccinated pigs (94%). Additionally, the duration of viral shedding was significantly (P less than 0.05) shorter in pigs vaccinated IN, compared with pigs vaccinated IM or nonvaccinated pigs. The high challenge exposure dose of PRV may have overwhelmed the local immune response and diminished the advantages of the IN route of vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Evaluation in swine of a subunit vaccine against pseudorabies   总被引：2，自引：0，他引：2  
A subunit vaccine against pseudorabies virus (PRV) was prepared by treating a mixture of pelleted virions and infected cells with the nonionic detergent Nonidet P-40 and emulsifying the extracted proteins incomplete Freund's adjuvant. Three 7-week-old pigs without antibodies against PRV were given 2 IM doses of this vaccine 3 weeks apart. Thirty days after the 2nd vaccination, 10(6) median tissue culture infective doses (TCID50) of a virulent strain of PRV were administered intranasally. Tonsillar and nasal swabs were collected daily between 2 and 10 days after challenge exposure. The pigs vaccinated with the subunit vaccine were not found to shed virulent PRV. Two groups of five 7-week-old pigs vaccinated with commercially available vaccines, either live-modified or inactivated virus, and subsequently exposed to 10(6) TCID50 of virulent PRV, shed virulent virus for up to 8 days. The subunit vaccine induced significantly higher virus-neutralizing antibody titers than either the live-modified or inactivated virus vaccine.  相似文献   

4.
Toxoplasma gondii is one of the most common parasitic pathogens in humans and warm-blooded animals, causing toxoplasmosis. One of the efficient ways to control this disease is immunization. In this study, two recombinant pseudorabies virus (PRV) expressing TgSAG1 (rPRV-SAG1) and TgMIC3 (rPRV-MIC3) based on the PRV vaccine strain were developed by homologous recombination and used for immunizing BALB/c mice. Ninety BALB/c mice were randomly divided into five groups including four experimental groups (inoculated twice in 4 weeks interval with PRV TK-/gG-/EGFP+, rPRV-SAG1, rPRV-MIC3, rPRV-SAG1+rPRV-MIC3, respectively) and one control group (inoculated with medium). All mice vaccinated with rPRV developed a high level of specific antibody responses against T. gondii lysate antigen (TLA), a strong increase of the splenocyte proliferative response, and significant levels of IFN-γ and IL-2 production. These results demonstrated that rPRV could induce significant humoral and cellular Th1 immune responses. Moreover, rPRV immunization induced partial protection against a lethal challenge with T. gondii RH strain, and neutralizing antibodies against PRV in a BALB/c mouse model. The mice immunized with the rPRV-SAG1 and rPRV-MIC3 cocktail could develop higher T. gondii-specific IgG antibodies and lymphocyte proliferative responses and conferred more efficient protection against T. gondii challenge. These results suggested that expression of protective antigens of T. gondii in PRV is a novel approach towards the development of a vaccine against both animal pseudorabies and toxoplasmosis.  相似文献   

5.
In a controlled experiment, 16 wild-trapped raccoons were exposed to 1 of 2 genetically modified live pseudorabies virus (PRV) vaccines used in swine. One vaccine had genes deleted for thymidine kinase (TK(-)) and glycoprotein G (gG(-)); the other had an additional deletion for glycoprotein E (gE(-)). These vaccines were administered orally and intranasally at four dose levels: 10(3), 10(4), 10(5), and 10(6) TCID(50). The 21 days survival rate was 37.5% for the gG(-)TK(-) vaccine; all of the survivors developed antibodies to PRV. All animals receiving the gG(-)gE(-)TK(-) vaccine survived; 75% (all except the lowest dose) developed anti-PRV antibodies. Survivors were challenged intranasally with a 3.2x10(3) TCID(50) dose of the virulent wildtype PRV Shope strain. Two of the remaining three gG(-)TK(-) vaccinated raccoons survived the challenge; for the gG(-)gE(-)TK(-) vaccine, the survival rate was 50% (4/8). The raccoons with higher vaccine-induced antibody titers were more likely to survive the challenge with the virulent PRV; there was a 100% mortality rate for raccoons lacking detectable anti-PRV antibodies. This experiment indicates that exposure of raccoons to modified live gene-deleted PRV vaccines may result in an immune response, and that this immunity provides some protection against exposure to virulent virus.  相似文献   

