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1.
A highly purified pilus vaccine prepared from cells of Bacteroides nodosus strain 198 provided a high level of protection against homologous challenge and small, not statistically significant, levels of protection against challenge with 4 other strains each from different serogroups. In a second experiment, a partially purified pilus vaccine from strain 198 induced significant immunity to 1 of 4 heterologous strains which were different from those used in the first experiment. In a third experiment a strain 198 whole cell vaccine produced significant immunity against 3 of 6 heterologous strains used in the first 2 experiments. There was no obvious relationship between the colony type, degree of piliation and level of cross-protection obtained against a particular strain. The results provide further evidence that immunogens associated with, but distinct from, the pilus are involved in cross-protection and that cross-protective antigens are common to some, but not all, strains.  相似文献   

2.
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   

3.
H9亚型禽流感在我国家禽中广泛流行,给养禽业造成巨大经济损失的同时,也严重威胁着公共卫生安全。H9亚型禽流感病毒（avian influenza virus,AIV）具有高度遗传变异性,导致流行株和疫苗株之间抗原匹配性差,从而影响疫苗的临床保护效果,急需研发一种高效、具有交叉保护性的通用型H9亚型禽流感疫苗。马赛克疫苗是针对遗传多样性病原体设计,通过整合所有抗原序列获得一条抗原表位覆盖最广泛的嵌合蛋白,并制备疫苗。本研究参考mosaic疫苗设计原则,设计、优化并合成了一条H9亚型禽流感病毒的mosaic血凝素（hemagglutinin,HA）基因序列,采用反向遗传操作技术,以H1N1亚型流感病毒PR8株为骨架,以mosaic H9HA序列替换PR8株的HA片段,获得重组病毒rPR8-HAm/H9。将其制备为灭活疫苗并免疫SPF雏鸡,监测抗体水平、攻毒保护效果,评价其交叉保护效果。结果表明,重组病毒rPR8-HAm/H9灭活疫苗免疫SPF雏鸡,可诱导机体产生较高水平的HI抗体和中和抗体,可显著抑制攻毒后病毒的脱落,对H9N2 AIV JM0305株的攻毒保护率为80%。rPR8-HAm/H9灭活疫苗可以对异源H9N2 AIV JM0305株产生较好的交叉攻毒保护,为研发基于马赛克技术的禽流感通用疫苗提供了前期基础。  相似文献   

4.
The effects of vaccination of Merino sheep with the purified pili or the whole cells of Bacteroides nodosus strain 198, either in oil or alum-oil adjuvant, on the severity of foot-rot induced with the homologous strain (198) and a heterologous strain (217) were determined in a field experiment, on flood irrigated pasture. The efficacy of the whole cell vaccines was comparable to that of purified pili vaccines, against homologous challenge, when both had a similar content of pilus antigen although the purified pili vaccines induced significantly greater homologous pilus agglutinating antibody titres than the whole cell vaccines. However, against heterologous challenge, the whole cell vaccines in oil (CO) or alum-oil (CAO) provided significantly greater protection than a purified pili-in-oil (PPO) vaccine, the number of severely affected feet in sheep vaccinated with PPO being similar to that of the unvaccinated group. The group vaccinated with purified pili in alum-oil (PPAO) was intermediate between these two extremes. The superior performance of the PPAO in comparison to the PPO vaccine, against heterologous challenge, was associated with significantly higher mean ELISA titres to the outer membrane complex. Western blot analyses implicated a role in cross-protection for outer membrane proteins, in particular a protein Mr 78,000. The PPO vaccine produced fewer, smaller and less persistent vaccination reactions at the inoculation sites than did the other vaccines. Bodyweight gains in the period prior to challenge were much lower for the groups vaccinated with CO and CAO than for the controls and those vaccinated with purified pili, due presumably to the larger vaccination reactions.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
In order to evaluate the protection conferred by an experimental inactivated vaccine against infectious coryza, three challenge trials were undertaken using 112 1-day-old broilers. The vaccine "Hepa Inmuno NC" included bacterial antigens of Avibacterium paragallinarum (serogroups A, B, variant B, and C) as well as antigens of Newcastle virus and hepatitis virus. Fifty-six broiler chicks were vaccinated at the first day of life at the hatchery while another 56 chicks were left unvaccinated. Three infection trials were conducted simultaneously using each of the three serogroups A, B, or C of Av. paragallinarum. In each trial, 17 vaccinated and 17 unvaccinated broilers were used. Challenge was performed at day 31 of life by injection, into the left infraorbital sinus, of approximately 1 x 10(5) colony forming units of the corresponding Av. paragallinarum strain. Clinical signs were recorded on day 2 postchallenge. All broilers were euthanatized and both infraorbital sinuses were bacteriologically examined for the presence of Av. paragallinarum on day 5 postchallenge. In comparison with the unvaccinated broilers, the vaccine significantly reduced the number of broilers with clinical signs after challenge with serogroup B, and significantly fewer vaccinated broilers were positive for the presence of Av. paragallinarum after challenge with serogroup C. On the other hand, no significant protection was observed when broilers were challenged with Av. paragallinarum from serogroup A. Despite the high infection rates in vaccinated chicks after an experimental infection with Av. paragallinarum, it was possible to reduce colonization of Av. paragallinarum (serogroup B) and clinical signs (serogroup C) in broiler chicks by vaccination at the first day of life. Further cross-protection trials should be done, including other Av. paragallinarum strains in the vaccine, especially those from serogroup A.  相似文献   

