首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
OBJECTIVE: To evaluate the ability of commercially available Escherichia coli J5 bacterin to protect rabbits from experimental challenge with Pasteurella multocida. ANIMALS: 40 P multocida-free New Zealand White rabbits. PROCEDURES: Rabbits were assigned to 1 of 4 groups of 10 rabbits each. Three of the groups were inoculated SC with J5 bacterin at 8 weeks old. Inoculation was repeated 3 and 6 weeks later. The fourth group was not inoculated and served as controls. Groups 1, 2, and 3 were given 10(9), 10(8), and 10(7) colony forming units (CFU), respectively. Response was monitored by titer assessment, using an E coli J5 antigen capture ELISA. Five weeks after the last inoculation, all rabbits were challenged with P multocida and observed for an additional 5 weeks. Clinical, hematologic, serologic, culture, and necropsy data were collected. RESULTS: Inoculation of rabbits with 10(9) CFU of E coli J5 bacterin-induced titers that were significantly greater than titers of rabbits vaccinated with 10(8) or 10(7) CFU or those in controls. The incidence of acute bacteremia was lower in rabbits with high titers. At necropsy, prevalence of lesions typical of P multocida was not significantly different among groups. Prevalence of histologic lesions was also not significantly different among groups. CONCLUSIONS AND CLINICAL RELEVANCE: Although the bacterin induced considerable antibody response and possibly reduced the rate of bacteremia, antibodies were not protective against long-term colonization or infection of the frontal sinuses or tympanic bullae by the challenge strain of P multocida. This bacterin in its currently available form is unlikely to aid in reducing the prevalence of pasteurellosis in rabbits.  相似文献   

2.
Turkeys given cell-free culture filtrate (CCF) of Pasteurella multocida strain R44/6 orally, via air sacs, or subcutaneously mixed 1:1 with incomplete Freund's adjuvant (IFA) at 6 and 9.5 weeks of age were compared with negative controls given bacteriologic medium and positive controls vaccinated with a commercial bacterin. At 13 weeks of age, serum antibody titers to P. multocida were detectable only in turkeys given CCF in IFA (low titers) and positive control turkeys (high titers), at which time turkeys were challenged orally with either the homologous strain or strain P-1059. Protection against challenge with strain R44/6 was provided by the commercial bacterin, CCF in IFA, and CCF given via air sacs. When turkeys were challenged with strain P-1059, protection was superior in turkeys given CCF via air sacs, intermediate in turkeys given commercial bacterin or CCF in IFA, and absent in negative control turkeys and turkeys given CCF orally. These results indicate CCF is an effective immunogen when administered via the lower respiratory tract for protecting turkeys against pasteurellosis.  相似文献   

3.
OBJECTIVE: To determine the seroprevalence of antibodies to gram-negative core antigens (GNCA) in specific-pathogen-free (SPF) rabbits (ie, free of Pasteurella multocida) and rabbits of undefined bacterial status (conventional). SAMPLE POPULATION: Serum samples were obtained from 7 groups of rabbits. The SPF rabbits comprised 2 adult groups and 1 immature group, whereas the 4 groups of conventional rabbits were all adults. PROCEDURE: A seroprevalence survey was conducted on rabbit sera for antibodies against GNCA, using an Escherichia coli J5 antigen-capture ELISA. RESULTS: Collective geometric mean titer (GMT) of adult rabbits was 1:6,463. The GMT of each of the 6 groups of adult rabbits was 1:956, 1:1,133, 1:4,525, 1:5,338, 1:7,669, and 1:25,600. Titers of populations differed significantly. CONCLUSION: Data analysis revealed there were anti-GNCA antibodies in rabbits. Similar to other species, the prevalence of IgM and IgG anti-GNCA antibodies increased with age. The IgG response was more marked than the IgM response. The SPF rabbits had lower IgG anti-GNCA titers than conventional rabbits, indicating possible cross-reactive epitopes between P multocida and Enterobacteriaceae. Rabbits with the highest anti-GNCA titers were those used in polyclonal antibody production, possibly stemming from endotoxin contamination of antigen or adjuvant. CLINICAL RELEVANCE: The possible cross-reactive antibodies directed at homologous wall components of Pasteurellaceae and Enterobacteriaceae could prove to be a possible heterotypic vaccination strategy for the protection of rabbits against pasteurellosis. Investigators should determine whether antigen impurity (endotoxin contamination) influences epitope focus during polyclonal antibody production and whether it affects sera variability among rabbits.  相似文献   