6.
猪伪狂犬病不同佐剂灭活疫苗对兔免疫原性初探   总被引：1，自引：1，他引：0  
采用分离鉴定的猪伪狂犬病毒（HB—J株）以4种佐剂研制成4批灭活疫苗,以研究其对兔的免疫原性。疫苗分别免疫PRV抗体阴性兔后,用乳胶凝集试验法（LAT）和中和试验法（SNT）对试验兔进行血清抗体检测;于免疫后21、28d对试验兔分别进行攻毒,观察兔保护情况。试验结果表明,兔对不同佐剂的猪伪狂犬病疫苗均产生良好的免疫应答反应,且当兔免疫后血清凝集价≥1：32或血清抗体中和指数≥1479或中和价≥1：16时,可以抵抗10LD50剂量强毒的攻击;当兔免疫后血清凝集价≥1：64或血清抗体中和指数≥2187或中和价≥1：32时,可以抵抗100LD50剂量强毒的攻击;4种佐剂灭活疫苗均具有良好的免疫效果。  相似文献   

7.
A thymidine kinase deficient mutant of the Indiana-Funkhauser strain of pseudorabies virus was tested for its ability to stimulate protective immunity in mice and young pigs. Mice vaccinated intraperitoneally were protected from morbidity and mortality when challenged with 50 LD50 of virulent pseudorabies virus. Eight week old pigs were protected from serious morbidity and mortality when challenged with virulent pseudorabies virus. The thymidine kinase mutant was not shed from the nasal passages of pigs vaccinated intramuscularly, but did not prevent shedding of challenge virus.  相似文献   

8.
Ten inactivated vaccines containing one of four adjuvants and varying concentrations of pseudorabies virus (PRV) antigens were compared in order to select a vaccine suitable for commercial production. A genetically engineered strain of PRV lacking the gene coding for glycoprotein X (gpX) was used in these vaccines. Vaccinated pigs were challenged intranasally with virulent PRV to determine the efficacy of vaccines. Vaccination of pigs with one dose of experimental vaccines adjuvanted with 50% Montanide ISA 50 or 20% Syntrogen induced a protective immunity at least equal to that induced by two commercially available killed PRV vaccines also evaluated. An experimental vaccine containing 20% Syntrogen was selected and further evaluated according to United States Department of Agriculture licensing requirements. None of the pigs vaccinated with this vaccine produced gpX antibodies detectable by the HerdChek: Anti-PRV-gpX assay. Therefore, this assay could differentiate PRV vaccine induced antibodies from antibodies induced by natural exposure when used in conjunction with this killed gpX deleted PRV vaccine.  相似文献   

9.
为探明近年来河南省猪伪狂犬病病毒(PRV)的遗传变异情况,本研究于2017年采集河南漯河和中牟地区疑似伪狂犬病发病养殖场送检的脑组织病料,通过细胞盲传、噬斑纯化、间接免疫荧光试验、Western blotting和透射电镜技术进行病毒分离鉴定。TCID50法测定分离毒株的病毒滴度、生长曲线,通过小鼠感染试验测定分离毒株对小鼠的致死性。对gB、gC和gE基因进行PCR扩增、测序,并与参考毒株序列进行比对分析。结果显示,对PCR鉴定阳性的病料在PK-15细胞盲传后,两份病料在6代内均出现细胞病变,通过间接免疫荧光试验、噬斑纯化和透射电镜技术,成功分离鉴定了两株PRV,分别命名为HeN-LH株及HeN-YM株。分离毒株在PK-15细胞上的生长曲线显示,HeN-LH和HeN-YM株在感染后36 h病毒滴度分别可达108.35和106.63 TCID50/mL。用不同浓度的病毒接种小鼠,结果显示,HeN-LH和HeN-YM株LD50分别为102.13及103.25 TCID50。对gB、gC和gE基因全长扩增测序后构建遗传进化树,结果显示,两株PRV毒株与Bartha、Fa和Ea等经典株的亲缘关系相对较远,而与2011年以来国内不同省份分离的PRV变异株亲缘关系较近。氨基酸序列比对分析显示,与其他变异株相似,gB、gC和gE基因均发生了多个氨基酸的变异,且在特定的位点存在特征性的氨基酸插入和缺失。本研究成功分离鉴定了两株PRV变异株,分离株对小鼠均表现出一定的致病性,本试验结果可为河南省伪狂犬病的防控工作和疫苗株的选择提供科学依据。  相似文献   