6.
Due to serotype variations among different avian infectious bronchitis viruses isolated in Tunisia since 2000, protection of chicks, especially broiler flocks, with Mass H120 vaccine often fails. Therefore, association of CR88 (793B type) with H120 vaccines was used for better response. Challenge experiments were then conducted to evaluate tracheal and renal cross-protection in chickens immunized via nasal and eye drops. Conferred protection was measured by clinical signs and macroscopic lesions observed, based on scores attributed according to their severities. The results showed a low protection conferred by H120 alone, as vaccination did not reduce tracheal and kidney lesions (70% scored as 3) after TN20/00 virus challenge, which also led to 10% mortality. Conversely, the challenge results indicated that the combination of the 2 strains (H120/CR88) allow high protection. Based on the results of the challenge experiments, a vaccination protocol coupling CR88 to H120 was applied for industrial broiler flocks. Clinical observations and serological results confirmed that association of heterologous serotypes (H120 and CR88 vaccines) increased the levels of protection against infectious bronchitis viruses compared with the H120 vaccine given alone.  相似文献   

7.
The protective effect of 2 Moraxella bovis pili vaccines against infectious bovine keratoconjunctivitis (IBK) experimentally induced by homologous or heterologous strain challenge with virulent, haemolytic M. bovis strain, Dal 2d, was measured in trials using weaned calves aged 3 to 7 months. Purified pili vaccines were prepared from haemolytic strain Dal 2d, (pilus serogroup IV), and haemolytic strain Epp 63, (pilus serogroup III). Calves were challenged by conjunctival instillation of 1 x 10(9) colony forming units of virulent M. bovis strain Dal 2d 14 days after the second of 2 subcutaneous doses of vaccine. Each consisted of 200 micrograms of pili in alum-oil adjuvant administered at an interval of 21 days. In trial 1 the level of protection against challenge with the homologous strain was 46.7% (p less than 0.01). Small, rapidly resolving lesions of IBK occurred in some vaccinates compared with a larger proportion of severe lesions that required treatment in non-vaccinated calves (p less than 0.025). In trial 2, the level of protection against IBK after exposure of vaccinates to the homologous Dal 2d strain was 72.7%, but no significant level of protection or reduction in the size and duration of lesions was apparent in similarly challenged calves vaccinated with Epp 63 pili when contrasted with susceptible, non-vaccinated controls. No marked reduction in the duration of infection with M. bovis Dal 2d following challenge resulted from vaccination with pili of either of the serogroups III or IV. Rising homologous serum IgG antibody titres to serogroups III and IV pili were recorded in response to vaccination with each antigen.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

