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1.
Two US swine influenza virus (SIV) isolates, A/Swine/Iowa/15/1930 H1N1 (IA30) and A/Swine/Minnesota/00194/2003 H1N2 (MN03), were evaluated in an in vivo vaccination and challenge model. Inactivated vaccines were prepared from each isolate and used to immunize conventional pigs, followed by challenge with homologous or heterologous virus. Both inactivated vaccines provided complete protection against homologous challenge. However, the IA30 vaccine failed to protect against the heterologous MN03 challenge. Three of the nine pigs in this group had substantially greater percentages of lung lesions, suggesting the vaccine potentiated the pneumonia. In contrast, priming with live IA30 virus provided protection from nasal shedding and virus replication in the lung in MN03 challenged pigs. These data indicate that divergent viruses that did not cross-react serologically did not provide complete cross-protection when used in inactivated vaccines against heterologous challenge and may have enhanced disease. In addition, live virus infection conferred protection against heterologous challenge.  相似文献   

2.
A commercial indirect swine influenza virus (SIV) H1N1 enzyme-linked immunosorbent assay (ELISA) was compared with the hemagglutination inhibition (HI) assay by testing 72 samples from experimentally infected pigs and 780 field samples of undefined SIV status. The HI assay was performed using SIV isolates A/Swine/IA/73 for H1N1 and A/Swine/IA/8548-1/98 for H3N2. The ELISA used an SIV isolated in 1988. The results showed that HI and ELISA detected an antibody in 11 and 6, respectively, of 72 serum samples collected from pigs experimentally infected with a 1992 SIV isolate (A/Swine/IA/40776/92). The presence of antibodies in these experimental samples was confirmed by HI tests in which all 72 samples were positive against the homologous virus, a more recent H1N1 SIV isolate (A/Swine/NVSL/01) supplied by National Veterinary Services Laboratories, Ames, Iowa, and a 1999 H1N1 isolate currently used in a commercial vaccine. On testing 780 field samples, an overall agreement of 85.5% was generated between the HI and ELISA. This study demonstrated that the ELISA is a useful serodiagnostic screening test at herd level for detecting swine antibodies against SIV. However, a new SIV isolate representing current SIV strains circulating in the field is needed to replace the older isolates used in the HI and ELISA to increase the test accuracy for serodiagnosis of SIV.  相似文献   

3.
The efficacy of a commercial swine influenza vaccine based on A/New Jersey/8/76 (H1N1) and A/Port Chalmers/1/73 (H3N2) strains was tested against challenge with an H1N2 swine influenza virus. Influenza virus-seronegative pigs were vaccinated twice with the vaccine when they were four and eight weeks old, or with the same vaccine supplemented with an H1N2 component. Control pigs were left unvaccinated. Three weeks after the second vaccination, all the pigs were challenged intratracheally with the swine influenza strain Sw/Gent/7625/99 (H1N2). The commercial vaccine induced cross-reactive antibodies to H1N2, as detected by the virus neutralisation (VN) assay, but VN antibody titres were 18 times lower than in the pigs vaccinated with the H1N2-supplemented vaccine. The challenge produced severe respiratory signs in nine of 10 unvaccinated control pigs, which developed high H1N2 virus titres in the lungs 24 and 72 hours after the challenge. Vaccination with the commercial vaccine resulted in milder respiratory signs, but H1N2 virus replication was not prevented. Mean virus titres in the pigs vaccinated with the commercial vaccine were 1-5 log10 lower than in the controls at 24 hours but no different at 72 hours. In contrast, the H1N2-supplemented vaccine prevented respiratory disease in most pigs. There was a 4-5 log10 reduction in the mean virus titre at 24 hours in the pigs vaccinated with this vaccine, and no detectable virus replication at 72 hours. These data indicate that the commercial swine influenza vaccine did not confer adequate protection against the H1N2 subtype.  相似文献   