4.
The probability of survival of chickens following a challenge dose of the X-73 strain of Pasteurella multocida was calculated based on enzyme-linked immunosorbent assay (ELISA) titer. Chickens were vaccinated subcutaneously with the Clemson University strain of P. multocida. On days 3, 5, 7, 10, 12, 14, 21, and 28 post-vaccination, 10 vaccinated chickens and 5 unvaccinated controls were selected at random, bled, and then challenged with 2000 colony-forming units of X-73. The ELISA titers to P. multocida vaccination and responses to challenge were recorded. A logistic procedure predicted probability of survival related to ELISA titer. The ELISA titer and survival were highly correlated. A flock profile for each day of challenge was developed based on a probability of survival (PS) at the following levels: PS less than 25%, 25% less than or equal to PS less than 50%, 50% less than or equal to PS less than 75%, and PS greater than or equal to 75%. The antibody response of the chickens through 28 days post-vaccination demonstrated a classic response to vaccination.  相似文献   

5.
Cell-free culture filtrate (CCF) of Pasteurella multocida strain R44/6 (serotype 3/4/9/12) was fractionated by ultrafiltration into fractions of less than 10,000, greater than 10,000, greater than 30,000, and 10,000 to 30,000 molecular weight (MW). The less-than-10,000-MW fraction contained little endotoxin comparable to bacteriologic medium; the 10,000-to-30,000-MW fraction had a moderate amount of endotoxin, whereas the greater-than-10,000- and greater-than-30,000-MW fractions contained high levels of endotoxin. Following ultrafiltration, each fraction, except the less-than-10,000-MW fraction, was divided into two equal parts, and endotoxin was removed from one part. Turkeys were vaccinated with the various MW fractions of CCF, with and without endotoxin, via the air sacs at 6 and 9 weeks of age and compared with negative controls given bacteriologic medium and positive controls vaccinated with a commercial bacterin. Before oral challenge with strain P-1059 (serotype 3) at 12 weeks of age, antibody titers were detected only in positive control turkeys. Protection against challenge, as measured by post-challenge mortality and body-weight gain, was provided by the greater-than-10,000-, greater-than-30,000-, and 10,000-to-30,000-MW fractions containing endotoxin and the commercial bacterin. Turkeys that had been vaccinated with bacteriologic medium and the four different fractions without endotoxin were not protected. Results indicated that endotoxin in CCF of P. multocida is critical in protecting turkeys from pasteurellosis.  相似文献   