8.
To investigate the level of cross-protection induced by equine influenza H3N8 vaccines derived from different lineages, two studies have been carried out with ponies vaccinated with 'American-like' and 'European-like' vaccines and experimentally challenged with a European-like strain. The results demonstrated that equine influenza vaccines clearly protect against challenge with homologous virus if serum antibody titres are sufficiently high. On the other hand, protection is incomplete even when animals vaccinated with heterologous strains have comparative antibody levels. Nevertheless, the protection afforded by heterologous viruses can be improved by stimulating high levels of antibody. It would be advisable to update equine influenza vaccine strains regularly so that they contain similar strains to variants that are circulating in the field.  相似文献   

9.
Pregnant gilts were vaccinated orally with Escherichia coli that produced pilus antigens K99 or 987P. The vaccines were live or dead enterotoxigenic E coli (ETEC) or a liver rough non-ETEC strain which has little ability to colonize pig intestine. Pigs born to the gilts were challenge exposed orally with K99+ or 987P+ ETEC, which did not produce heat-labile enterotoxin or flagella and which produced somatic and capsular antigens different from those of the vaccine strains. Control gilts had low titers of serum and colostral antibodies against pilus antigens, and their suckling pigs frequently had fatal diarrhea after challenge exposure. Serum antibody titers against pilus antigens of the vaccine strains increased in the gilts after vaccination with liver ETEC, and the colostral antibody titers of these gilts were higher than those of controls. Pigs suckling such vaccinated gilts were more resistant than controls to challenge strains were of different pilus types, and it could not be attributed to enterotoxin neutralization by colostrum. In contrast to the live ETEC vaccines given to the pregnant gilts, the liver rough non-ETEC and dead ETEC vaccines stimulated little or no production of antibody against pilu, and the pigs born of these vaccinated gilts remained highly susceptible to challenge exposure. The results support the hypothesis that pilu can be protective antigens in oral ETEC vaccines. It was indicated that in the system reported, protection depended on living bacteria for the production of pilus antigens in vivo or for the transport of pilus antigens across intestinal epithelium.  相似文献   

10.
Bovine viral diarrhea virus (BVDV) has various economic impacts associated with diarrhea, poor performance, an increase in the frequency of other infections and lethal outcomes. Both genotypes, namely BVDV-1 and BVDV-2, as well as different subgroups within these genotypes have been reported worldwide. Understanding the serological differences among the BVDV subgroups is important for disease epidemiology and prevention as well as vaccination programs. The aim of this study was to determine the serological relatedness among the subgroups in BVDV-1. For that purpose, sheep hyperimmune sera were collected against representative strains from 6 of the subgroups of BVDV-1 (BVDV-1a, -1b, -1d, -1f, -1h and -1l). The serum samples that gave the peak antibody titer to the homologous strains were used to perform cross neutralization assays. The highest homologous antibody titer (1:5160) was obtained against BVDV-1h. Regarding the cross neutralizing (heterologous) antibodies, the lowest titer (1:20) was produced by the BVDV-1f antiserum against the BVDV-1a and BVDV1-b viruses. The highest cross neutralizing titer (1:2580) achieved by the BVDV-1h antiserum was against the BVDV-1b strain. The cross neutralization results indicated particular serological differences between the recently described subgroup (BVDV-1l) and BVDV-1a/-1b, which are widely used in commercial vaccines. Considering the cross neutralization titers, it is concluded that selected BVDV-1l and BVDV-1h strains can be used for the development of diagnostic and control tools.  相似文献   

11.
H9亚型禽流感病毒流行毒株交叉免疫攻毒保护试验   总被引：3，自引：0，他引：3  
采用1998-2009年在河北、河南及山东分离的3株禽流感H9亚型流行毒株,分别制备灭活疫苗,免疫SPF鸡,免疫后21 d,采血测定HI抗体,然后用从上述3个地区及北京分离的共5株禽流感H9亚型流行毒株进行攻击,观察不同时期及地点分离的H9亚型流行毒株的交叉免疫攻毒保护效果。结果显示,用不同时期及地点的3个分离毒株所制备出的灭活疫苗免疫鸡后,各免疫组试验鸡H9亚型禽流感的HI抗体效价均明显上升,不同毒株灭活疫苗所诱导产生的HI抗体效价存在着不同程度的差异,用同源毒株作为抗原测定免疫组鸡的血清样品,可获得较高的HI抗体效价。攻毒试验结果证明,对不同时期及地点分离的禽流感H9亚型流行毒株间产生了较好的交叉保护力。用1998年分离的WD98株制备出的灭活疫苗对目前的流行毒株仍具有较好的保护效力。  相似文献   

