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1.
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2.
This study was conducted to determine whether young calves with maternal antibodies against bovine herpesvirus type 1 (BHV-1) but without antibodies against glycoprotein E (gE) can produce an active antibody response to gE after a BHV-1 infection. Five calves received at birth colostrum from gE-seronegative cows which had been vaccinated two or three times with an inactivated BHV-1, gE-deleted marker vaccine. After inoculation with a wild-type virulent strain of BHV-1, all the passively immunised gE-negative calves shed virus in large amounts in their nasal secretions. All the calves seroconverted to gE within two to four weeks after inoculation and then had high levels of gE antibodies for at least four months. The development of an active cell-mediated immune response was also detected by in vitro BHV-1-specific interferon-gamma assays. All the calves were latently infected, because one of them re-excreted the virus spontaneously and the other four did so after being treated with dexamethasone. The results showed that under the conditions of this work the gE-negative marker could also distinguish between passively immunised and latently infected calves.  相似文献   

3.
In this study, we examined the functional role of bovine herpesvirus type 1 (BHV-1) Us9 acidic domain residues 83-90 in the anterograde axonal transport of the virus in calves (natural host), rabbits, and in cultured neurons. A mutant virus strain lacking Us9 residues 83-90 (BHV-1 Us9 Δ83-90) and the rescued virus (BHV-1 Us9 R83-90) replicated efficiently in the nasal and ocular epithelium during primary infection and established latency in the trigeminal ganglia (TG). However, upon reactivation from latency, only the BHV-1 Us9 R83-90 virus was detected in nasal and ocular swabs of animals. In compartmentalized, rabbit primary dorsal root ganglia (DRG) neuron cultures, the Us9-deleted BHV-1, BHV-1 Us9 Δ83-90 and BHV-1 Us9 R83-90 viruses were transported efficiently in the retrograde direction. However, only the BHV-1 Us9 R83-90 virus was transported in an anterograde direction. These studies suggested that the Us9 acidic domain residues located between 83 and 90 were required for axonal anterograde transport.  相似文献   

4.
Four bovine herpesvirus-1 (BHV-1) commercial vaccines, three of which (vaccines B, D, E) were modified live vaccines (MLV) and one (vaccine A) identified as a live strain of BHV-1 gE negative, were used for vaccination of calves, using three calves for each vaccine. Three months after vaccination calves were subjected to dexamethasone (DMS) treatment following which virus was recovered from calves inoculated with vaccine B and from those given vaccine D. No virus reactivation was obtained in calves, which received vaccines A or E. The DNA extracted from the two reactivated viruses was subjected to restriction endonuclease analysis. The restriction pattern of the isolate obtained from calves vaccinated with vaccine D differs significantly from that of the original vaccine, whereas the reactivated virus from calves given vaccine B conserved the general pattern of the original vaccine strain. For each reactivated virus in this experiment (B and D) as well as for the isolate obtained from calves vaccinated with a further MLV (vaccine C) in a previous trial, three calves were inoculated. No clinical signs of disease were detected in any of the inoculated calves during the observation period. When the nine calves were exposed 40 days later to challenge infection with virulent BHV-1, they remained healthy and no virus was isolated from their nasal swabbings. These results indicate that some BHV-1 vaccines considered in the project can establish latency in the vaccinated calves, however, the latency does not appear to interfere with the original properties of the vaccines in terms of safety and efficacy.  相似文献   