6.
OBJECTIVE: To determine efficacy of intranasal vaccination of rabbits with Pasteurella multocida A:3 outer membrane proteins (OMP) expressing iron-regulated OMP (IROMP) in conferring protection against experimental challenge exposure. ANIMALS: 52 male New Zealand White rabbits. PROCEDURE: Rabbits were vaccinated intranasally on days 0, 7, and 14; some vaccines included cholera toxin (CT) as an adjuvant. Concentrations of intranasal IgA and serum IgG antibodies against P multocida OMP were determined. In experiment A, rabbits were vaccinated with either phospate-buffered saline solution (PBSS), PBSS-CT, OMP-CT, or IROMP-CT, challenge-exposed intranasally on day 16, and euthanatized and necropsied on day 28. Rabbits were also vaccinated with OMP or IROMP without CT and were not challenge-exposed. In experiment B, rabbits were vaccinated with PBSS, PBSS-CT, IROMP, or IROMP-CT. On day 17, rabbits were challenge-exposed intranasally. Nasal bacteria and antibodies were determined on day 24. RESULTS: In experiment A, OMP-CT vaccination stimulated mucosal and systemic antibody responses to the bacterium and enhanced resistance against challenge exposure. Intranasal bacterial counts were not significantly reduced. Vaccination with IROMP-CT stimulated mucosal and systemic antibodies, enhanced resistance to challenge exposure, and significantly reduced nasal bacterial counts. In experiment B, natural infection was detected in several rabbits at challenge exposure; however, IROMP-CT-vaccinated rabbits had significantly higher serum and nasal antibody responses, compared with other rabbits IROMP-CT-vaccinated rabbits had significantly lower nasal bacterial counts compared to control rabbits. CONCLUSIONS AND CLINICAL RELEVANCE: Intranasal vaccination of rabbits with P multocida outer membranes containing IROMP and CT stimulated immunity against experimental pneumonic pasteurellosis.  相似文献   

7.
Colostrum-deprived lambs were vaccinated IM with 10 mg (dry weight) of Corynebacterium pseudotuberculosis whole cells (WC) or cell walls (CW) and their immunity was challenged by IV injection of 3.1 X 10(4) colony-forming units of C pseudotuberculosis. Before challenge exposure, the logarithmic mean antibody titers were 2.0837 in lambs that were vaccinated with WC, 2.6858 in lambs that were vaccinated with CW, and 1.4214 in control lambs. Significant protection was demonstrated by fewer abscesses and organisms in the lungs of lambs vaccinated with WC or CW (P less than 0.05) than in control lambs. By the same criteria, more protection was provided to lambs vaccinated with CW than to lambs vaccinated with WC.  相似文献   

8.
Fourteen Pasteurella multocida-free rabbits were inoculated intranasally with a streptomycin-dependent mutant of P. multocida serotype 12:A. Vaccinations with approximately 10(8) colony forming units were done on days 0, 14 and 28. Two weeks later the animals were separated into groups, which included 12 rabbits divided into two control groups of six unvaccinated Pasteurella-free animals. Seven vaccinated rabbits were challenged intranasally with the homologous virulent parent strain and the other seven vaccinates were challenged with a virulent strain of serotype 3:A. Rabbits were necropsied two weeks later. The vaccinated group challenged with the parent strain showed a more rapid nasal clearance of the organism than the vaccinated group challenged with the heterologous strain. However, the number of positive cultures of P. multocida recovered from tissues post-challenge were similar in vaccinated and control animals. In a significant number of animals, vaccination with serotype 12:A induced detectable antibody production to somatic antigens of both 12:A and heterologous strain 3:A.  相似文献   

9.
We evaluated protection conferred by mucosal vaccination with replication-competent adenovirus-free recombinant adenovirus expressing a codon-optimized avian influenza (AI) H5 gene from A/turkey/WI/68 (AdTW68.H5ck). Commercial, layer-type chicken groups were either singly vaccinated ocularly at 5 days of age, singly vaccinated via spray at 5 days of age, or ocularly primed at 5 days and ocularly boosted at 15 days of age. Only chickens primed and boosted via the ocular route developed AI systemic antibodies with maximum hemagglutination inhibition mean titers of 3.9 log2 at 32 days of age. In contrast, single vaccination via the ocular or spray routes maintained an antibody status similar to unvaccinated controls. All chickens (16/16) subjected to ocular priming and boosting with AdTW68.H5ck survived challenge with highly pathogenic AI virus A/chicken/Queretaro/14588-19/95 (H5N2). Single ocular vaccination resulted in 63% (10/16) of birds surviving the challenge followed by a 44% (7/16) survival of single-sprayed vaccinated birds. Birds vaccinated twice via the ocular route also showed significantly lower (P < 0.05) AI virus RNA concentrations in oropharyngeal swabs compared to unvaccinated-challenged controls.  相似文献   

