Intranasal vaccination of pigs against Aujeszky's disease. 4. Comparison with one or two doses of an inactivated vaccine in pigs with moderate maternal antibody titres

Intranasal (IN) vaccination of pigs with low levels of maternally-derived antibody (MDA) has previously been shown to confer good protection against challenge with virulent Aujeszky's disease virus (ADV). The objective of the present study was to determine the efficacy of IN vaccination with an attenuated ADV, in comparison with that of an inactivated vaccine given parenterally, in pigs with higher MDA titres at the time of vaccination. In one experiment, vaccinations were done at 6 weeks of age, and in another experiment pigs were vaccinated at 4 and/or 9 weeks of age. Two months after (the last) vaccination pigs were challenged intranasally with a virulent ADV. Protection was evaluated on the basis of mortality, periods of growth arrest, fever and virus shedding after challenge. The presence of MDA markedly depressed the serum-neutralizing antibody response after vaccination. Sensitisation occurred after parenteral vaccination with an inactivated vaccine despite high MDA levels. Although the intranasally-vaccinated pigs had lower levels of neutralizing antibody at the time of challenge, they were significantly better protected than pigs given 1 or 2 doses of the inactivated vaccine. Comparing the present results with those of a previous study, it appears that the efficacy of parenteral as well as intranasal ADV vaccination decreases with increasing levels of MDA at the time of vaccination.     

Limited efficacy of West Nile virus vaccines in large falcons (Falco spp.)

West Nile virus (WNV) can lead to fatal diseases in raptor species. Unfortunately, there is no vaccine which has been designed specifically for use in breeding stocks of falcons. Therefore the immunogenicity and protective capacity of two commercially available WNV vaccines, both approved for use in horses, were evaluated in large falcons. One vaccine contained adjuvanted inactivated WNV lineage 1 immunogens, while the second represented a canarypox recombinant live virus vector vaccine. The efficacy of different vaccination regimes for these two vaccines was assessed serologically and by challenging the falcons with a WNV strain of homologous lineage 1. Our studies show that the recombinant vaccine conveys a slightly better protection than the inactivated vaccine, but moderate (recombinant vaccine) or weak (inactivated vaccine) side effects were observed at the injection sites. Using the recommended 2-dose regimen, both vaccines elicited only sub-optimal antibody responses and gave only partial protection following WNV challenge. Better results were obtained for both vaccines after a third dose, i.e. alleviation of clinical signs, absence of fatalities and reduction of virus shedding and viraemia. Therefore the consequences of WNV infections in falcons can be clearly alleviated by vaccination, especially if the amended triple administration scheme is used, although side effects at the vaccination site must be accepted.     

The immune response and maternal antibody interference to a heterologous H1N1 swine influenza virus infection following vaccination

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.     

Antibody responses of guinea-pigs, rabbits and pigs to inactivated porcine parvovirus vaccines

Antibody responses were compared in guinea-pigs, rabbits and pigs following vaccination with inactivated porcine parvovirus (PPV) vaccines. Mean PPV hemagglutination inhibition (HI) antibody titers of 52, 56 and 36 at 1 week after first vaccination and 896, 640 and 512 at 2 weeks after second vaccination were detected in guinea-pigs, rabbits and pigs, respectively. PPV vaccines prepared with greater concentrations of virus, as determined by hemagglutination (HA) units, and of aluminum hydroxide gel adjuvant, induced higher HI antibody titers in guinea-pigs. Optimal concentrations for inducing consistently high antibody titers consisted of vaccine virus with a HA titer of 256/0.1 ml and gel adjuvant at a final concentration of 50%. A second vaccination at 4 weeks compared to 2 or 3 weeks after first vaccination resulted in higher mean HI titers. These data provide preliminary information on the use of guinea-pigs or rabbits as laboratory animal models for testing the potency of PPV vaccines.     

The effects of challenge on the humoral and cellular immune responses in pseudorabies vaccinated swine.

The effects of challenge exposure on the humoral and cellular immune responses in pseudorabies vaccinated swine were studied in 84 barrows. The pigs were divided into seven groups and challenge exposed to a virulent strain of pseudorabies virus on months 1, 3, 5, 8, 10, 12 and 14 after vaccination. The pigs were vaccinated with commercial attenuated and inactivated pseudorabies virus vaccines. The protection conferred by vaccination was equally effective with both types of vaccines. The levels of cellular and humoral immunity after challenge exposure in pigs vaccinated with either type of vaccine were similar. The cell-mediated immune response can be effectively used for the early detection of pigs exposed to pseudorabies virus. Virus isolation attempts from the brain and spleen in most of the vaccinated pigs were unsuccessful.     