5.
Bovine herpesvirus type 5 (BHV-5) infection in calves causes meningoencephalitis, a fatal disease highly prevalent in South America. To study the pathogenesis of BHV-5 infection in cattle, 12 calves (group 1: acute infection) and 11 calves (group 2: latent infection) were intranasally inoculated with an Argentinean BHV-5 isolate at 10(8) and 10(4.7) tissue culture infective doses, respectively; six calves (control group) were mock infected. At 3 months postinoculation, all of the calves in group 2 and three calves in group 3 were given dexamethasone to reactivate the virus. The animals were euthanatized between days 6 and 17 postinoculation (group 1) and between days 6 and 16 postreactivation (group 2). Seventy-five percent and 91% of animals in groups 1 and 2, respectively, excreted BHV-5 in nasal and ocular discharges. Following dexamethasone administration, 45% of calves shed virus in both types of secretions. Spontaneous virus reactivation and shedding was observed in one calf. Neurologic signs consisting of circling, teeth grinding, ptyalism, jaw chomping, tongue protrusion, and apathy were observed in two animals in group 1 and, during the reactivation period, in four animals in group 2. Macroscopic findings consisted of softening of the cerebral tissue, meningeal hemorrhages and swelling, and edema and hemorrhages of prescapular, retropharyngeal and submandibular lymph nodes. Histologic lesions consisted of meningitis, mononuclear perivascular cuffing, neuronophagia, satellitosis, gliosis, hemorrhage, and necrosis and edema. Lesions in anterior cerebral cortex, medulla, and pons were consistently seen in all the animals of group 1. In the acutely infected animals, lesions in the diencephalon appeared at day 10 postinoculation, whereas in the latently infected calves these lesions were observed as early as at day 6 postreactivation. Latently infected animals developed lesions simultaneously in anterior cortex, medulla, pons, and diencephalon, showing a remarkable difference from the acutely infected group. Trigeminal ganglionitis appeared relatively early in animals of both groups (day 7 postinoculation in group 1 and day 8 postreactivation in group 2).  相似文献   

6.
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7.
This study was conducted to investigate the glycoprotein E (gE) antibody response raised after inoculation with a low infectious dose of bovine herpesvirus 1 (BHV-1) in six calves possessing high levels of passive immunity from cows repeatedly vaccinated with gE deleted marker vaccine. Four out of the six calves developed gE antibodies 3-5 weeks after infection, whereas the two other ones remained seronegative to gE. After 5 months of infection, the six calves were treated with dexamethasone. Virus was only re-excreted by the four calves which previously seroconverted against gE. The two other calves became seronegative against BHV-1, 30-32 weeks after infection. A second dexamethasone treatment performed 11 months after infection failed to demonstrate a latent infection in these two calves. Moreover, the lack of identification of a cell-mediated immune response, after the two dexamethasone treatments, and the failure to detect BHV-1 DNA sequences in trigeminal ganglia strongly suggest that these two calves were not latently infected. In conclusion, the presence of high levels of maternal immunity lacking gE antibodies does not prevent latency after infection with a low titre of BHV-1. Moreover, latency is associated with a serological response to gE. These results confirm that the gE deletion is a good marker to identify young calves latently infected with a field virus.  相似文献   

8.
Twelve calves infected with bovine herpesvirus type 1 (BHV-1) were killed when in a latent state of infection. Latency was verified 30 days after virus inoculation of the calves by seroconversion, absence of virus shedding, and in 2 calves, by recrudescence of the infection after they were treated with dexamethasone. By in situ hybridization techniques and autoradiography, DNA of BHV-1 was detected in 13 of 23 trigeminal ganglia of latently infected calves. Viral DNA was restricted to the nucleus of nerve cells. Single neurons harboring BHV-1 DNA were observed in 4.9% of the sections (n = 325) of the trigeminal ganglia. The results obtained correspond to those known from herpes simplex virus infections in mice. The implications for the virus-host relationship are discussed.  相似文献   

9.
Latent bovine herpesvirus-1 (BHV-1) infection was established in 6 calves and was demonstrated by reinduction of virus shedding after administration of corticosteroids. Latently infected calves failed to transmit BHV-1 during 4 weeks' contact with sentinel calves. Infected calves were killed and necropsied during latency or induced recrudescence. The BHV-1 DNA was demonstrated intranuclearly in trigeminal ganglion neurons by in situ hybridization. The BHV-1 antigen was demonstrated by immunofluorescence in trigeminal ganglion neurons during recrudescence. By electron microscopy, changes in the appearance of the Nissl bodies and a high frequency of nuclear bodies were observed in trigeminal ganglion neurons.  相似文献   

