The effect of route and dosage of immunization on the serological response to a Pasteurella haemolytica and Haemophilus somnus vaccine in feedlot calves

The effect of route and dosage of administration on the serological response to a vaccine containing genetically attenuated leukotoxin of Pasteurella haemolytica combined with bacterial extracts of P. haemolytica and Haemophilus somnus (Somnu-Star Ph, Biostar Inc., Saskatoon, Saskatchewan) was evaluated in a controlled field trial in 301 feedlot calves. Vaccination of calves on arrival at the feedlot with Somnu-Star Ph significantly (p < 0.05) increased P. haemolytica and H. somnus serum antibody titers and reduced bovine respiratory disease (BRD) morbidity. A single subcutaneous vaccination with Somnu-Star Ph was as effective in stimulating a humoral antibody response and in reducing BRD morbidity as double vaccination by the intramuscular or the subcutaneous route. Furthermore, there were no swellings or adverse reactions observed with either subcutaneous or intramuscular administration of Somnu-Star Ph.

These results suggest that feedlot calves can be immunized subcutaneously once on arrival with Somnu-Star Ph. Double vaccination was of no added value in this trial, because the majority of BRD morbidity occurred prior to revaccination fourteen days postarrival. Additional larger-sized field trials are needed to monitor the duration of immunity following vaccination and to test the effect of route and dosage of vaccination on mortality.

     

Immunogenicity of a soluble antigen againstPasteurella haemolytica-associated pneumonia in calves

Three experiments were performed to evaluate the immunogenic potency of a soluble fraction ofPasteurella haemolytica against pneumonic pasteurellosis in calves. A soluble antigen was extracted by a 2.5% saline solution fromP.haemolytica. Weaned Holstein bull calves, seronegative for infectious bovine rhinotracheitis virus (IBRV) and the pasteurella antigen, were vaccinated either by repeated subcutaneous (SC) vaccination, or by exposure 3 times to the aerosol ofP.haemolytica antigen. Challenge exposure to aerosol ofP.haemolytica was preceded by infection with IBRV, or in experiments 2 and 3, the virus exposures were combined with a stress treatment. The lung lesions were examined at necropsy 3 to 8 days post infection. In the first experiment, all the vaccinated calves produced specific antibody response to the pasteurella antigen, and none of the calves including controls showed significant lesions in the lung. In the second experiment 2 aerogenically vaccinated calves had no lesions. One of the two SC-vaccinated calves had mild consolidated lesions. Two control calves, one of which died 3 days following the challenge, developed severe fibrinous pneumonia with consolidation of 50% or more of the lung surfaces.P.haemolytica was isolated only from the 2 control animals. In the third experiment, 2 of the 3 control calves developed moderate to severe consolidation, butP.haemolytica was isolated only from one of them. Two of the three aerosol-vaccinated calves also developed significant lesions and one of them yielded the bacteria from the lung. Three SC-vaccinated calves had slight lesions and the organism was not isolated from their lungs. The results did not consistently indicate an immunogenic potential of the soluble antigen againstP.haemolytica-related pneumonia. The effect of stress on the pathogenesis of bovine viral penumonia and correlation between pneumonic lesions and antibacterial resistancein situ are discussed.     

Failure of a Subunit Bovine Herpesvirus 1 Vaccine to Protect Against Experimental Respiratory Disease in Calves

In two experiments in which 31 calves were used, a bovine herpesvirus 1 subunit vaccine previously shown to elicit a strong immunological response in adult cattle failed to do so in younger animals and failed to protect against pneumonia caused by sequential exposure to virulent bovine herpesvirus 1 and Pasteurella haemolytica aerosols. One of the experimental groups had been previously inoculated with a live commercial vaccine but even this failed to elicit a strong immunological response. These results indicate that the calves were in a refractory state when immunized and may explain why similar vaccine failures occur in the field.     