4.
Sows and gilts lack immunity to human adenovirus 5 (Ad-5) vectored vaccines so immunogens of swine pathogens can be expressed with these vaccines in order to immunize suckling piglets that have interfering, maternally derived antibodies. In this study 7-day-old piglets, that had suckled H3N2 infected gilts, were sham-inoculated with a non-expressing Ad-5 vector or given a primary vaccination with replication-defective Ad-5 viruses expressed the H3 hemagglutinin and the nucleoprotein of swine influenza virus (SIV) subtype H3N2. The hemagglutination inhibition (HI) titer of the sham-inoculated group (n = 12) showed continued antibody decay whereas piglets vaccinated with Ad-5 SIV (n = 23) developed an active immune response by the second week post-vaccination. At 4 weeks-of-age when the HI titer of the sham-inoculated group had decayed to 45, the sham-inoculated group and half of the Ad-5 SIV vaccinated pigs were boosted with a commercial inactivated SIV vaccine. The boosted pigs that had been primed in the presence of maternal interfering antibodies had a strong anamnestic response while sham-inoculated pigs did not respond to the commercial vaccine. Two weeks after the booster vaccination the pigs were challenged with a non-homologous H3N2 virulent SIV. The efficacy of the vaccination protocol was demonstrated by abrogation of clinical signs, by clearance of challenge virus from pulmonary lavage fluids, by markedly reduced virus shedding in nasal secretions, and by the absence of moderate or severe SIV-induced lung lesions. These recombinant Ad-5 SIV vaccines are useful for priming the immune system to override the effects of maternally derived antibodies which interfere with conventional SIV vaccines.  相似文献   

5.
This study investigated the efficacy of a bivalent swine influenza virus (SIV) vaccine in piglets challenged with a heterologous H1N1 SIV isolate. The ability of maternally derived antibodies (MDA) to provide protection against a heterologous challenge and the impact MDA have on vaccine efficacy were also evaluated. Forty-eight MDA(+) pigs and 48 MDA(-) pigs were assigned to 8 different groups. Vaccinated pigs received two doses of a bivalent SIV vaccine at 3 and 5 weeks of age. The infected pigs were challenged at 7 weeks of age with an H1N1 SIV strain heterologous to the H1N1 vaccine strain. Clinical signs, rectal temperature, macroscopic and microscopic lesions, virus excretion, serum and local antibody responses, and influenza-specific T-cell responses were measured. The bivalent SIV vaccine induced a high serum hemagglutination-inhibition (HI) antibody titer against the vaccine virus, but antibodies cross-reacted at a lower level to the challenge virus. This study determined that low serum HI antibodies to a challenge virus induced by vaccination with a heterologous virus provided protection demonstrated by clinical protection and reduced pneumonia and viral excretion. The vaccine was able to prime the local SIV-specific antibody response in the lower respiratory tract as well as inducing a systemic SIV-specific memory T-cell response. MDA alone were capable of suppressing fever subsequent to infection, but other parameters showed reduced protection against infection compared to vaccination. The presence of MDA at vaccination negatively impacted vaccine efficacy as fever and clinical signs were prolonged, and unexpectedly, SIV-induced pneumonia was increased compared to pigs vaccinated in the absence of MDA. MDA also suppressed the serum antibody response and the induction of SIV-specific memory T-cells following vaccination. The results of this study question the effectiveness of the current practice of generating increased MDA levels through sow vaccination in protecting piglets against disease.  相似文献   

6.
An alphavirus derived replicon particle (RP) vaccine expressing the cluster IV H3N2 swine influenza virus (SIV) hemagglutinin (HA) gene induced protective immunity against homologous influenza virus challenge. However, pigs with maternal antibody had no protective immunity against challenge after vaccination with RP vaccines expressing HA gene alone or in combination with nucleoprotein gene.  相似文献   