10.
In this work, a role for the genes encoding glycoproteins I (gI) and E (gE) and the US9 protein of bovine herpesvirus type 5 (BHV-5) in neuropathogenicity and reactivation of latent infections was examined. Calves infected intranasally with a gI/gE/US9 deleted recombinant shed up to 10(2.85) TCID50/ml infectious virus in nasal secretions. Calves infected with the wild type BHV-5 parental virus shed up to 10(5) TCID50/ml virus. No signs of disease were observed in calves infected with the recombinant virus, whereas those infected with wild type virus displayed respiratory and neurological signs. The recombinant was only able to reach the basal portions of the central nervous system. In contrast, wild type virus was found widespread within the brain. Reactivation with dexamethasone 60 days post-infection resulted in reactivation of wild type virus, whereas the recombinant virus could not be reactivated. These studies demonstrate that genes gI, gE and US9 of BHV-5 are important for its neuropathogenicity and its ability to reactive from latency.  相似文献   

11.
Recrudescence of bovine herpesvirus-5 in experimentally infected calves   总被引：2，自引：0，他引：2  
A latent infection of bovine herpesvirus-5 (BHV-5) was established in 4 calves. These calves, plus 2 controls, were given dexamethasone (DM) to reactivate the latent virus. The 4 principal calves developed antibodies to BHV-5 by postinoculation day (PID) 21. Antibody titers increased until PID 42 before decreasing to low levels of PID 75. After the first DM treatment (started on PID 76), an anamnestic antibody response was demonstrated in the 4 principal calves. Calves, 2, 3, and 4 were euthanatized and necropsied at PID 121, and their antibody titers were again decreasing. The virus BHV-5 was not isolated from the tissues by conventional techniques of viral isolation but was isolated from the trigeminal ganglion and spinal cord of calf 3 by explantation techniques. The BHV-5 was isolated, using conventional viral isolation techniques, from a nasal swab sample of calf 1 on PID 91 (15 days after the first DM treatment) and from the thoracic lymph node 6 days after the start of a 2nd DM treatment. Seemingly, BHV-5 may be latently harbored in the nerve tissues or calves and this virus may be reactivated from the upper respiratory tract following subsequent DM treatment.  相似文献   

12.
Calves infected with bovine herpesvirus-1 (BHV-1) or both BHV-1 and parainfluenza-3 virus (PIV-3) developed clinical signs including fever, cough, and nasal and ocular discharges. Animals infected with both viruses appeared more depressed and showed higher rectal temperature, while calves inoculated with PIV-3 alone had a very mild clinical disease. Both BHV-1 and PIV-3 were recovered from nasal secretions up to six to eight days postinoculation. However, the virus titers were lower in calves with mixed infection. An increase in serum antibodies to both BHV-1 and PIV-3 was detected by serum neutralization and enzyme-linked immunosorbent assay. Antibody responses were delayed and significantly lower in calves given mixed infection than in calves infected with a single virus. Interleukin-2 activity in cultures of lymphocytes from BHV-1 and BHV-1 plus PIV-3 infected calves was higher compared to control calves.  相似文献   