A Quantitative Flurometric Assay for the Measurement of Antibody to Pasteurella haemolytica in Cattle

A rapid, simple fluorometric method is described for measuring antibody to Pasteurella haemolytica in sera of cattle. Various antigen preparations were compared for the test including live, formalin-killed and phenol-killed P. haemolytica. A preparation composed of formalin-killed organisms from a 22 hour culture gave consistent results and was used in the studies. The test was reproduciable with percent coefficients of variation for fluorescent signal unit values on ten or more replicate samples ranging from 5.7 to 28.0. Sera from calves vaccinated by aerosol exposure to live P. haemolytica had up to a five-fold increase in antibody titer as measured by the flurometric method test during a 21 day period. Fluorometric method titers were comparable to those obtained by the indirect bacterial agglutination test. There was no seroconversion to P. haemolytica in calves vaccinated by aerosol exposure of P. multocida. The major advantages of the fluorometric method test over conventional methods are that the assay does not require serial dilutions of serum samples and thus limits time and effort to determine antibody titers.     

The immune response of goats vaccinated with low and high doses of Brucella melitensis Rev 1

The serological response, lymphocyte reactivity, and dermal hypersensitivity reactions of goats vaccinated with high and low doses of $\text{Brucella melitensis}$ Rev 1 organisms to Brucella antigens were studied. Antibodies to soluble antigen A2 were detectable by immunoelectrophoresis (IE), appeared later than agglutinating antibodies but disappeared faster in most vaccinated animals. Anti-A2 antibodies appeared earlier in goats which received the high dose. Antibodies to polysaccharide B antigen were not detected. Lymphocytes reactive to Brucella antigens in lymphocyte transformation assays appeared at variable times after vaccination. In contrast to the humoral response to antigen A2, the appearance of circulating, reactive lymphocytes was not dependent on vaccine doses. All vaccinated animals demonstrated dermal hypersensitivity reactions to one of the antigenic extracts. Skin reactions peaked at 24 hrs post inoculation. The reactions were elicited when all but one goat had undetectable anti-A2 antibodies and no circulating, reactive lymphocytes as measured in whole blood lymphocyte transformation assay.     

Immunoglobulin M-specific enzyme-linked immunosorbent assay for serodiagnosis of bovine respiratory syncytial virus infections

An antibody-capture enzyme-linked immunosorbent assay (ELISA) for detection of immunoglobulin (Ig) M antibodies to bovine respiratory syncytial virus (BRSV) in cattle was developed. Monoclonal antibody to bovine IgM was used as the catching antibody. The IgM-ELISA was used, as well as a BRSV-specific IgG ELISA to determine the kinetics of IgM and IgG antibody responses to BRSV infections in cattle. High IgM and IgG antibody titers developed after naturally occurring or induced BRSV infection of calves (6 to 7 months old). Induced infection resulted in an IgM response that was first detectable at postinoculation day (PID) 11 reached a maximum at PID 13, and became undetectable again about PID 28. An IgG response also was detected by PID 11. However, a maximum response was not reached before PID 23, and titers remained high (until PID 80). In naturally occurring infection, IgM and IgG responses in calves were observed in the acute phase of epizootics of respiratory tract disease. Patterns of IgM and IgG response curves were similar to those observed in experimentally infected calves. The involvement of BRSV in an epizootic of respiratory tract disease in 8 calves (2 to 3 weeks old) was demonstrated by the detection of BRSV in several lung lavage samples. All calves had existing IgG antibodies to BRSV which were interpreted to be maternally derived. None of the calves responded with an increase in IgG antibody titer. However, a weak but distinct BRSV IgM antibody response occurred in 6 calves.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevention of bovine respiratory syncytial virus infection and clinical disease by vaccination

