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 281 毫秒
1.
Induction of effective immunity requires the delivery of a protective antigen with appropriate co-stimulatory signals. For bovine viral diarrhoea virus (BVDV) this antigen is the major viral glycoprotein E2. Neutralising antibodies are directed towards the E2 protein and passive transfer of antibodies in serum or colostrum can completely protect against viral infection. DNA vaccination of mice with a construct encoding the E2 glycoprotein induced neutralising antibody levels that were potentially sufficient to prevent virus replication in a challenge system. The co-delivery of interleukin-2 (IL-2) further enhanced the levels of antibody raised. The strong IgG2a component of the antigen-specific antibody suggests a Th1 bias to the immune response induced following vaccination.  相似文献   

2.
An inactivated vaccine containing BVDV I and II strains (PT810; BVDV I, and 890; BVDV II) and using different adjuvants and antigen dosages was tested in a cattle challenge model. Groups of six healthy, seronegative cattle were vaccinated twice with a low dose (10(6.6) TCID(50) PT810 and 10(7.2) TCID(50) 890) vaccine with the adjuvant Bay R1005 or a high dose (10(7.8) TCID(50) PT810 and 10(8. 2) TCID(50) 890) vaccine with two different adjuvants (Bay R1005 or Polygen). Thirty-eight days after the second vaccination, immunised animals (n=18) and non-vaccinated control animals (n=3) were challenged intranasally with 10(6) TCID(50) BVDV strain PT810. For a period of 16 days, virus was isolated from blood leukocytes and nasal swabs, and neutralising antibody titres were determined.The induction of antibodies following immunisation was strongly dependent on the antigen dosage in the vaccine. The high dose formulation induced high serum neutralising antibody titres against both genotypes of up to 32000 after the second immunisation. Animals with neutralising antibody titres >512 (n=14) did not show any marked leukopenia after challenge and only very little or no virus could be isolated from blood leukocytes and/or nasal swabs when compared to control cattle. Furthermore, some of these animals did not show any boost of neutralising or even NS3-specific antibodies, which renders viral replication unlikely and thus would prevent infection of the fetus. Both adjuvants (Bay R1005 or Polygen) were similarly efficient and induced nearly identical antibody responses. In contrast, four of the six low dosage vaccinates had a marked leukopenia and viraemia as well as detectable nasal virus shedding for several days.We conclude that the selected strains and the system of vaccine preparation with high BVDV antigen dosages and highly efficient new adjuvants provide an effective means of protection against BVDV I infections. Investigations to demonstrate the protection against BVDV II infections, the duration of immunity and the ability of fetal protection by using the high dose vaccine in a fetal challenge model will follow.  相似文献   

3.
ABSTRACT: Protection of cattle from alcelaphine herpesvirus-1 (AlHV-1)-induced malignant catarrhal fever (MCF) has been described previously, using an attenuated virus vaccine in an unlicensed adjuvant. The vaccine was hypothesised to induce a protective barrier of virus-neutralising antibody in the oro-nasal region, supported by the observation of high titre neutralising antibodies in nasal secretions of protected animals. Here we describe further analysis of this vaccine strategy, studying the effectiveness of the vaccine formulated with a licensed adjuvant; the duration of immunity induced; and the virus-specific antibody responses in plasma and nasal secretions. The results presented here show that the attenuated AlHV-1 vaccine in a licensed adjuvant protected cattle from fatal intranasal challenge with pathogenic AlHV-1 at three or six months. In addition, animals protected from MCF had significantly higher initial anti-viral antibody titres than animals that succumbed to disease; and these antibody titres remained relatively stable after challenge, while titres in vaccinated animals with MCF increased significantly prior to the onset of clinical disease. These data support the view that a mucosal barrier of neutralising antibody blocks infection of vaccinated animals and suggests that the magnitude of the initial response may correlate with long-term protection. Interestingly, the high titre virus-neutralising antibody responses seen in animals that succumbed to MCF after vaccination were not protective.  相似文献   