10.
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   

11.
A study was conducted to compare immunogenicity of a Brucella abortus lipopolysaccharide (LPS) and the duration of infection in 5 strains of mice. Mice of strains CBA/NJ, BALB/c, CD-1, C3H/HeN, and C3H/HeJ were allotted into 2 large groups (vaccinated with proteinase K-treated LPS or nonvaccinated) and 6 subgroups based on the intervals between challenge exposure to B abortus strain 2308 and the week the response data were obtained. Criteria used in comparing responses between the various strains of mice as well as between vaccinated and nonvaccinated mice were splenomegaly, colony-forming units (CFU) from spleens, and antibody titers. Responses were evaluated at 1, 2, 3, 5, 8, and 12 weeks after challenge exposure. Results indicated that all strains of mice became infected and maintained infection throughout the 12-week period, the percentages of mice infected were significantly (P less than 0.05) less in vaccinated mice for the first 5 weeks after challenge exposure, and there were no direct correlations between increased immunoglobulins (IgM and IgG titers) and reduction in CFU. Vaccinated mice of strains BALB/c, CD-1, C3H/HeN, and C3H/HeJ had increased titers when challenge exposed and also had significantly (P less than 0.05) smaller spleens and lower CFU. Vaccinated CBA/NJ mice did not have marked antibody titers. The overall results indicated that vaccination with LPS offers some initial protection against B abortus strain 2308 infection, but this protection disappears gradually and in various degrees in the 5 strains of mice studied.  相似文献   

12.
To compare the immune response elicited by 3 routes of vaccination, 36 calves were randomly allotted to 4 groups of 9 calves each. Group I was vaccinated subconjunctivally only. Group II was vaccinated concomitantly, both subconjunctivally and in the dewlap. Group III was vaccinated in the dewlap only. Group IV was not vaccinated and served as a virulence control for the Moraxella bovis culture. Calves in groups I, II, and III were given 2 inoculations with 14 days between inoculations. Twenty-one days after the last inoculation, the ventral conjunctival sac of all calves was instilled with cells of a virulent M bovis strain. After challenge exposure, all vaccinated calves (groups I, II, and III) had evidence of enhanced resistance, compared with the nonvaccinated calves. The highest to lowest gradients of immune responsiveness were: Group I greater than or equal to group II greater than group III greater than group IV. When immune criteria, such as the percentage of diseased eyes, the mean duration of infection, the severity of corneal lesions, and the serologic response were compared, groups I and II were significantly (P less than 0.05) more resistant to challenge exposure than were groups III and IV. Group III was significantly (P less than 0.05) different from group IV in severity of lesions and in serologic response. Also, the mean duration of infection was shorter, and the percentage of diseased eyes was less in group III than in group IV (P greater than 0.10). Group I was more resistant than was group II (P less than 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

13.
Turkey breeder candidates were exposed to attenuated Pasteurella multocida (Clemson University strain) via both mouth (one or three times) and wing-web stick (one or two times). Significant protection lasting to 25-30 weeks post-vaccination was conferred under such immunization programs. The best protection with the fewest adverse effects of vaccination was established when orally vaccinated turkeys were subsequently vaccinated via wing-web at 20 and 25 weeks of age. High doses of attenuated P. multocida via wing-web produced lameness (synovitis and osteomyelitis) and severe wing lesions in growing turkeys.  相似文献   