Sequential changes in the humoral immune response of pigs to pseudorabies virus after vaccination, exposure to virulent virus, and reactivation of latent virus

Sequential changes in the humoral immune response of pigs to pseudorabies virus (PRV) after each of several exposures to the virus were evaluated by determining virus neutralization (VN) and radioimmunoprecipitation (RIP) activities of sera collected at selected intervals. Pigs were vaccinated intramuscularly with live attenuated virus (6 pigs), inactivated attenuated virus (6 pigs), or inactivated virulent virus (6 pigs). All pigs were challenged oronasally with virulent virus 3 weeks later and 12 (4 pigs of each vaccine group) were subsequently treated with dexamethasone in an attempt to reactivate latent virus. The relatively low serum titers of VN antibody that were raised by vaccination (titers ranged from 2 to 32) increased markedly (at least 16-fold) for all pigs after exposure to virulent virus. After dexamethasone treatment, the VN titers of 2 pigs increased 16-fold, whereas those of the other 10 dexamethasone-treated pigs and the 6 nontreated pigs either remained the same or increased only minimally (i.e., no more than 2-fold). The results of RIP using 35S-methionine-labeled viral proteins were initially similar to those of VN in that the low levels of serum RIP activity detected after vaccination increased markedly after subsequent exposure to virulent virus. In contrast to VN, however, most pigs (11 of 12) treated with dexamethasone had a clear increase in serum RIP activity. The increase was particularly striking for viral proteins of relatively low (less than 46K) molecular weight. Precipitating activity for 14C-glucosamine-labeled viral glycoproteins was not detected until after pigs were exposed to virulent virus. The increase in RIP activity detected after dexamethasone treatment was likely due to an additional antigenic stimulus associated with virus reactivation. However, virus was isolated from nasal swabs of only 4 of the 12 treated pigs. None of the results appeared to be affected appreciably by the type of vaccine used for initial immunization.     

Role of memory B-cell responses in serum and mucosal fluids of swine for protective immunity against pseudorabies virus.

We examined primary and memory isotype-specific antibody responses directed against pseudorabies virus in serum and mucosal fluids of pigs with and without passively acquired maternal antibody, and we studied the relationship between these responses and protection against virus challenge. Pigs were inoculated intranasally with the virulent NIA-3 strain or the avirulent Bartha strain, or they were inoculated IM with an inactivated vaccine containing the Phylaxia strain. Ten weeks later, all pigs were challenge-exposed intranasally with strain NIA-3. Only pigs that were without passively acquired antibody at the time they were inoculated with virulent virus appeared to have complete protective immunity against challenge exposure, as evidenced by lack of clinical signs of pseudorabies and lack of virus excretion. In contrast, pigs inoculated with strain Bartha or with the inactivated vaccine developed fever, had a period of growth arrest, and excreted virus after challenge exposure. In pigs without passively acquired antibody, intranasal inoculation with strains NIA-3 or Bartha was followed by primary IgM and IgA responses in serum and in oropharyngeal fluid as well as primary IgG1 and IgG2 responses in serum. Intramuscular inoculation with the inactivated vaccine induced primary serum IgM, IgG1, and IgG2 responses, but no mucosal responses. Challenge exposure of pigs that had been inoculated with the Bartha strain or the inactivated vaccine was followed by clear memory responses in serum and in oropharyngeal fluid. In contrast, challenge exposure of pigs that had been inoculated by the virulent NIA-3 strain was not followed by memory responses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Intranasal vaccination of pigs against Aujeszky's disease: comparison with inactivated vaccines in pigs with low maternal antibody titres

Intranasal vaccination with an attenuated Aujeszky's disease virus strain was compared with parenteral vaccination with two inactivated virus vaccines, in 10-week-old pigs with low levels of maternal antibody. Intranasal vaccination conferred a much better protection than parenteral vaccination with the two inactivated vaccines against challenge two months later, as evidenced by shorter periods of growth arrest and fever and a greater reduction of virulent virus shedding after challenge-exposure.     

Evaluation in swine of a subunit vaccine against pseudorabies

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.     

Is there a benefit from an early booster vaccination in the control of equine influenza?