10.
A thymidine kinase (TK)-negative (TK-) deletion mutant of the Bucharest (BUK) strain of pseudorabies virus (PRV) was isolated. The mutant, designated as PRV (BUK d13), did not revert to TK-positive (TK+), even when propagated in medium that selected for TK+ viruses. The mutant also replicated equally well at 39.1 C and 34.5 C, and was easily distinguished from other PRV strains by molecular hybridization experiments, restriction nuclease fingerprints, and plaque autoradiography or other assays for the TK phenotype. The PRV (BUK d13) had greatly reduced virulence for mice and rabbits, compared with parental TK+ strains, PRV (BUK-5) and PRV (BUK-5A-R1), and provided mice with solid protection against the TK+ BUK and Aujeszky strains of PRV. Experiments were done in 5- to 6-week-old pigs to assess the safety and efficacy of PRV (BUK d13) in the natural host. In one experiment, pigs were vaccinated IM with 7.5 X 10(8) plaque-forming units of TK- PRV (BUK d13), and were then challenge exposed intranasally (IN) with 4.3 X 10(8) TCID50 of virulent PRV [Indiana-Funkhauser (IND-F)]. Vaccinated pigs did not have clinical signs of illness after vaccination or after challenge exposure. One nonvaccinated control pig died on postchallenge day 4; a 2nd nonvaccinated control pig became moribund, but eventually recovered. Pigs developed virus-neutralizing antibodies after vaccination, and had a secondary immunologic response after challenge exposure; however, PRV was not isolated from the tonsils or trigeminal ganglia of vaccinated pigs at postchallenge exposure day 11.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
《Veterinary microbiology》1997,54(2):113-122
Pseudorabies virus (PRV) vaccines are often compared for their capacity to reduce virus excretion after a challenge infection. Vaccines, used for the eradication of PRV, however, should reduce transmission of PRV among pigs. The purpose of this study was to investigate whether the amount of virus excreted after a challenge infection is an accurate measure of the capacity of a vaccine to reduce transmission of PRV among pigs. Two experiments were carried out, each using two groups of 10 pigs. The pigs in group one were intramuscularly vaccinated once with the glycoprotein E (gE)-negative vaccine X, the pigs in group two with the gE-negative strain 783. Eight weeks later, 5 pigs in each group were inoculated with wild-type PRV. A gE-ELISA was used to detect PRV infection. The transmission of PRV was estimated from the number of contact infections and expressed as the reproduction ratio R. The inoculated pigs vaccinated with vaccine X shed significantly more virus than the inoculated pigs vaccinated with strain 783. However, despite the difference in virus excretion, the transmission of PRV between the two groups did not differ. We conclude that virus excretion is not an accurate measure for determining vaccine effectiveness. However, R of vaccine X (R = 0.98) was not significantly below one, whereas R of vaccine 783 (R = 0) was significantly below one. Consequently, we cannot exclude the possibility that major outbreaks of PRV occur among pigs vaccinated with vaccine X.  相似文献   