14.
Vaccination against progressive atrophic rhinitis using a purified recombinant derivative of the Pasteurella multocida toxin (PMT), was carried out. Ten pregnant gilts were vaccinated twice with the nontoxic derivative (dO) which apart from a lack of 121 amino acids had an amino acid sequence identical to PMT, while seven gilts were vaccinated with a purified, formaldehyde treated, native PMT and ten gilts served as non-vaccinated controls. The resulting piglets were inoculated intranasally with Bordetella bronchiseptica and toxigenic P. multocida. Among piglets from the nonvaccinated gilts all except one developed clinical atrophic rhinitis and 90% developed severe turbinate atrophy while only a few pigs in the vaccinated groups developed clinical or pathological signs of disease. Gilt colostra from the two vaccinated groups had similar mean anti-PMT titers and the mean titers in the offspring's sera from these groups were nearly identical throughout the study. No pigs born from unvaccinated gilts were seropositive until 8 wk of age (7 wk post-challenge) but 23% became seropositive at slaughter. The infection rate with toxigenic P. multocida in piglets and the total number of P. multocida colonies cultured from nasal swabs were significantly reduced at 5 wk and 8 wk of age in the vaccinated groups, when compared to controls. There was a significantly improved weight gain (greater than 9%) from birth to slaughter in offspring from vaccinated gilts. No significant differences in feed conversion rate or % lean meat were observed among the groups. The study showed the excellent immunoprotective properties of the nontoxic derivative of the PMT molecule.  相似文献   

15.
Colostrum-deprived lambs and CF1 mice were vaccinated with water-in-oil emulsion vaccines containing nonviable whole cells (WC) of Corynebacterium pseudotuberculosis with and without muramyl dipeptide (MDP). Efficacy of vaccines was determined from the survival of mice and lesions in lambs after IV injection of 10(4) colony-forming units of C pseudotuberculosis. In mice, protection was related to the concentration of WC in the vaccine. At 50, 100, or 150 micrograms of WC, protection was good (78.8%). At 10 or 25 micrograms of WC, protection was considerably less (54.7%). At high WC concentrations, protection could only be moderately increased to 82.3% with high (50 and 100 micrograms) concentrations of MDP or increased to 90% protection with low (5 and 10 micrograms) concentrations of MDP. At low WC concentrations, protection significantly decreased to 32% (P less than 0.025) with high concentrations of MDP, but significantly increased to 72.5% (P less than 0.025) with low concentrations of MDP. Therefore, the amount of protection with lower concentrations of WC and MDP was comparable with the amount of protection with higher concentrations of WC without MDP. In lambs, high prechallenge antibody titers (geometric mean titers from 5.1 to 5.4 by day 35) were observed after vaccination with WC. Protection and vaccination site abscesses in lambs were related to the concentration of WC and MDP. Pulmonary or vaccination site abscesses were not observed in 4 of 4 lambs vaccinated with 1 mg of WC + 50 micrograms of MDP.  相似文献   

16.
In vitro experiments of adhesion and colonisation of mucosal surface fragments (nose, trachea) from freshly killed rabbits with four strains of Pasteurella multocida subsp. multocida with different types of capsule antigen (A, D, without capsule) showed the following results: Above all the capsule serovar A strain, producing a capsule of hyaluronic acid and fimbria, were able to adhere and to form microcolonies on the mucosal surface. Microvilli of epithelial cells and mucus producing cells were recognized as the place of adhesion. The formation of microcolonies occurred with a destruction of the kinocilia, which was caused by a bacteria free culture filtrate as well.  相似文献   

17.
An indirect enzyme-linked immunosorbent assay (ELISA) was developed to measure humoral antibody responses of chickens against Pasteurella multocida. A standard indirect hemagglutination (IHA) test was used to compare serologic results with those of ELISA. The ELISA was also used following challenge with P. multocida to compare the efficacy of three commercial fowl cholera vaccination regimens. Although antibody titers measured by ELISA and IHA were highly correlated, ELISA was at least twice as sensitive as IHA. Antibody measured by ELISA and IHA also correlated significantly with protection against P. multocida challenge. No mortality occurred in any of the three vaccinated challenged groups. However, control unvaccinated chickens experimentally infected with P. multocida developed signs of acute pasteurellosis and died by the 10th day post-challenge. Impression smears made of hepatic tissue from all chickens were stained (Wright's stain), and typical bipolar rods characteristic of Pasteurella were identified in smears from unvaccinated challenged controls only.  相似文献   