Conventional equine influenza vaccination schedules consist of a primary course of two vaccinations given 4-6 weeks apart followed by a third vaccination (booster) given approximately 5 months later. In between the primary course and the third vaccination, horses are generally considered not to be adequately protected against influenza. This study aimed to investigate whether Thoroughbred foals would benefit from a vaccination schedule in which the third vaccination was given earlier than in conventional vaccination schedules. The vaccines used were an inactivated whole virus equine influenza vaccine and an inactivated whole virus combination vaccine containing equine influenza and equine herpesvirus antigens. Four groups of foals were vaccinated with the two vaccines according to a conventional and an accelerated vaccination schedule in which the third vaccination was given 14 weeks after the first administration. In both groups, the fourth vaccination was given at the normally recommended interval of 26 weeks after the third vaccination for the combination vaccine and 52 weeks after the third vaccination with the influenza only vaccine. The horses were 4-11 months of age and seronegative for influenza. Immunological responses after vaccination were monitored for several months using the single radial haemolysis test. The results indicated that 28 weeks after the first vaccination, antibody levels in horses vaccinated according to the accelerated schedule were not significantly higher than in horses vaccinated according to the conventional schedule. In addition, the total level of antibody production (area under the curve) was not significantly different at that point although antibody titres were slightly higher (but not significantly so) between 16-30 weeks in the accelerated schedule. Between the third and fourth doses, horses vaccinated according to the accelerated schedule had antibodies against influenza below the level required for clinical protection for 39 and 18 weeks for the influenza only and the combination vaccine, respectively, whereas those vaccinated according to the conventional schedule had antibody titres below the level for clinical protection for 9-15 weeks in the corresponding period for both vaccines. Horses vaccinated according to the accelerated schedule with the combination vaccine had lower antibody titres after the fourth vaccination than those vaccinated according to the conventional schedule after the third vaccination, although antibody titres prior to vaccination were similar. For the influenza only vaccine, titres after the accelerated fourth administration were not different to those after the conventional third vaccination. There was no benefit from early booster vaccinations with the vaccines used in this study, so for these vaccines the conventional schedule provided better protection than the selected accelerated alternative. This may contrast with some other vaccine formulations, although a direct comparison using similar protocols has not been made.     

Duration of the protection of an E2 subunit marker vaccine against classical swine fever after a single vaccination

The period during which pigs are protected after vaccination is important for the successful usage of a marker vaccine against classical swine fever virus (CSFV) in an eradication programme. In four animal experiments with different vaccination-challenge intervals we determined the duration of protection of an E2 subunit marker vaccine in pigs after a single vaccination. Unvaccinated pigs were included in each group to detect transmission of the challenge virus.Three groups of six pigs were vaccinated once and subsequently inoculated with the virulent CSFV strain Brescia after a vaccination-challenge interval of 3, 51/2, 6 or 13 months. All vaccinated pigs, 16 out of 18, with neutralising antibodies against CSFV at the moment of challenge, 3, 51/2, 6 or 13 months later, survived, whereas unvaccinated control pigs died from acute CSF or were killed being moribund. A proportion of the vaccinated pigs did however develop fever or cytopenia after challenge and two vaccinated pigs were viremic after challenge. Virus transmission of vaccinated and challenged pigs to unvaccinated sentinel pigs did not occur in groups of pigs which were challenged 3 or 6 months after a single vaccination. Two out of eight vaccinated pigs that were found negative for CSFV neutralising antibody at 13 months after vaccination died after subsequent challenge.The findings in this study demonstrate that pigs can be protected against a lethal challenge of CSFV for up to 13 months after a single vaccination with an E2 subunit marker vaccine.     

Antibody response of pigs to inactivated monovalent and bivalent vaccines for porcine parvovirus and pseudorabies virus

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.     

兔出血症-巴氏杆菌病二联灭活苗的研制

筛选出了具有良好免疫原性的兔瘟强毒株GMH881和兔巴氏杆菌C51-17株,研制出了兔出血症-巴氏杆菌二联灭活苗,对疫苗进行了免疫剂量、免疫产生期、兔出血症抗体测定、免疫保护期、保存期等试验：确定出二联苗免疫剂量1.0 mL;二联苗在免疫后5 d对兔病毒性出血症强毒的保护率达到100%,二联苗免疫后7d对兔巴氏杆菌的保护率均达到80%以上;二联苗的兔病毒性出血症抗体测定,结果表明,二联苗免疫家兔后7d HI抗体均可达22.75,15 d明显上升,二联苗HI效价30 d达到最高峰,可达28.0,二联苗在60~120 d均可维持在27.0~25.5水平,到180 d时抗体水平面略有下降为25.25,二联苗分别在免疫后4个月、6个月用兔出血症强毒攻击均产生100%保护,在6个月用2个MLD的兔巴氏杆菌攻击保护率可达70%以上,二联苗4~8℃条件下保存期暂定为1年,25℃条件下暂定为半年。     