4.
A CELL CULTURE VACCINE AGAINST BOVINE EPHEMERAL FEVER   总被引：1，自引：0，他引：1  
SUMMARY A vaccine was prepared from cell culture fluids harvested from the twelfth passage of the 919 strain of bovine ephemeral fever (BEF) virus in Vero cell cultures. Cattle were vaccinated subcutaneously with various combinations of strain 919 virus and adjuvants. Neutralising antibodies were assayed at various times after vaccination and some cattle were challenged by intravenous inoculation with the virulent 417WBC strain of BEF virus. Strain 919 virus of the third and twelfth passage levels in Vero cells produced neither fever, clinical illness nor detectable viraemia in 5 calves inoculated intravenously. Nor could viraemia be detected in 5 heifers receiving vaccine subcutaneously. When the vaccine was administered mixed with aluminium hydroxide adjuvant, the production of neutralising antibodies increased with an increase in the volume of vaccine from 2.5 ml to 10 ml and the response to 2 injections was significantly better than the response to a single injection. The neutralising antibody response was decreased when vaccine was diluted in phosphate buffered saline. The neutralising antibody response following 2 subcutaneous vaccinations with strain 919 virus mixed with aluminium hydroxide adjuvant was higher than that following intravenous inoculation with virulent virus. The vaccine-induced antibodies persisted for at least 12 months, and revaccination at this time led to an increase in the titre of neutralising antibody. Antibodies induced by a single subcutaneous administration of strain 919 virus mixed with Freund's complete adjuvant persisted for at least 40 weeks; those induced by vaccine containing Freund's incomplete adjuvant had virtually disappeared within 16 weeks. All these calves responded to vaccination with aluminium hydroxide-containing vaccine with increases in levels of neutralising antibodies. Of 26 vaccinated calves challenged with virulent BEF virus, 24 remained clinically normal. Two developed brief periods of pyrexia on the seventh day after challenge, but no other clinical signs. One of these calves had a viraemia that was demonstrated only by intravenous inoculation of a susceptible calf. The remaining calf had no detectable viraemia. All of 7 unvaccinated calves developed severe clinical BEF within 5 days of challenge. No disease attributable to the 919 virus occurred in 24 vaccinated pregnant heifers or their newborn calves.  相似文献   

5.
Samples of pharyngeal fluid and serum were collected from cattle after exposure to live foot-and-mouth disease (FMD) virus (with or without prior vaccination) or after subcutaneous vaccination with inactivated virus. The pharyngeal fluid samples were examined for FMD neutralising activity and specific anti-FMD IgG, IgM and IgA antibodies. The neutralising activity of the serum was also monitored. A peak of neutralising activity which occurred in the pharyngeal fluid of unvaccinated cattle seven days after virus exposure corresponded to a rise in specific IgM and IgA antibodies. This peak appeared to be due to serum and tissue fluid escaping from the damaged mucosa during the acute inflammatory phase of infection. At later stages (20 to 60 days after virus exposure) the pharyngeal fluid neutralising activity corresponded to a rise in specific IgA antibodies, suggesting that active local antibody production was taking place. The pharyngeal fluid neutralising activity detected after revaccination with oil emulsion or aqueous vaccines, without exposure to live virus, corresponded to a rise in specific IgG and IgM antibody levels and this may have been due to serum transudation.  相似文献   

6.
Cats were vaccinated with one of the three preparations: purified feline immunodeficiency virus (FIV) incorporated into immune stimulating complexes (ISCOMs), recombinant FIV p24 ISCOMs, or a fixed, inactivated cell vaccine in quil A. Cats inoculated with the FIV ISCOMs or the recombinant p24 ISCOMs developed high titres of antibodies against the core protein p24 but had no detectable antibodies against the env protein gp120 or virus neutralising antibodies. In contrast, all of the cats inoculated with the fixed, inactivated cell vaccine developed anti-env antibodies and four of five had detectable levels of neutralising antibody. However, none of the vaccinated cats were protected from infection after intraperitoneal challenge with 20 infectious units of FIV. Indeed there appeared to be enhancement of infection after vaccination as the vaccinated cats become viraemic sooner than the unvaccinated controls, and 100% of the vaccinated cats became viraemic compared with 78% of the controls. The mechanism responsible for this enhancement remains unknown.  相似文献   

7.
The pathogenicity of a field strain, 417, of bovine ephemeral fever (BEF) virus for newborn and young calves was investigated. Three colostrum-deprived newborn calves inoculated intravenously developed severe clinical disease and viraemia, and produced long-lasting neutralising antibody. The incubation period in these animals was 10 and 11 days, compared with 5 to 7 days for older calves. Two newborn calves which received colostrum from immune dams and 2 which received colostrum from non-immune dams failed to respond clinically to intravenous inoculation with strain 417. The neutralising antibody response of these calves was of short duration. Four calves, 7 to 8 weeks old and lacking detectable neutralising antibody to BEF virus, or having low levels of antibody, did not develop clinical disease when inoculated intravenously. Four calves 12 to 14 weeks of age and free of detectable neutralising antibody to BEF virus developed clinical disease when inoculated with strain 417.  相似文献   