12.
Three groups of ten calves were each immunised with a total of 400 micrograms pili prepared from three separate strains of Moraxella bovis in Alhydrogel-oil adjuvant as two divided, equal doses 21 days apart. Groups 1 and 2 each received a monovalent vaccine made from strain 4L and S276R respectively, which belonged to pili serogroup A. Group 3 received vaccine made from pili of strain Maff1, belonging to serogroup F. A further group of ten calves served as non-vaccinated controls. Calves in groups 1 and 2 had developed serogroup A-specific antibody and those in group 3 developed serogroup F-specific antibody, and some evidence of cross-reacting antibody was also detected when measured by an agglutination test using formalin-killed piliated cells of serogroup A strain 4L. Although antibody titres measured against purified pili by ELISA were highest with homologous serogroup antigens, cross-reactive titres to shared epitopes of M. bovis pili were also detected by this method. Ocular challenge of the 40 calves with virulent M. bovis of serogroup A strain S276R was carried out 14 days after the second vaccine dose. All non-vaccinated calves developed infectious bovine keratoconjunctivitis (IBK). The percentage protection in groups 1 (strain 4L) and 2 (strain S276R) was 60% and 80% respectively (P less than 0.05), with mean lesion scores of 0.7 and 0.3 out of a possible 6.0. The percentage protection of calves in group 3 (strain Maff1) was only 30%, with a mean lesion score of 1.4 compared with 2.2 for non-vaccinated controls. The present findings, together with other evidence indicating that immunity to IBK is serogroup-specific, suggest that inclusion of pili from one representative strain from each of the seven Australian and British serogroups in a polyvalent, subunit vaccine should effectively protect the majority of cattle against IBK caused by most field strains of M. bovis encountered in Australia and the United Kingdom.  相似文献   

13.
One-day-old chicks with maternally derived antibodies were vaccinated against infectious bronchitis (IB) with 3000 EID50 of the IB vaccine virus designated H120. The degree of protection induced by intranasal-eye drop (IE) vaccination was compared to that achieved by spray (S) vaccination. The protection afforded by vaccination was monitored by intratracheal challenge with IBV strain M-41 (clinical signs, ciliary activity in tracheal explants, virus isolation) and by serological tests (ovoneutralization, microneutralization in cell culture, haemagglutination inhibition (HI) test, ELISA). Intranasal-eye drop vaccination provided protection against intratracheal challenge. Immunity developed around 31 days of age. Spray vaccination failed to give protection against challenge by the same route. No difference was demonstrable in effectiveness between the two routes of vaccination by serological tests. No elevation of the antibody level occurred in either group. The level of maternally derived antibodies declined with age.  相似文献   