Risk factors for equine influenza serum antibody titres in young thoroughbred racehorses given an inactivated vaccine

Young Thoroughbred racehorses (222 yearlings entering training and 246 2-year-old horses already in training) from eight flat-training yards in Newmarket, UK were used to monitor serological responses to vaccination with an inactivated influenza virus vaccine. Blood samples taken prior to and after vaccination were tested by single radial haemolysis (SRH) to determine antibody titres (expressed as area of haemolysis in mm(2)). Prior to vaccination, yearlings had mean antibody titres (64+/-4 mm(2)) that were approximately half of those of 2-year-olds (115+/-3 mm(2)) and 89% of yearlings and 73% of 2-year-olds had SRH titres <140 mm(2). Extrapolation from experimental and field studies suggests that these levels would not protect against homologous influenza virus infection. Both age-groups showed anamnestic responses to vaccination resulting in similar peak mean titres ( approximately 160+/-2mm(2)) with 67% of yearlings and 73% of 2-year-olds achieving levels > or =140 mm(2). A second dose of vaccine administered a month after the first in yearlings did not increase the mean titre but 75% of horses had levels of antibody > or =140 mm(2). The vaccination history in the official passport of yearlings showed that 23% had no record of previous vaccination and were probably fully susceptible to infection. For yearlings entering training, the important predictors from multiple-regression analyses of SRH titres prior to vaccination were "Time since last vaccination," "Total number of previous vaccines" and "Age at first vaccination." In 2-year-olds and following two doses of vaccine in yearlings, there was no significant relationship between these factors and SRH titre.     

Evaluation of a recombinant human adenovirus-5 vaccine administered via needle-free device and intramuscular injection for vaccination of pigs against swine influenza virus

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.     

Efficacy of swine influenza A virus vaccines against an H3N2 virus variant

We compared the efficacy of 3 commercial vaccines against swine influenza A virus (SIV) and an experimental homologous vaccine in young pigs that were subsequently challenged with a variant H3N2 SIV, A/Swine/Colorado/00294/2004, selected from a repository of serologically and genetically characterized H3N2 SIV isolates obtained from recent cases of swine respiratory disease. The experimental vaccine was prepared from the challenge virus. Four groups of 8 pigs each were vaccinated intramuscularly at both 4 and 6 wk of age with commercial or homologous vaccine. Two weeks after the 2nd vaccination, those 32 pigs and 8 nonvaccinated pigs were inoculated with the challenge virus by the deep intranasal route. Another 4 pigs served as nonvaccinated, nonchallenged controls. The serum antibody responses differed markedly between groups. After the 1st vaccination, the recipients of the homologous vaccine had hemagglutination inhibition (HI) titers of 1:640 to 1:2560 against the challenge (homologous) virus. In contrast, even after 2nd vaccination, the commercial-vaccine recipients had low titers or no detectable antibody against the challenge (heterologous) virus. After the 2nd vaccination, all the groups had high titers of antibody to the reference H3N2 virus A/Swine/Texas/4199-2/98. Vaccination reduced clinical signs and lung lesion scores; however, virus was isolated 1 to 5 d after challenge from the nasal swabs of most of the pigs vaccinated with a commercial product but from none of the pigs vaccinated with the experimental product. The efficacy of the commercial vaccines may need to be improved to provide sufficient protection against emerging H3N2 variants.     

Vaccine-induced T cell-mediated immunity plays a critical role in early protection against pseudorabies virus (suid herpes virus type 1) infection in pigs