8.
Three different pools of the CSIRO 16 strain of Akabane virus differing in their laboratory passage histories were used to inoculate 39 ewes between 32 and 36 days pregnant; 22 pregnant ewes received inocula containing no virus. There was no difference in the development, duration and titre of the viraemia and neutralising antibody response between the three infected groups of ewes. Both infected and control ewes had 141% foetuses when autopsied at 69 to 105 days gestation. Of the 55 foetuses from infected ewes 44 (80%) had gross developmental abnormalities.At autopsy of the dams Akabane virus was isolated only from the uterine caruncle. From foetal samples virus was isolated from a wide range of tissues, from one foetus at 69 days and from the blood of four foetuses at 95 to 106 days gestation. Virus was also isolated from 24 of the choriolllantoic fluid samples and from 37 placentomes of the 44 foetuses with developmental defects, in concentrations ranging from 102 to 105.5 TCID50/ml or/g. No virus was isolated from the tissues of the control ewes or their foetuses.Neutralising antibody to Akabane virus was detected in 78% of the foetal sera from the infected group, titres ranging from 2 to 64. IgM and IgG1 and neutralising antibody were detected in sera of 40 foetuses with developmental abnormalities including three that were of 76 to 78 days gestation. Neutralising antibody was detected only in serum that contained IgG1 but may also have been associated with IgM in infected foetuses. IgM was detected in the serum of most foetuses including the non-infected controls, but sera from the control foetuses did not contain IgG1 or neutralising antibody to Akabane virus. No IgG2 or IgA were detected in any foetal serum.  相似文献   

9.
Pregnant sows were inoculated with inactivated transmissible gastroenteritis virus and with preparations of virus surface projections and subviral particles derived by detergent treatment of the virus. Neutralising antibody was demonstrated in serum and colostrum from animals that received whole virus or preparations of surface projections whereas subviral particles failed to stimulate neutralising antibody formation. Similar results were obtained with serum from rabbits inoculated with whole virus and structural components. All three preparations stimulated the formation of agglutinating antibodies, as demonstrated by sedimentation analysis and filtration studies with radiolabelled virus.The immunoglobulin classes responsible for neutralising antibody activity in sows inoculated by the intramammary route were examined. In each case where the immunoglobulin class was determined, IgG was found. One sow that received surface projections also had IgA with neutralising activity in her colostrum. In contrast, infection of sows with live whole virus resulted in neutralising antibody of the IgG, IgM and IgA classes.  相似文献   

10.
This study determined the proportion of captive juvenile and adult African wild dogs (Lycaon pictus) that developed protective titres of rabies neutralising antibodies following ingestion of a chicken head bait/SAG-2 oral rabies vaccine combination. A single chicken head containing 1.8 ml of SAG-2 vaccine (10(8.0) TCID50/ml) in a plastic blister was fed to each of eight adult and three juvenile wild dogs. Bait ingestion resulted in a significant rise in serum neutralising antibody titres. Overall seroconversion rate was eight out of 11 (72.7%), and all the puppies and five out of eight (62.5%) adults showed potentially protective levels of antibodies on day 31. The mean post-vaccination neutralising antibody titre was within the range reported to be protective against challenge with virulent rabies virus in other species.  相似文献   

11.
The nasal and serum neutralising antibody responses of lambs was compared following vaccination with live or inactivated parainfluenza 3 (PI 3) virus by either intramuscular (IM) or intranasal (IN) routes. Nasal antibody was only detected following inoculation of live virus IN or inactivated virus in Freund's complete adjuvant (FCA) IM. Immunity to aerosol challenge, as assessed by viral shedding from the nose, was conferred by (1) live virus administered by either route, (2) two IM inoculations of inactivated virus in FCA, and (3) one IM injection of inactivated virus in FCA followed by IN instillation of inactivated virus.  相似文献   