A double blind field trial was carried out with a live attenuated bovine respiratory syncytial virus vaccine. The trial involved 530 calves, two to 10 months old, on 27 dairy farms, where respiratory problems due to bovine respiratory syncytial virus infections had been observed during the preceding year. In 17 herds either all calves were vaccinated (nine groups) or all calves received a placebo (eight groups). In 10 herds half the number of calves were vaccinated and the other half kept as non-vaccinated controls. Calves were vaccinated intramuscularly twice with an interval of four to five weeks. These groups were under regular clinical observation and animals were tested periodically for antibodies to bovine respiratory syncytial virus and parainfluenza type 3 virus. Serological examination indicated that no bovine respiratory syncytial virus infection had occurred prior to the first vaccination in August. Vaccination did not cause adverse reactions. Low concentrations of neutralising and complement fixing antibodies were induced by vaccination and a sharp increase of antibody titres was observed after natural infection of vaccinated animals. Infections with bovine respiratory syncytial virus occurred in six out of eight non-vaccinated groups, in nine out of 10 partly vaccinated groups and in only two out of nine completely vaccinated groups. Virus infection in completely vaccinated groups was significantly reduced compared with partly vaccinated and non-vaccinated groups. The incidence of bovine respiratory syncytial virus lower respiratory disease was significantly reduced in completely vaccinated groups compared to non-vaccinated groups. Generally only mild signs of upper respiratory disease were present in completely vaccinated groups after bovine respiratory syncytial virus infection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of bovine antibody responses to haemorrhagic septicaemia vaccine

ELISA and immunoblotting techniques were used to examine the humoral immune response to Pasteurella multocida, in bovine sera from Indonesia and Malaysia. Elevated levels of antibody to a crude lipopolysaccharide preparation were found in vaccinated animals. In addition to the response to lipopolysaccharide, antibodies from the vaccinated cattle strongly labelled five to six of the 40 protein bands in this organism.     

Lack of reactivity of sera from Theileriaparva-infected and recovered cattle against cell membrane antigens of Theileria parva transformed cell lines

Sera from $\text{Theileria}$$\text{parva}$ infected, recovered and rechallenged cattle were tested in complement-dependent cytotoxicity, membrane immunofluorescence and antibody-dependent cellular cytotoxicity assays for the presence of antibodies against cell membrane antigens of $\text{T}$. $\text{parva}$ transformed cell lines.In the complement-dependent antibody-mediated cytotoxicity assay, sera from lethally infected animals were negative. Some recovered cattle showed a positive reaction, but such reactions were also observed when an eland cell line infected with $\text{T}$. $\text{taurotragi}$, and bovine lymphoblastoid cells were used as targets. Reaction was less against Ig-negative peripheral blood lymphocytes.Evidence is presented that these reactions could be evoked by attachment of immune complexes to Fc-receptors. It is concluded that cattle exposed to $\text{T}$. $\text{parva}$ infection do not develop antibodies against specific $\text{T}$. $\text{parva}$ (or $\text{T}$. $\text{parva}$-induced) cell surface antigens.     

Safety and efficacy testing of a novel multivalent bovine bacterial respiratory vaccine composed of five bacterins and two immunogens

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.     

Immune response to Neospora caninum in naturally infected heifers and heifers vaccinated with inactivated antigen during the second trimester of gestation