7.
Antigenic drift of swine influenza A (H3N2) viruses away from the human A/Port Chalmers/1/73 (H3N2) strain, used in current commercial swine influenza vaccines, has been demonstrated in The Netherlands and Belgium. Therefore, replacement of this human strain by a more recent swine H3N2 isolate has to be considered. In this study, the efficacy of a current commercial swine influenza vaccine to protect pigs against a recent Dutch field strain (A/Sw/Oedenrode/96) was assessed. To evaluate the level of protection induced by the vaccine it was compared with the optimal protection induced by a previous homologous infection. Development of fever, virus excretion, and viral transmission to unchallenged group mates were determined to evaluate protection. The vaccine appeared efficacious in the experiment because it was able to prevent fever and virus transmission to the unchallenged group mates. Nevertheless, the protection conferred by the vaccine was sub-optimal because vaccinated pigs excreted influenza virus for a short period of time after challenge, whereas naturally immune pigs appeared completely protected. The immune response was monitored, to investigate why the vaccine conferred a sub-optimal protection. The haemagglutination inhibiting and virus neutralising antibody responses in sera, the nucleoprotein-specific IgM, IgG, and IgA antibody responses in sera and nasal secretions and the influenza-specific lymphoproliferation responses in the blood were studied. Vaccinated pigs developed the same or higher serum haemagglutination inhibiting, virus neutralising, and nucleoprotein-specific IgG antibody titres as infected pigs but lower nasal IgA titres and lymphoproliferation responses. The lower mucosal and cell-mediated immune responses may explain why protection after vaccination was sub-optimal.  相似文献   

8.
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   

9.
Humoral and cellular immune responses to inactivated swine influenza virus (SIV) vaccine were evaluated and compared. Fifty 3-week-old weaned pigs were randomly divided into the non-vaccinated control group and vaccinated group containing 25 pigs each. Pigs were vaccinated intramuscularly twice with adjuvanted UV-inactivated A/SW/MN/02011/08 (MN/08) H1N2 SIV vaccine at 6 and 9 weeks of age. Whole blood samples for multi-parameter flow cytometry (MP-FCM) and serum samples for hemagglutination inhibition (HI) assay were collected at 23 and 28 days after the second vaccination, respectively. A standard HI assay and MP-FCM were performed against UV-inactivated homologous MN/08 and heterologous pandemic A/CA/04/2009 (CA/09) H1N1 viruses. While the HI assay detected humoral responses only to the MN/08 virus, the MP-FCM detected strong cellular responses against the MN/08 virus and significant heterologous responses to the CA/09 virus, especially in the CD4+CD8+ T cell subset. The cellular heterologous responses to UV-inactivated virus by MP-FCM suggested that the assay was sensitive and potentially detected a wider range of antigens than what was detected by the HI assay. Overall, the adjuvanted UV-inactivated A/SW/MN/02011/08 H1N2 SIV vaccine stimulated both humoral and cellular immune responses including the CD4-CD8+ T cell subset.  相似文献   

10.
OBJECTIVE: To evaluate the safety and efficacy of a human adenovirus-5 vaccine for protecting weaned pigs against swine influenza virus subtype H3N2 infection when administered via 2 injection methods. ANIMALS: 76 pigs. PROCEDURE: 6 groups of weaned pigs received a 10-fold serial dilution of recombinant adenovirus expressing H3 hemagglutinin and a constant amount of recombinant adenovirus expressing nucleoprotein, either via a needle-free injection device or by traditional IM injection. In each group of 10 pigs, 1 served as a nonvaccinated contact pig to monitor whether there was spread of vaccinial virus from pig to pig. Vaccinated pigs and nonvaccinated controls were challenged or sham-inoculated 5 weeks later. After challenge, pigs were observed for clinical signs and nasal secretions were tested for virus. On day 5 after challenge, pigs were euthanatized; lungs were examined for gross lesions, and bronchoalveolar lavage specimens were tested for virus replication. RESULTS: A hemagglutination inhibition (HI) antibody response was elicited in a dose-dependent manner. Traditional IM administered vaccination induced consistently higher HI antibody responses than vaccination via needle-free injection, but the differences were not significant. Likewise, traditional IM administration was superior at reducing nasal virus shedding except at the highest dose, at which both methods blocked virus replication. The severity of lung lesions was reduced in a dose-dependent manner by both vaccination methods. Sentinel pigs did not seroconvert. CONCLUSIONS AND CLINICAL RELEVANCE: The human adenovirus-5 vaccine at high doses prevented nasal virus shedding after challenge exposure with both methods of administration. The replication-defective vaccine virus was not transmitted to sentinel pigs.  相似文献   