12.
THE PATHOGENESIS OF INFECTIOUS AVIAN ENCEPHALOMYELITIS   总被引：1，自引：0，他引：1  
An association was demonstrated between the development of clinical infectious avian encephalomyelitis (IAE), the persistence and titre of infectious avian encephalomyelitis virus (IAEV) in the brain of the chicken, the duration of detectable viraemia and the age of the chicken at the time of infection with the virus. The older the chicken at the time of infection the milder the disease, the lower the virus titre in the brain and the shorter the period of viraemia. IAEV serum neutralising antibody was produced earlier after infection in older chickens, and its detection was associated with decreasing virus titres in the brain and the cessation of detectable viraemia. Treatment of chickens with testosterone in ova, to inhibit the development of antibody synthesis, prevented the onset of age-associated resistance and testosterone treated birds were as susceptible to clinical IAE as baby chickens. The results suggested that the ability to produce IAEV serum neutralising antibody was an important component of age-associated resistance to IAE.  相似文献   

13.
Six pregnant heifers that were experimentally infected with bovine ephemeral fever virus produced normal calves. Foetuses of 8 heifers that were immune to bovine ephemeral fever were inoculated with bovine ephemeral fever virus. One was aborted after 36 days, but the cause of abortion could not be determined. One was sacrificed after 28 days. The foetus and its membranes were normal and neither virus nor antibody was demonstrated. The other 6 heifers produced normal calves. One calf, 501, inoculated after 160 days gestation, contained high levels of neutralising antibody in serum before ingestion of colostrum. The others, inoculated at gestational ages of 52 days to 157 days showed no evidence of neutralising antibody in blood samples collected at birth.  相似文献   

14.
It is widely held that only cells of canine origin support canine herpesvirus-1 (CHV-1) replication and, that cytopathic effect (CPE) develops relatively slowly. Here we show that mink fetal lung cells (NBL-7 cell line) are permissive for CHV-1 and can be used to produce a sensitive test for neutralising antibody by plaque reduction in the presence of complement. The test was applied to the investigation of CHV-1 virus neutralising antibody levels in three kennel populations. The results showed that 26 out of 28 dogs were neutralising antibody positive (titre >/=2), and, 11 out of 28 had titres of >/=1024. The serum samples were analysed by enzyme linked immunoassay (ELISA); 27 out of 28 were graded as ELISA IgG positive (titre >/=500) and 26 of 28 were graded as ELISA IgM positive (titre >/=50).  相似文献   

15.
Several laboratory studies assessed the duration of immunity of a quadrivalent vaccine (Rispoval™4, Pfizer Animal Health) against bovine respiratory diseases (BRD) caused by bovine herpes-virus type-1 (BHV-1), parainfluenza type-3 virus (PI3V), bovine viral-diarrhoea virus type 1 (BVDV), or bovine respiratory syncytial virus (BRSV). Calves between 7 weeks and 6 months of age were allocated to treatment and then were injected with two doses of either the vaccine or the placebo 3 weeks apart. Six to 12 months after the second injection, animals were challenged with BHV-1 (n = 16), PI3V (n = 31), BVDV (n = 16), or BRSV (n = 20) and the course of viral infection was monitored by serological, haematological (in the BVDV study only), clinical, and virological means for ≥2 weeks. Infection induced mild clinical signs of respiratory disease and elevated rectal temperature in both vaccinated and control animals and was followed by a dramatic rise in neutralising antibodies in all treatment groups. Titres reached higher levels in vaccinated calves than in control calves after challenge with BHV-1, BVDV, or BRSV. On day 3 after PI3V challenge, virus shedding was reduced from 3.64 log10 TCID50 in control animals to 2.59 log10 TCID50 in vaccinated animals. On days 6 and 8 after BRSV challenge, there were fewer vaccinated animals (n = 2/10 and 0/10, respectively) shedding the virus than control animals (n = 8/10 and 3/10, respectively). Moreover, after challenge, the mean duration of virus shedding was reduced from 3.8 days in control animals to 1 day in vaccinated animals in the BVDV study and from 3.4 days in control animals to 1.2 days in vaccinated animals in the BRSV study. The duration of immunity of ≥6 months for PI3V, BHV-1 and BVDV, and 12 months for BRSV, after vaccination with Rispoval™4, was associated mainly with enhanced post-challenge antibody response to all four viruses and reduction of the amount or duration of virus shedding or both.  相似文献   