14.
本研究拟评估仔猪接种猪繁殖与呼吸综合征减毒活疫苗对猪圆环病毒病疫苗、猪瘟疫苗免疫的干扰情况,并分析不同免疫方式对仔猪生长性能的影响,以期为探究PRRSV减毒活疫苗与PCV2、CSF疫苗的联合免疫提供数据参考。本研究先以100头仔猪为研究对象,将其随机分为A、B、C、D 4组。其中A组仔猪免疫PRRSV减毒活疫苗7 d后免疫PCV2疫苗;B组仔猪同期分点注射PRRSV减毒活疫苗和PCV2疫苗;C组仔猪仅免疫PCV2疫苗;D组仔猪仅免疫PRRSV减毒活疫苗。另外再筛选100头仔猪,随机分为E、F、G、H 4组。E组仔猪于免疫PRRSV减毒活疫苗12 d后免疫CSF疫苗;F组仔猪同期分点注射PRRSV减毒活疫苗和CSF疫苗;G组仔猪仅免疫CSF疫苗;H组仔猪仅免疫PRRSV减毒活疫苗。免疫4周后,测定仔猪血清中相关抗体水平。同时,称量免疫前后各组仔猪的体重,计算不同免疫方案仔猪的平均日增重。结果表明：A~D组中, A组和B组仔猪在免疫4周后均产生了较高水平的PRRSV及PCV2抗体,且A组抗体水平略高于B组。C组仔猪仅产生了PCV2抗体,D组仔猪产生了较高水平的PRRSV抗体。E~H 4组中,E组和F组仔猪均产生了较高水平的PRRSV及CSFV抗体。G组仔猪仅产生了高水平的CSFV抗体,H组仔猪仅产生了高水平的PRRSV抗体。A、B、C、D 4组中B组仔猪的平均日增重最高;而E、F、G、H 4组中E组仔猪的平均日增重显著高于其他3组。PRRSV减毒活疫苗与PCV2疫苗或CSF疫苗同期分点免疫、免疫PRRSV减毒活疫苗一段时间后再免疫PCV2或CSF疫苗均能诱导仔猪产生高水平的抗体;在体液免疫方面,PRRSV减毒活疫苗免疫与否均未对另外二种疫苗表现出明显的干扰作用。在仔猪28日龄时同期分点免疫PRRSV减毒活疫苗与PCV2疫苗,12 d后再免疫CSF疫苗的免疫方案不仅能诱导仔猪产生高水平抗体,还可以使仔猪具备较高的平均日增重。  相似文献   

15.
In the detection of antibodies against exogenous subgroup A avian leukosis viruses (ALVs) using a representative subgroup A virus, concordance between enzyme-linked immunosorbent assays (ELISAs) and serum neutralizations ranged from 83 to 95%. In ELISAs, subgroup A- and subgroup B-specific neutralizing antisera were equally reactive against ALVs of subgroups A, B, and E. Conversely, little cross-reactivity of high-titered subgroup E antisera was observed against subgroup A viruses. Significant cross-reactivities of spontaneously induced subgroup E-neutralizing antisera were observed when tested against a representative subgroup B ALV. Because some normal chickens spontaneously mount antibodies against infectious endogenous viruses, misleading results may be obtained if subgroup B or E ALVs are the source of target antigens in ELISAs.  相似文献   

16.
SUMMARY A multivalent footrot vaccine has been developed, containing pilus antigens produced in recombinant Pseudomonas aeruginosa and representing all nine serogroups of Dichelobacter (Bacteroides) nodosus commonly recognised in the field. The responses of sheep to the multivalent vaccine have been compared with those to monovalent vaccines representing only a single serogroup. Antigenie competition between serogroups occurred in sheep immunised with the multivalent formulation, but high levels of protection were still achieved. The study showed that in multivalent footrot vaccines, antigenic competition is predominantly due to the presence of a family of immunologically-related pilus antigens rather than to interference by extraneous proteins.  相似文献   

17.
The consequence of cryptosporidiosis on the immune response of vaccinated chickens against Newcastle disease and/or avian influenza was studied by using 240, 1 day old, male, white Hy-Line chicks and divided into 8 groups and subgroups. Each group or subgroup was consisting of 30 chicks (15?×?2 replicates). The first and second groups were kept as unvaccinated control, G1uninfected and G2 infected. G3, G4 and G5 contained 2 subgroups A&B (G3A, G3B, G4A, G4B, G5A and G5B). Chicks of subgroup A were vaccinated only while chicks of subgroup B were infected and vaccinated. These chicks were orally inoculated with 5?×?105 oocysts of Cryptosporidium baileyi (C. baileyi) at 2 days of age. Chickens were vaccinated intraocular with live Newcastle disease (ND) vaccine (Hitchner on day 7th and LaSota on day 17th of chicken life) (G3) or vaccinated by subcutaneous route with Volvac®- H5N2- AI vaccine on day 10 of chicken life (G4). Last group (G5) was infected similarly and vaccinated with ND and AI vaccines with the same day, dose and route of vaccination for each one. Random blood samples were collected for 3 weeks post-vaccination for investigation of humoral immune response against Newcastle and/or avian influenza vaccines by the haemagglutination inhibition (HI) test. The results showed that H5N2 vaccine at day 10 of chicken life is effective in chickens indicated by the geometric mean of HI titer against AI virus. The findings of this study showed that the infection with Cryptosporidia in the broiler chicken has a depressive effect on the immune status of the birds vaccinated against ND and/or AI vaccination. Moreover, the obtained protection rates against challenge with virulent ND virus observed to be parallel to the results of HI- test. Also, by using 2 different antigens (one commercial and field prepared antigen) to avian influenza virus, lower Geometric mean (GM) HI titer were appeared in infected and vaccinated group than vaccinated group only. A study of the relative lymphoid organs weight such as bursa of Fabricius from the experimental chicks indicated that those organs were comparable between the groups infected-vaccinated and vaccinated only. Non significant variations in final live weight between uninfected control and infected groups were indicated. Also, H5N2-AI vaccination at 10 days old did not affect the final live weight. ND and/or AI Vaccination could not be a substitute to application of good hygienic measures and fecal examination of the birds especially for protozoal diseases such as cryptosporidiosis. It could be concluded that cryptosporidiosis could be one cause of ND and/or AI vaccination failure in poultry farms.  相似文献   