12.
The influence of vaccine genotype and route of administration on the efficacy of pseudorabies virus (PRV) vaccines against virulent PRV challenge was evaluated in a controlled experiment using five genotypically distinct modified live vaccines (MLVs) for PRV. Several of these MLVs share deletions in specific genes, however, each has its deletion in a different locus within that gene. Pigs were vaccinated with each vaccine, either via the intramuscular or intranasal route, and subsequently challenged with a highly virulent PRV field strain. During a 2-week period following challenge with virulent PRV, each of the vaccine strains used in this study was evaluated for its effectiveness in the reduction of clinical signs, prevention of growth retardation and virulent virus shedding. One month after challenge, tissues were collected and analyzed for virulent PRV latency load by a recently developed method for the electrochemiluminescent quantitation of latent herpesvirus DNA in animal tissues after PCR amplification. It was determined that all vaccination protocols provided protection against clinical signs resulting from field virus challenge and reduced both field virus shedding and latency load after field virus challenge. Our results indicated that vaccine efficacy was significantly influenced by the modified live vaccine strain and route of administration. Compared to unvaccinated pigs, vaccination reduced field virus latency load in trigeminal ganglia, but significant differences were found between vaccines and routes of administration. We conclude that vaccine genotype plays a role in the effectiveness of PRV MLVs.  相似文献   

13.
伪狂犬病病毒囊膜蛋白ISCOMs免疫原性测定   总被引：2，自引：1，他引：1  
应用伪狂犬病病毒囊膜蛋白与Quil A结合制备囊膜蛋白免疫刺激复合物(PRV-ISCOMs)，并通过ELISA、血清中和试验和淋巴细胞转化试验(Brdu-ELISA法)测定其诱导小鼠体液和细胞免疫应答水平。结果如下：1)小鼠分别接种3、7、10ug的PRV-ISCOMs后，于接种后PI7d血清中可测出ELISA IgG而抗体，随后抗体水平逐渐升高。间隔21d加强免疫后，FLISA IgG抗体水平进一步提高，且中和抗体效价均在1：22以上，而未加佐剂的囊膜蛋白对照组均无中和抗体；2)淋巴细胞转化试验初步结果表明PRV-ISCOMs能诱导小鼠的细胞免疫应答。3)免疫保护力测定显示免疫鼠能抵抗强毒攻击。上述结果表明PRV-ISCOMs具有良好的免疫原性，能诱导小鼠的体液免疫和细胞免疫应答。  相似文献   