16.
A group of British sheep was infected with bluetongue virus 5 (BTV5) and subsequently challenged with the same virus type. Protection from this challenge and a homotypic BTV neutralising antibody response were observed. A second group of sheep was infected serially with three different BTV types. Animals previously exposed to BTV4 and BTV3 were found to be resistant to challenge by BTV6. Animals infected with BTV4 and challenged with BTV3 were shown to produce a transient heterotypic neutralising antibody response to a number of types. Although the level of this heterotypic response diminished with time, after challenge with BTV6 these animals developed a similar broad heterotypic response. The nature of this response and its implications in terms of observed protection merit consideration in future vaccine design and evaluation of field survey work.  相似文献   

17.
Equine herpesvirus-1 (EHV-1) glycoproteins H, and L (gH and gL) expressed individually or co-expressed by recombinant baculoviruses were used to immunise BALB/c mice prior to intranasal challenge in a murine model of respiratory infection. Only the co-expressed material (EHV-1 gH/gL) induced neutralising antibody (low levels). The same immunogen also produced the strongest cellular responses. Immunisation with gH/gL and, to a lesser extent, with gH alone was associated with a reduction of virus load in nasal turbinates and olfactory bulbs after challenge infection. Viraemia, detected by polymerase chain reaction, was also reduced. No such protective effects were observed for gL alone. Adoptive transfer of lymphocytes from gH/gL-immunised mice to näive mice subsequently challenged with EHV-1 indicated that both CD4+ and CD8+ cells had a role in protective immunity. Although clearance of EHV-1 from respiratory tissue was not as effective as previously found for glycoproteins D or C, these experiments provide evidence that the co-expression of EHV-1 gL with gH generates a conformational neutralising epitope which is not present in either molecule alone, and suggests that gH/gL antigen may have a better potential as a component of an EHV-1 vaccine than gH alone.  相似文献   

18.
Goats vaccinated with attenuated rinderpest were protected from peste-des-petits-ruminants virus for at least 12 months; vaccinated animals were unable to transmit the challenge virus. Before challenge neutralising antibodies were directed primarily against rinderpest but following exposure to peste-des-petits-ruminants, a high antibody level to both viruses was found.  相似文献   

19.
Levels of passively transferred maternal antibodies to three canine viruses, rabies virus (RV), canine distemper virus (CDV) and infectious canine hepatitis (ICH) virus, in serum specimens from 14 fetal pups and in serial serum specimens collected up to 45 days after whelping from 14 neonate pups were compared with levels of antibodies to these viruses in milk and sera collected concurrently from their respective dams. Radioimmunoassays using RV-, CDV- and ICH virus-specific antigens showed that sera from all fetal pups had detectable levels of antibodies to all three canine viruses and ICH neutralising antibodies were detected in sera from 10 of the 14 fetal pups. As the time after whelping increased, titres of RV-, CDV- and ICH virus antibodies measured by radioimmunoassay and ICH virus neutralising antibody tests in serially collected specimens of milk from dams rapidly decreased, while titres of the antibodies in serum specimens from newborn pups in their litters steadily decreased. Individual fetal and newborn pups with a high titre of antibody to one virus also had high titres to the other two viruses, although a wide range of titres was observed among pups in each of the litters studied. Markedly higher titres of antibody to all three viruses were observed in serially collected specimens of sera from dams than in sera from fetal and newborn pups in their litters. Results show that maternal RV, CDV and ICH virus antibodies are transferred from dams to pups in utero and by nursing. Levels of these maternal virus-specific antibodies in newborn pup sera decreased at similar rates as time after whelping increased.  相似文献   

20.
Vulvovaginitis of goats due to a herpesvirus   总被引：2，自引：0，他引：2  
Two concurrent outbreaks of genital disease in goats were associated with infection by a herpesvirus that was isolated from vulval and vaginal lesions of affected does. Serum neutralising antibody to the virus was present both in goats with the clinical disease and some unaffected goats. Of 19 goat herds examined only 4 had serum neutralising antibody positive goats with low (5%) to high (60%) incidence of infection. The virus isolate was characterised as a herpesvirus on its physico-chemical and morphological features. It contained DNA and was inactivated at low pH and by treatment with lipid solvents and trypsin. The virus particles were icosahedral, consisting of a nucleocapsid surrounded by an envelope membrane and measured approximately 150 nm in diameter. The virus was serologically related to a New Zealand isolate of caprine herpesvirus (NZ-CpHV), associated with similar genital disease, and was distinct from bovine herpes virus-1 (BHV-1) showing a one way neutralisation pattern.  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