The aim of our study was to evaluate the relative importance of antibody and T cell-mediated immunity in protection against pseudorabies virus (suid herpes virus type 1) infection in pigs. We induced different levels of immune responses by using: (1) a modified live vaccine; (2) the same modified live vaccine with an oil-in-water (o/w) adjuvant; (3) an inactivated vaccine; and (4) the same inactivated vaccine with an o/w adjuvant. Subsequently, we challenged pigs with virulent pseudorabies virus (PRV). We demonstrated that best-protected pigs stood out by maintaining strong T cell-mediated immune (CMI) responses after challenge. Of the immune parameters tested, protection against virus shedding was correlated best with the magnitude of the IFN-gamma response of in vitro re-stimulated peripheral blood mononuclear cells (PBMC) with an additional role for PRV-specific IgG2 antibodies. The use of an o/w adjuvant resulted in higher antibody and CMI responses, in particular with an increased frequency of memory T helper blast cells of in vitro re-stimulated PBMC. However, this adjuvant-induced enhancement of the immune response had a limited additional effect on the efficacy of inactivated vaccines. This study suggests a major contribution of the CMI response in early protection against PRV infection and that PRV-induced IFN-gamma responses may serve as a suitable indicator for assessing the immune status of vaccinated pigs.     

Vaccines against Aujeszky's disease: evaluation of their efficacy under standardized laboratory conditions

A standardized test was developed to compare the efficacy of Aujeszky's disease virus (ADV) vaccines under laboratory conditions. Per test 3 groups of 6 to 8 sero-negative pigs were used. The first vaccination was done at 10 weeks of age. One group was vaccinated once, another was vaccinated twice and the 3rd served as control. Pigs were challenge exposed to the virulent NIA-3 strain of ADV 12 weeks after the first vaccination. Apart from mortality, average periods of growth arrest, fever and virus shedding after challenge were used as parameters to evaluate vaccine efficacy. Two inactivated and 4 attenuated vaccines were tested. Two attenuated vaccine viruses were excreted after vaccination. Despite maximal standardization, a considerable variation still existed between the experiments in mortality and growth arrest periods of control pigs after challenge. However, the controls were always more severely affected than the vaccinated pigs. All vaccines except one were effective in preventing death after challenge, but none conferred complete protection. Most vaccinated pigs still lost weight, developed fever and shed virus after challenge. Revaccination after 3 or 4 weeks had little effect, particularly with the attenuated vaccines. The results of the present study indicate that 2 of the attenuated vaccines conferred the best protection, 1 attenuated vaccine appeared to be as effective as the 2 inactivated ones, and the 4th attenuated vaccine was least effective.     

Stimulation of serum antibody formation in pigs by oral, subcutaneous or combined administration of live porcine rotaviruses or intramuscular inoculation of inactivated porcine rotaviruses in an oil adjuvant]

Only live vaccines prepared from attenuated strains have been used for the specific prophylaxis of rotavirus infections in pigs. These vaccines are administered to sows per os or parenterally to increase the content of antibodies in the blood serum, colostrum and milk, and in this way to provide for the better passive protection of suckling piglets through the maternal antibodies, or to induce the active immunity by pig vaccination. The data on the efficiency of live vaccines administered in both ways differ as to their ability to stimulate significantly increases in the actual levels of antibodies in sows and also as to the possibility of inducing the protection of vaccinated pigs from virulent virus infection. The objective of our trials was to compare the intensity of antibody response evoked by pig vaccination with live virus if the virus was implanted in different ways, and by vaccination with inactivated virus emulsified in oil adjuvant. The live vaccine consisted of a suspension of porcine rotavirus, strain OSU/6, cultivated in MA-104 culture medium with the content of 10(7) TKID50.ml-1, the inactivated vaccine was the identical virus suspension inactivated by an addition of 0.2% formaldehyde during 24 hours at a temperature of 37 degrees C, emulsified in oil adjuvant by means of an ULTRATURAX equipment at a 4:1 ratio.(ABSTRACT TRUNCATED AT 250 WORDS)     

鸭坦布苏病毒病-H9亚型禽流感二联灭活疫苗免疫佐剂筛选

为筛选出理想的鸭TMUV-AIV(H9亚型)二联灭活疫苗免疫佐剂,将灭活的坦布苏病毒液和禽流感病毒(H9亚型)尿囊液分别与白油佐剂、卡波姆佐剂、铝胶佐剂、蜂胶佐剂制成抗原含量相同的TMUV-AIV二联灭活疫苗。应用阻断ELISA方法和血凝抑制方法测定免疫鸭血清中坦布苏病毒和禽流感病毒抗体,比较不同佐剂疫苗对试验鸭的免疫效力。结果表明,以白油作为佐剂的灭活疫苗组免疫效果最好,抗体产生快、抗体水平优于其他各组,免疫2周后60%(6/10)血清样品HI抗体可达1∶8以上,80%血清样品呈TMUV抗体阳性,是制备鸭TMUV-AIV(H9亚型)二联灭活疫苗的理想佐剂。