18.
应用电镜技术、血清学检查、生物学试验等方法,从未注射过疫苗的某自然发病鸡群分离出一株新城疫病毒。该分离株对１０日龄鸡胚的平均致死时间为１１６小时,静脉接种致病指数为０．０６,其毒力介于新城疫病毒的ＬａＳｏｔａ株与Ｖ４株之间。免疫原性试验结果表明,该分离株具有免疫后无不良反应、免疫后６天开始产生抗体、产生的抗体效价高、对新城疫强毒的攻击能１００％保护等特点,是一株良好的新城疫候选疫苗株  相似文献   

19.
Whereas H5N1 vaccine and several H5N2 vaccines are commercially available and are used to control H5N1 outbreaks in some endemic countries, infections hit many vaccinated flocks. The following study was conducted to compare the efficacy of such vaccines and to assess their potential induction of antibodies against the haemagglutinin of local H5N1 isolate after single vaccination. The possible beneficiary effect of booster dose at different intervals was screened for both H5N1 vaccine as well as a selected H5N2 candidate. Differences in the serological immune response among native and cross breeds were also screened. No significant variations were detected between available commercial H5N1 and H5N2 vaccines after single vaccination. Two vaccination shots using H5N1 but not H5N2 vaccine were found to be superior to a single vaccination scheme, where chicks developed more conceivable antibody titers than in single vaccination program. There was considerable variation among chicken lines in the immune response to H5N1 vaccine: native breeds possessed the highest antibody titers as compared to other breeds.  相似文献   

20.
Atrophic rhinitis (AR) is a widespread and economically important disease of swine caused by Bordetella bronchiseptica and Pasteurella multocida. It can be controlled by vaccination. This study investigates the effect of altering the composition (adjuvants and/or addition of formalin-inactivated P. multocida toxin, fPMT) of conventional vaccines on the serological profile and on protection against AR in swine. A significantly higher B. bronchiseptica specific antibody titre was detected for vaccines with novel immunostimulants, the best being Montanide IMS 1313 (1:630 compared to 1:274 obtained with alum). The highest B. bronchiseptica antibody titre was demonstrated for a combination of B. bronchiseptica--fPMT, while PMT antibody titre was highest for monovalent fPMT (both adjuvanted with IMS 1313). The AR-specific antibodies were transmitted from dams to their offspring in similar titres and with the same hierarchy of effectiveness. After a B. bronchiseptica--P. multocida bacterial challenge, piglets from dams vaccinated with fPMT combined with B. bronchiseptica or B. bronchiseptica--P. multocida bacterins showed the lowest nasal lesions scores (4.5 and 3.2, respectively, out of a possible maximum score of 18). These combinations, both of which were adjuvanted with IMS 1313, gave the best protection against experimentally induced AR. Our results show that the adjuvant and the antigen composition of the vaccine strongly affect seroconversion, and that the AR-specific antibody titre does not necessarily correlate with the degree of protection.  相似文献   

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