14.
The avirulent Bartha's K strain of pseudorabies virus (PRV) was used to vaccinate 8 pigs at 10 weeks of age by the intransal route (experiment 1). On postvaccination days (PVD) 63 and 91, pigs were treated with corticosteroids. Viral shedding could not be detected. Explant cultures of trigeminal ganglia and tonsils did not produce virus. Four pigs with maternal antibody were vaccinated intranasally with Bartha's (attenuated) K strain of PRV at 10 weeks of age and were challenge exposed with a virulent strain of PRV on PVD 63 (experiment 2). Corticosteroid treatment, starting on postchallenge exposure day 70 (PVD 133) resulted in viral shedding in 1 of 4 pigs. In another pig of these 4, a 2nd corticosteroid treatment was required to trigger reactivation. In both pigs, sufficient reactivated virus was excreted to infect susceptible sentinel pigs. Restriction endonuclease analysis indicated that viruses isolated from the 2 pigs after challenge exposure and corticosteroid treatment were indistinguishable from the virulent virus. Evidence was not obtained for simultaneous excretion of vaccinal and virulent virus. Of 4 pigs without maternal antibody vaccinated twice with 1 of 2 inactivated PRV vaccines, challenge exposed on PVD 84, and treated with corticosteroids on postchallenge exposure day 63 (PVD 147), 1 was latently infected, as evidenced by the shedding of PRV (experiment 3). However, its sentinel pig remained noninfected.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
A modified-live pseudorabies virus (PRV) vaccine, designated PRV(dlg92/d1tk), with deletions in the thymidine kinase (tk) and glycoprotein-gIII (g92) genes, was derived from the PRV (Bucharest [BUK]-d13) vaccine strain. The vaccine virus also contained a deletion in glycoprotein gI. Despite 3 deletions, PRV(dlg92/d1tk) replicated to high titers in cell culture from 30 C to 39.1 C. Enzyme assays and autoradiography revealed that PRV(dlg92/d1tk) did not induce a functional tk activity in infected tk- RAB(BU) cells (rabbit skin). Rabbit skin cells were infected with PRV(dlg92/d1tk), with vaccine strains derived from BUK or Bartha K strains of PRV or with the virulent Illinois (ILL), Indiana-Funkhauser (IND-F), and Aujeszky (Auj) strains of PRV and were labeled with [3H]mannose from 4 or 5 to 24 hours after infection to investigate whether these viruses induced the synthesis of glycoprotein gIII. Nonionic detergent extracts were prepared and immunoprecipitated with antisera from pigs vaccinated with tk(-)-PRV(BUK-d13) or tk+-Bartha K, pigs vaccinated with tk+-PRV(BUK) strains and then challenge exposed to tk+-PRV(IND-F), naturally infected domestic or feral pigs, and pigs vaccinated with tk-)-PRV(dlg92/d1tk). Mouse monoclonal antibodies against PRV glycoproteins gIII, gp50, and gII were also studied. After immunoprecipitation, labeled PRV-specific proteins were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis and autoradiography. The PRV glycoprotein-gII complex, but not glycoprotein gIII, was synthesized in PRV(dlg92/d1tk)-infected cells. Glycoprotein gII and gIII were made in cells infected with PRV vaccine strains BUK, Bartha K, and BUK-d13 and with virulent PRV strains ILL, IND-F, and Auj. Cells infected with PRV(dlg92/d1tk) and with PRV strains ILL, IND-F, Auj, Bartha K, BUK, and BUK-d13, excreted into the cell culture medium a highly sulfated glycoprotein gX of about 90 kilodaltons. Antibodies to glycoprotein gIII were not detected in the sera of pigs inoculated with PRV(dlg92/d1tk), but were found in all other swine sera.  相似文献   

16.
乙型脑炎重组伪狂犬病病毒TK-/gG-/NS+1的安全性及免疫性   总被引：1，自引：0，他引：1  
用含有日本乙型脑炎病毒 (SA14 - 14 - 2株 )非结构蛋白 NS1基因的重组伪狂犬病病毒 TK- / g G- / NS 1 免疫BAL B/ c小鼠和断奶仔猪。结果表明 ,该重组病毒对 BAL B/ c小鼠和断奶仔猪是安全的 ,免疫的 BAL B/ c小鼠能抵抗伪狂犬病病毒 (PRV )强毒 (Ea株 )的致死性攻击 ,免疫的断奶仔猪能产生乙型脑炎病毒 (JEV)特异性抗体和 JEV特异性 CTL 活性。  相似文献   

17.
伪狂犬病病毒弱毒株LY株的分离鉴定   总被引：3，自引：1，他引：2  
从辽阳某猪场的10日龄仔猪中分离到1株病毒,经纯化后测得其毒价为107.29TCID50/mL.细胞中和试验表明,该病毒能被猪伪狂犬病病毒标准阳性血清所中和.电镜下可见到典型的疱疹病毒粒子,具有囊膜及外周纤突.所分离的病毒对氯仿、胰蛋白酶、乙醚敏感,在pH5.0～9.0下稳定,56℃ 30 min可以灭活.应用特异性引物,通过PCR能扩增出伪狂犬病病毒1 240 bp的gD基因.分离病毒对3日龄乳鼠有一定的致病力,但对家兔、3～5日龄仔猪及妊娠母猪都有很高的安全性.用不同剂量的病毒培养液肌肉注射于3～5日龄仔猪,14 d后用105.7TCID50伪狂犬病病毒强毒攻击,所有试验仔猪均可得到有效保护.用分离毒免疫母猪,其后代可获高滴度的母源抗体,15日龄的仔猪能抵抗105.7TCID50强毒的攻击.试验的结果初步说明,所分离的病毒为伪狂犬病病毒(命名为PRV LY株),并可能是一株弱毒株,而且具有很好的免疫保护作用.  相似文献   