11.
Groups of pigs vaccinated with an inactivated bivalent vaccine containing porcine parvovirus (PPV) and pseudorabies virus (PRV) developed geometric mean titers (GMT) of humoral antibody for each of the viruses as high or slightly higher than those of other groups of pigs that were vaccinated with inactivated monovalent vaccines containing one or the other of the same viruses. An increase in GMT after challenge exposure of vaccinated pigs to live virus indicated that vaccination did not prevent virus replication. However, an indication that replication was less extensive in vaccinated pigs was provided by the following. Although neither vaccinated nor nonvaccinated (control) pigs had clinical signs after exposure to the live PPV, the effect of vaccination was evident by the fact that GMT were higher in nonvaccinated pigs after exposure than they were in vaccinated pigs. Conversely, all pigs exposed to live PRV had clinical signs, but these signs varied between mild-to-moderate and transient for vaccinated pigs to severe and fatal for nonvaccinated pigs.  相似文献   

12.
Intratracheal inoculation of a field isolate of influenza A H1N1 caused high fever, anorexia and dyspnoea in unvaccinated pigs. In a limited study, it was shown that animals vaccinated once with an inactivated influenza A H1N1 strain showed partial protection at challenge, indicated by mild or absent clinical signs and by the suppression of viral replication. There appeared to be a correlation between the hemagglutination-inhibition titers of the serum of vaccinated pigs and the degree of protection. Animals vaccinated with two spaced injections were completely protected at challenge. Viral replication was inhibited in their respiratory tract since no virus was isolated from animals at slaughter and no increase in antibody titer was observed in challenged vaccinates followed serologically. It was concluded that vaccination of swine against influenza with an inactivated vaccine can result in a protective immunity in the respiratory tract. The New Jersey vaccine strain could protect against swine influenza strains (H1N1) currently prevalent in several European countries.  相似文献   

13.
Swine serologically negative for anti-Leptospira antibodies were given 2 doses of a pentavalent vaccine (3 weeks between doses) prepared from Leptospira serovars canicola, icterohaemorrhagiae, hardjo, pomona, and grip-potyphosa (0.2 mg/serovar/dose). Leptospires used for vaccinal production were cultivated in a protein-free medium or in a bovine albumin-containing medium. All vaccinated swine had demonstrable antibody titers within 1 week of the initial vaccination. Peak microscopic agglutination titers were between 256 and 1,024 after the 2nd vaccinal dose was given. After challenge exposure with serovar canicola, control swine had titers of at least 13,653 and the vaccinated swine had titers of 3,403 to 8,192, depending on the vaccine. Leptospiremia and kidney infections were not detected in any canicola Moulton immunized swine, but did appear in control swine. The Al(OH)3 adjuvant had no obvious influence of any of the vaccinal titers.  相似文献   

14.
为了解华南地区猪群中猪流感病毒(SIV)的流行及其遗传变异情况,本研究从2016年~2017年广东、广西等地猪群236份猪肺脏病料组织和143份鼻拭子样品中分离鉴定得到3株SIV,全基因组测序和遗传演化分析结果显示,3个分离株均属于H1N1亚型欧亚类禽分支SIV,并且均与pdm09分支病毒株发生了重组。HA蛋白分子特征分析结果显示,A/Swine/Guangxi/NK/2016 HA蛋白第23位糖基化位点发生了缺失。3265份血清样品抗体监测结果显示,欧亚类禽H1N1、pdm09 H1N1和H3N2 SIV的血清抗体阳性率分别为27.53%、20.98%和34.85%。另外,0.64%的(21份)血清样品为H9N2亚型流感病毒抗体阳性,并且猪群中不同亚型和不同分支SIV之间混合感染的情况非常普遍。猪群中流感病毒血清抗体监测结果显示,EA H1N1、pdm09和H3N2亚型SIV HI抗体滴度最高均可达到1:1280,而H9N2亚型HI抗体滴度最高为1:160,表明H9N2 AIV虽然可以感染猪,但对猪还不适应。各月份的血清抗体阳性率分析显示,SIV的流行具有季节性,冬季(11月、12月和1月份)的流行最为严重。本研究可为华南地区猪群SI防控及疫苗株的筛选提供参考依据。  相似文献   