18.
Chickens were protected against fowl cholera by ribosomal vaccines prepared from noncapsulated Pasteurella multocida. Passive hemagglutination (PHA) titers to lipopolysaccharide (LPS) and the degree of protection conferred by ribosomal vaccines were diminished or abolished when ribosomes were chromatographed on an immunoadsorbent column. Addition of subimmunogenic amounts of serotype 1 (homologous) LPS to highly purified ribosomes resulted in vaccines that protected against challenge exposure and produced PHA titers to homologous LPS. Addition of serotype 5 LPS to highly purified ribosomes did not protect chickens against challenge exposure with serotype 1 P multocida, but produced PHA titers to serotype 5 LPS. Combinations of serotype 1 ribosomal RNA and serotype 1 (homologous) LPS did not protect chickens or produce PHA titers to LPS. Purified ribosomes from Brucella abortus, Aspergillus fumigatus, and chicken liver were combined with LPS from P multocida and were evaluated as vaccines. Brucella abortus and A fumigatus ribosomes combined with LPS protected chickens as well as did bacterin made from whole cells of P multocida. Chicken liver ribosomes combined with LPS did not provide protection. To determine whether a protein carrier would substitute for ribosomes, methylated bovine albumin (MBA) was combined with LPS and evaluated as a vaccine. A serologic response to LPS was induced by MBA-LPS vaccine, but the vaccine offered no better protection than when LPS was used alone as vaccine. Ribosome-LPS vaccines produced serologic responses to LPS that were at least 5-fold greater than those produced by MBA-LPS vaccine.  相似文献   

19.
Broiler minibreeder hens were vaccinated for protection against fowl cholera at 12 and 21 weeks of age using several vaccination schemes, which included a live Pasteurella multocida (CU strain) vaccine, two commercial polyvalent fowl cholera oil-based bacterins, and two experimentally prepared polyvalent oil-based bacterins. Some treatment groups received only live or killed vaccines, whereas others received a live vaccine at 12 weeks followed by a killed product at 21 weeks. At 42 weeks of age, all birds that received the live CU vaccine twice or once followed by a bacterin survived challenge. Birds that received killed vaccines only were significantly less protected but still showed a respectable survival rate of 86%. All unvaccinated controls died within 72 hr after challenge. At 72 weeks of age, overall protection was lower than that at 42 weeks, regardless of vaccination treatment. Antibody titers were usually higher in birds that received bacterins than in those receiving live vaccines, yet overall protection was still greater in those birds that received the live cholera vaccine twice.  相似文献   

20.
Bovine bacterial respiratory diseases have been one of the most serious problems due to their high mortality and economic loss in calves. The vaccinations of bovine bacterial respiratory vaccines have been complex because of no multivalent vaccine. In this study, novel multivalent bovine bacterial respiratory vaccine (BRV) was developed and tested for its safety and efficacy. BRV was composed of two immunogens and five bacterins. These were leukotoxoid and bacterin of Mannheimia haemolytica type A, outer membrane protein and bacterin of Pasteurella multocida type A, and bacterins of Haemophilus somnus, Mycoplasma bovis, and Arcanobacterium pyogenes. ELISA antibody titers to five bacterial antigens in vaccinated guinea pigs increased, compared with those in unvaccinated ones. BRV was safe for calves and pregnant cattle in this study. In calves challenged with M. haemolytica and P. multocida, the average daily weight gain and antibody titers of vaccinated calves increased, and respiratory symptoms (P<0.05) and treatment frequency (P<0.01) of vaccinated calves significantly decreased, compared with those of unvaccinated calves. Interestingly, the antibody titers of M. haemolytica leukotoxoid and Mycoplasma bovis were closely related with the reduction of respiratory symptoms. BRV would be an ecomonical measure for the protection against bovine bacterial respiratory diseases.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号