13.
OBJECTIVE: To determine the efficacy of a modified-live virus vaccine containing bovine herpes virus 1 (BHV-1), bovine respiratory syncytial virus (BRSV), parainfluenza virus 3, and bovine viral diarrhea virus (BVDV) types 1 and 2 to induce neutralizing antibodies and cell-mediated immunity in na?ve cattle and protect against BHV-1 challenge. ANIMALS: 17 calves. PROCEDURES: 8 calves were mock-vaccinated with saline (0.9% NaCl) solution (control calves), and 9 calves were vaccinated at 15 to 16 weeks of age. All calves were challenged with BHV-1 25 weeks after vaccination. Neutralizing antibodies and T-cell responsiveness were tested on the day of vaccination and periodically after vaccination and BHV-1 challenge. Specific T-cell responses were evaluated by comparing CD25 upregulation and intracellular interferon-gamma expression by 5-color flow cytometry. Titration of BHV-1 in nasal secretions was performed daily after challenge. Results-Vaccinated calves seroconverted by week 4 after vaccination. Antigen-specific cell-mediated immune responses, by CD25 expression index, were significantly higher in vaccinated calves than control calves. Compared with control calves, antigen-specific interferon-gamma expression was significantly higher in calves during weeks 4 to 8 after vaccination, declining by week 24. After BHV-1 challenge, both neutralizing antibodies and T-cell responses of vaccinated calves had anamnestic responses to BHV-1. Vaccinated calves shed virus in nasal secretions at significantly lower titers for a shorter period and had significantly lower rectal temperatures than control calves. CONCLUSION AND CLINICAL RELEVANCE: A single dose of vaccine effectively induced humoral and cellular immune responses against BHV-1, BRSV, and BVDV types 1 and 2 and protected calves after BHV-1 challenge for 6 months after vaccination.  相似文献   

14.
A study was carried out to determine whether bovid herpesvirus-2 (BHV-2) is able to induce a recurrent infection in experimentally infected calves. Twelve calves infected with the virus were treated with dexamethasone (DMS) beginning 69 days after the infection, ie, several weeks after the animals had recovered from the disease and were negative for BHV-2. The stress induced by DMS treatment failed to reactivate the clinical condition or to induce shedding of BHV-2. However, treatment with DMS reactivated a latent infectious bovine rhinotracheitis (IBR) virus infection in all calves previously inoculated with BHV-2, and also in 2 noninoculated controls. The reactivation of IBR virus occurred without any clinical evidence of the disease, but the virus was isolated from nasal and pharyngeal swabbings and from the organs. A proliferative ganglionitis of the trigeminal ganglion was also observed. Because of the interference by IBR virus, this study did not resolve the question as to whether BHV-2 can induce a recurrent infection.  相似文献   

15.
Bovine herpesvirus type 1 (BHV-1) envelope protein U(L)49.5 inhibits transporter associated with antigen processing (TAP) and down-regulates cell-surface expression of major histocompatibility complex (MHC) class I molecules to promote immune evasion. Earlier, we have constructed a BHV-1U(L)49.5Δ30-32 CT-null virus and determined that in the infected cells, TAP inhibition and MHC-I down regulation properties of the virus are abolished. In this study, we compared the pathogenicity and immune responses in calves infected with BHV-1U(L)49.5Δ30-32 CT-null and BHV-1 wt viruses. Following primary infection, both BHV-1 wt and BHV-1U(L)49.5Δ30-32 CT-null virus replicated in the nasal epithelium with very similar yields. BHV-1 antigen-specific CD8+ T cell proliferation as well as CD8+ T cell cytotoxicity in calves infected with the BHV-1U(L)49.5Δ30-32 CT-null virus peaked by 7 dpi (P<0.05) which is 7 days earlier than that of BHV-1 wt-infected calves. Further, virus neutralizing antibody (VN Ab) titers and IFN-γ producing peripheral blood mononuclear cells (PBMCs) in the U(L)49.5 mutant virus-infected calves, also peaked 7 days (IFN-γ; P<0.05) and 14 days (VN Ab; P<0.05) earlier, respectively. Therefore, relative to wt in the BHV-1U(L)49.5 mutant virus-infected calves, primary neutralizing antibody and cellular immune responses were induced significantly more rapidly.  相似文献   