15.
Swine influenza virus is an economically important pathogen to the U.S. swine industry. New influenza subtypes and isolates within subtypes with different genetic and antigenic makeup have recently emerged in U.S. swineherds. As a result of the emergence of these new viruses, diagnosticians' ability to accurately diagnose influenza infection in pigs and develop appropriate vaccine strategies has become increasingly difficult. The current study compares the ability of subtype-specific commercial enzyme-linked immunosorbent assays (ELISA), hemagglutination inhibition (HI), and serum neutralization (SN) assays to detect antibodies elicited by multiple isolates within different subtypes of influenza virus. Pigs were infected with genetically and antigenically different isolates of the 3 major circulating subtypes within populations of swine (H1N1, H1N2, and H3N2). Serum was collected when all pigs within a group collectively reached HI reciprocal titers >or=160 against that group's homologous challenge virus. The antibody cross-reactivity of the sera between isolates was determined using ELISA, HI, and SN assays. In addition, the correlation between the 3 assays was determined. The assays differed in their ability to detect antibodies produced by the viruses used in the study. The results provide important information to diagnostic laboratories, veterinarians, and swine producers on the ability of 3 common serological assays used in identifying infection with influenza in pigs.  相似文献   

16.
Swine influenza viruses (SwIVs) cause considerable morbidity and mortality in domestic pigs, resulting in a significant economic burden. Moreover, pigs have been considered to be a possible mixing vessel in which novel strains loom. Here, we developed and evaluated a novel M2e-multiple antigenic peptide (M2e-MAP) as a supplemental antigen for inactivated H3N2 vaccine to provide cross-protection against two main subtypes of SwIVs, H1N1 and H3N2. The novel tetra-branched MAP was constructed by fusing four copies of M2e to one copy of foreign T helper cell epitopes. A high-yield reassortant H3N2 virus was generated by plasmid based reverse genetics. The efficacy of the novel H3N2 inactivated vaccines with or without M2e-MAP supplementation was evaluated in a mouse model. M2e-MAP conjugated vaccine induced strong antibody responses in mice. Complete protection against the heterologous swine H1N1 virus was observed in mice vaccinated with M2e-MAP combined vaccine. Moreover, this novel peptide confers protection against lethal challenge of A/Puerto Rico/8/34 (H1N1). Taken together, our results suggest the combined immunization of reassortant inactivated H3N2 vaccine and the novel M2e-MAP provided cross-protection against swine and human viruses and may serve as a promising approach for influenza vaccine development.  相似文献   

17.
A challenge study was conducted to evaluate the safety and efficacy of an inactivated influenza H3N2 virus vaccine combined with Quil A/Alhydrogel mixture under controlled conditions in piglets. Twenty-four piglets from 12 sows were allocated to 2 groups; injected intramuscularly with 2 doses of the tested vaccine or with PBS at 2 wk intervals and challenged intratracheally with 105TCID50 of the H3N2 swine influenza virus 6 d after the 2nd immunization. Clinical and virological parameters were recorded for 4 d after the challenge. The use of the tested vaccine produced high serum hemagglutination-inhibition titers against the swine H3N2 strain virus. This strong immune response suppressed all clinical signs and viral shedding and reduced pulmonary lesions due to the challenge in the vaccinated group, without causing any secondary effects. Our results suggest that the serum HI titers correlated with the degree of protection induced by an inactivated swine influenza H3N2 vaccine.  相似文献   