18.
Mice and swine inoculated subcutaneously with culture filtrate vaccine prepared from acriflavine-fast attenuated Erysipelothrix rhusiopathiae strain Koganei 65-0.15 (serovar 2), were challenge exposed to 20 pathogenic strains of E rhusiopathiae of 18 serovars and type N. Vaccinated mice survived after challenge exposure to serovars 1b, 2, 8 (strain Goda), and type N, but mortality occurred in vaccinated mice challenge exposed to other strains: 20% to 30% mortality in mice challenge exposed to serovars 1a, 11, 12, 15, 16, or 21; 40% to 50% mortality in mice challenge exposed to serovars 4, 5, 6, 7, or 8 (strain 911); and 60% to 80% mortality in mice challenge exposed to serovars 9, 10, 18, or 19. All vaccinated mice died after challenge exposure with strain 2553 (serovar 20). Non-vaccinated control mice died after challenge exposure to all strains. Of 2 vaccinated swine challenge exposed to strain 2553, 1 developed a local urticarial lesion at the site of intradermal exposure. Vaccinated swine challenge exposed to serovars 1a, 1b, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 18, 19, 21, or type N did not have clinical signs of acute erysipelas. Nonvaccinated control swine developed acute generalized erysipelas or localized urticarial lesions at the site of intradermal exposure.  相似文献   

19.
The aim of this study was to investigate the effects of a porcine reproductive and respiratory syndrome virus (PRRSV) infection on the development of the immune response after pseudorabies virus (PRV) vaccination in pigs. Pigs were intranasally inoculated with the European PRRSV strain, Lelystad virus ter Huurne, and were vaccinated intramuscularly with PRV 2 weeks later (LV-PRV group). Control pigs were vaccinated with PRV only (PRV group). Eight weeks after PRV vaccination, pigs from both groups were challenged intranasally with wild-type PRV. We measured the lymphoproliferative, and the cytolytic responses to PRV of peripheral blood mononuclear cells (PBMC), isolated from blood samples. In addition, serum samples were examined for antibodies against PRV and LV. One week after PRV vaccination, PBMC proliferated abundantly to PRV in both groups. However, in the LV-PRV group the lymphoproliferative response declined after 1 week, whereas, in the PRV group, the lymphoproliferative response was high for 3 weeks and declined thereafter (P<0.05). After challenge, the lymphoproliferative response was 1 week earlier and was consistently and significantly higher in the PRV group than in the LV-PRV group. The PRV-specific killing was higher at 3 weeks after PRV vaccination and 5 weeks after PRV challenge 19+/-3 and 24+/-6%, respectively, in the PRV group, compared to 7+/-4 and 6+/-9%, respectively, in the LV-PRV group (P<0.05). However, later after vaccination and challenge the cytolytic response was identical in both groups. The antibody titre against PRV developed equally in both groups. After challenge, no PRV virus was isolated from both groups. From these results we conclude that, although PRRSV infection did cause changes in the time course of the T-lymphocyte response after PRV vaccination, PRRSV infection did not inhibit the development of vaccine-induced protection after PRV.  相似文献   

20.
Three gilts were vaccinated with a NYVAC vaccinia recombinant expressing glycoprotein gD of pseudorabies virus (PRV) (NYVAC/gD). After farrowing, the piglets were allowed to nurse normally to obtain colostral immunity and then were divided into four groups, receiving NYVAC/gD, a NYVAC recombinant expressing glycoprotein gB of PRV (NYVAC/gB), an inactivated PRV vaccine (iPRV), or no vaccine. The piglets were vaccinated twice, three weeks apart beginning at approximately two weeks of age and later challenged with virulent PRV oronasally. Piglets that received NYVAC/gB or iPRV were the best protected based on lack of mortality, lower temperature responses, decreased weight loss and decreased viral shedding after challenge. These results indicate effective strategies for stimulating active immune response while still under the protection of maternal immunity.  相似文献   

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