16.
Eight separate, but related experiments, were carried out in which groups of six calves were vaccinated with one of eight commercial vaccines. In each experiment the vaccinated calves were subsequently exposed to three calves infected with virulent bovine herpesvirus-1 (BHV-1). In each experiment, all infected donor calves developed a typical severe infectious bovine rhinotracheitis (IBR) infection and excreted virus in their nasal secretions of up to 10(8.00) TCID50/0.1 ml. One live BHV-1 gE-negative vaccine (A) and three modified live vaccines (B, C, D), administered intranasally, all protected against clinical disease. The calves vaccinated with one vaccine (C) also did not excrete virus in the nasal secretions, whereas the calves protected by vaccines A, B and D excreted virus in their nasal secretions but at low titres (10(0.66)-10(1.24) TCID50/0.1 ml). A fourth modified live vaccine (E), given intramuscularly, failed to prevent mild clinical disease in the calves which also excreted virus in the nasal secretions at titre of 10(1.00) TCID50/0.1 ml. An analogous result was given by the calves vaccinated with either of the two inactivated vaccines (F and G) or with a BHV-1 subunit vaccine (H). All calves developed mild clinical signs and excreted virus at titres of 10(2.20)-10(3.12) TCID50/0.1 ml. Calves vaccinated with C vaccine were subsequently given dexamethasone, following which virus was recovered from their nasal secretions. The virus isolates did not cause disease when calves were infected and appeared to be closely related to the vaccine strain.  相似文献   

17.
Calves not vaccinated with infectious bovine rhinotracheitis virus (IBRV) became latently infected when challenge exposed and treated with dexamethasone (DM). Calves that shed IBRV after DM treatment were considered to be latently infected. Vaccination with a temperature-sensitive intranasal vaccine or with formalinized IBRV in Freund's complete adjuvant (IBRV-FCA) protected some, but not all, calves against latent infection--indicating a role for the immune response in preventing latent infection. That all latently infected calves were not detected after DM treatment was indicated by the fact that after a 2nd DM treatment of 3 calves treated 6 months previously and not found to shed virus, 1 of the calves was latently infected. Latently infected calves were inoculated with successive doses of IBRV-FCA and treated with DM. Nonvaccinated calves shed virus, whereas vaccinated calves similarly treated did not shed virus. Because both groups had a comparable cell-mediated immune response, as determined by blastogenic response to IBRV, but the vaccinated group had significantly higher virus-neutralizing antibody titers, a role for humoral antibody in preventing viral shedding was indicated.  相似文献   

18.
Four Merino lambs were intranasally inoculated with bovine herpesvirus type 5 (BHV-5) reference strain N569. Two lambs were mock-inoculated as negative controls. The virus-inoculated animals developed apathy, inappetence, rhinitis, nasal, ocular and genital discharge, slight diarrhea and neurological disorders, like tremor and salivation. BHV-5 was isolated from the nasal discharge in two of the animals, while the polymerase chain reaction (PCR) detected the virus in all the infected lambs. Two lambs died on post infection day (PID) 13, while the other two infected animals were euthanized on PID 15 and 30. Gross pathological changes were not observed, however, histopathological examinations revealed diffuse nonsuppurative meningo-encephalitis in all infected animals. Viral antigen was detected by immunohistochemistry and viral nucleic acid was revealed by in situ hybridization in the brain of the two lambs, which died on PID 13. The virus was demonstrated by virus isolation and by PCR from different organs of all the infected animals. Slight rise of antibodies was observed in the infected animals from PID 15. The results show that BHV-5 is able to cross the species barrier and may establish infection in sheep.  相似文献   