18.
H1N1 and H3N2 are the dominant subtypes causing swine influenza in China and other countries. It is important to develop effective vaccines against both H1N1 and H3N2 subtypes of swine influenza virus (SIV). We examined the effects of a DNA vaccine expressing an influenza HA fused to three copies of murine complement C3d in mice. Plasmids encoding soluble HA (sHA), complete HA (tmHA), or a soluble fused form of HA (sHA-mC3d3) were constructed from the H3N2 subtype of SIV. The immune response was monitored by an enzyme-linked immunosorbent assay (ELISA), hemagglutination inhibition (HI) assays, and virus neutralization tests. Analysis of antibody titers indicated that immunization with HA-mC3d3 resulted in higher titers of anti-HA antibodies and higher antibody affinities, compared with serum from mice immunized with sHA or tmHA. Furthermore, the C3d fusion increased the Th2-biased immune response, by inducing IL-4 production. Splenocytes from mice immunized with sHA-mC3d3 produced about three-fold more IL-4 than did splenocytes from mice immunized with sHA or tmHA. Seven days post-challenge with homologous virus (H3N2), no virus was isolated from the mice immunized with HA-expressing plasmids. However, 10 days post-challenge with heterologous virus (H1N1), only mice immunized with sHA-mC3d3 had no virus or microscopic lesions in the kidneys and cerebrum. In conclusion, C3d enhanced antibody responses to hemagglutinin and protective immunity against SIV of different subtypes.  相似文献   

19.
应用本实验室构建的嵌合型猪圆环病毒（PCV1—2）及真核表达质粒pcDNA3．1／V5-His-ORF2作为免疫原免疫母源抗体ELISA效价在0．07～0．60不等的商品猪,9头猪随机分为4组,1组（3头）肌肉注射免疫10^3.5 TCID50的PCV1-2／头,2组（2头）肌肉注射真核表达质粒200μg／头,3组（2头）肌肉注射空载体（pcDNA3．1）200μg／头,4组（2头）不免疫作为攻毒对照组。于免疫后42d,PCV1—2组及真核表达质粒组产生了PCV2抗体。免疫后42d所有组攻毒PCV2和PRRSV,剂量分别为2×10^4.5 TCID50／头和10^6 TCID50／头。攻毒后21d,攻毒对照组猪淋巴结比免疫组显著肿大,免疫组猪血清、淋巴结中PCV2病毒栽量低于对照组,攻毒对照组猪淋巴结中PCV2抗原含量高于免疫组。这些结果表明,嵌合型PCV1-2及真核表达质粒肌肉注射免疫商品猪后,对PCV2感染能产生保护性免疫应答,有可能成为候选疫苗。  相似文献   

20.
Because it is expected to induce cross-reactive serum and mucosal antibody responses, mucosal vaccination against highly pathogenic avian influenza (HPAI) is potentially superior to conventional parenteral vaccination. Here, we tested whether intraocular vaccination with an inactivated AI virus induced protective antibody responses in chickens. Chickens were inoculated intraocularly twice with 104 hemagglutination units of an inactivated H5N1 HPAI virus. Four weeks after the second vaccination, the chickens were challenged with a lethal dose of the homologous H5N1 HPAI virus. Results showed that most of the vaccinated chickens mounted positive antibody responses. The median serum hemagglutination inhibition titer was 1:80. Addition of CpG oligodeoxynucleotide 2006 or cholera toxin to the vaccine did not enhance serum antibody titers. Cross-reactive anti-hemagglutinin IgG, but not IgA, was detected in oropharyngeal secretions. In accordance with these antibody results, most vaccinated chickens survived a lethal challenge with the H5N1 HPAI virus and did not shed the challenge virus in respiratory or digestive tract secretions. Our results show that intraocular vaccination with an inactivated AI virus induces not only systemic but also mucosal antibody responses and confers protection against HPAI in chickens.  相似文献   

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