19.
The in vivo administration of bovine recombinant interleukin-2 (rIL-2) was evaluated in calves vaccinated and then challenged with bovine herpesvirus-1 (BHV-1). In Experiment 1, 24 calves were allotted to four groups: control; bovine rIL-2; BHV-1 vaccine (modified-live); and bovine rIL-2 + BHV-1 vaccine. Serum neutralizing antibody titers to BHV-1 were increased sixfold, and virus shedding was fourfold less in calves vaccinated and treated with rIL-2 (25 micrograms/kg, intramuscularly) when compared to calves that received vaccine only. Treatment with rIL-2 induced lymphokine-activated killer activity that was eliminated by pretreating effector cells with complement and a monoclonal antibody (B26A) specific for the sheep red blood cell receptor. The rIL-2 treatment in BHV-1-vaccinated calves increased the calves' ability to withstand a BHV-1 challenge. However, during treatment with rIL-2, calves developed diarrhea and mild fever that abated after IL-2 treatment was stopped. A second experiment was then conducted to determine a dose of rIL-2 that would enhance immunity to BHV-1 without causing adverse side effects. Twenty-five calves were allotted to five groups that received injections of rIL-2 at 0.0, 25.0, 2.5, 0.25, or 0.025 micrograms kg-1 day-1 for 5 days. All calves received a modified-live BHV-1 vaccine. Calves treated with 25.0 micrograms kg-1 day-1 showed similar adverse side effects as in the first experiment but all other calves were normal. Compared to control calves, those treated with 25.0, 2.5, and 0.25 micrograms kg-1 day-1 of rIL-2 had higher (P less than 0.05) serum antibody titers to BHV-1 and following challenge lower (P less than 0.05) BHV-1 titers in nasal secretions; additionally, clinical disease as evidenced by nasal and ocular discharge was less severe (P less than 0.05). In vitro cytotoxic responses against BHV-1-infected bovine kidney cells were increased (P less than 0.05) in calves treated with rIL-2 in a dose dependent manner. These data suggest that bovine rIL-2 at 2.5 to 0.25 micrograms/kg may be an effective adjuvant to immunization.  相似文献   

20.
A nested polymerase chain reaction (PCR) assay was developed for the detection of bovine herpesvirus 1 (BHV-1) in bovine semen and compared with the virus isolation method. When extended semen, commonly used in the bovine artificial insemination industry, was inoculated with BHV-1, the PCR assay detected BHV-1 DNA in semen inoculated at 0.25-2.5 TCID50 per 0.5 mL. In contrast, the lower limit of detection for virus isolation was 250 TCID50 of BHV-1 inoculated in 0.5 mL of extended semen. These methods were also used to detect BHV-1 in the semen of four bulls which were experimentally infected with BHV-1. All infected bulls demonstrated balanitis at 3 d post-inoculation (DPI) and severe balanoposthitis at 4 DPI. BHV-1 was detected in raw semen by virus isolation and PCR at 2 DPI, before balanitis was evident. For virus isolation, the last day that BHV-1 was detected during primary infection was 7 DPI for two bulls and 9 and 11 DPI for the other two bulls. In contrast, PCR detected BHV-1 in the bulls' semen until 14 or 18 DPI. For individual animals, PCR detected BHV-1 during primary infection for at least 1-10 d longer than virus isolation. Reactivation of BHV-1 from latency without the presence of visible lesions was promoted twice by two series of 5 d dexamethasone injections. For the first series of dexamethasone treatments, a positive virus isolation result was obtained on the 5th d of treatment for only one bull. In contrast, two bulls demonstrated evidence of viral reactivation on this day by PCR. All bulls shed BHV-1 in semen on d 4 after dexamethasone treatment, as evidenced by positive virus isolation and PCR results. One bull was still PCR positive 13 d later. For the second series of dexamethasone treatments, a small amount of virus was isolated from semen collected on d 3 or 4 after treatment for two bulls but not from the other two bulls. In contrast, semen samples from all bulls were PCR positive for either or both of these 2 d. In total, from 80 semen samples, 45 were PCR positive and 26 were virus isolation positive. Thus, the PCR assay detected BHV-1 shedding in bulls earlier, more often, and for a longer duration, than did the virus isolation method.  相似文献   

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