The objective of this study was to compare the immune response to Neospora caninum in naturally infected heifers and heifers inoculated with a killed whole N. caninum tachyzoite preparation during the second trimester of gestation. Nine Holstein heifers were used in this study; three naturally infected heifers were born from seropositive dams, and six seronegative heifers were born from seronegative dams. Four seronegative heifers were subcutaneously vaccinated with a killed whole N. caninum tachyzoite preparation at weeks 13, 15 and 17 of gestation. A killed whole N. caninum tachyzoite preparation containing 45 mg of protein/5 ml dose was formulated with 70% of mineral oil adjuvant (13% consisting of Arlacel C, 85% Marcol 52 and 2% Tween-80). Similarly, two seronegative heifers (negative controls) were inoculated with mock-infected bovine monocytes in oil adjuvant. Humoral immune responses were tested by using an indirect fluorescent antibody test (IFAT) and an indirect enzyme-linked immunosorbent assay (ELISA) for detecting isotype specific antibodies. Cellular immune responses were assessed by lymphocyte proliferation test (LPT) and IFN-gamma production. N. caninum-specific antibody responses increased in immunized cattle by week 15 of gestation (mean reciprocal antibody titers 450+/-252), peaked at week 23 (mean 16,000+/-6400). Maximum antibody response in naturally infected heifers was observed at week 19 of gestation (mean: 3467+/-2810). Mean serum IFAT titers were significantly higher in immunized heifers compared with those in naturally infected heifers from weeks 17 to 25 (P < 0.05). Analysis of isotype specific antibodies in naturally infected heifers revealed a predominant IgG1 response in one heifer and a predominant IgG2 response in the other two. Similar titers of IgG1 and IgG2 occurred in immunized heifers. Control heifers remained seronegative throughout the study by IFAT and ELISA. Significant antigen-specific proliferation responses were only detected in naturally infected heifers in week 19 of gestation. Peripheral mononuclear blood cells (PMBC) from immunized animals produced IFN-gamma in similar concentrations to those of infected animals (P > 0.05). No abortion was seen in any experimental group; however, one calf from a vaccinated heifer died due to dystocia. All calves from vaccinated and control heifers were seronegative by IFAT at 6 months of age; in contrast, calves born from naturally infected heifers remained seropositive with titers > or = 200. Killed vaccine induced similar immune responses to those found in chronically, naturally infected cattle which did not abort; however, different immune pathways may be followed in vaccinated and natural infected heifers with differences in degree of protective immunity.     

The influence of transport stress on the humoral immunological response of calves induced by Mannheimia haemolytica leukotoxin

In the contemporary systems of cattle production, transport stress is the most essential poly-etiological factor responsible for inducing unfavourable reactions in the animals. The main reason for this phenomenon is the immunosuppressive effect of steroid hormones on cellular and humoral protective mechanisms. The purpose of the present study was to establish the relationship between the cortisol concentration as an indicator of the stress reaction occuring directly after the transportation of calves and the specific humoral immune response to the leukotoxin (Lkt) antigen produced by the M. haemolytica strain. The experiment was carried out on 19 clinically healthy calves, weighing about 100 kg and transported by track for about 2 hours. After the delivery of the animals for feeding to the traditional cattle-house, the calves were immunized s.c.: group I with 1 ml Lkt (in conc.--10 microg/ml) with 1 ml of adjuvant on the 1st and 14th day after the transportation, group II with the same Lkt doses on the 3rd and 16th day after the transportation. The animals of the control group were vaccinated on the 1st and 14th day after the transportation with the twice diluted adjuvant. In examined sera the cortisol concentrations and the level of Lkt antibodies were measured by ELISA test. The cytotoxin neutralizing (CN) antibody level (cytotoxity assay) was determined with a simple visual assay. The study revealed, significant differences (P < or = 0.01) in serum cortisol levels between the control and experimental animals. The analysis of the absorbance of the sera in both groups immunized with Lkt showed substantial differences (P < or = 0.05) from the 6th through to 22nd day of the experiment compared with the control group. The analysis of the results of CN antibody titers showed no differences between the sera from group I and II. Based on the results obtained in this experiment it can be assumed, that a short transportation stress has no important influence on the level of specific humoral anti-Lkt response.     

Influence of Immunization Procedures on Upper Respiratory Tract Immunity in Cattle

Aspects of respiratory tract immunity have been investigated in the bovine species. Using Past. hemolytica type I as the antigen for this model the relationship of nasal and serum antibody production to the route of vaccination and type of vaccine was investigated in a series of 15 dairy calves from two to four months of age. Experimental results indicated that an aerosol vaccination with live Past. hemolytica resulted in a significant nasal antibody response while parenterally vaccinated gave calves with equivalent serum titers had no significant nasal antibody response.     

Characterization and identification of a bovine respiratory syncytial virus isolated from young calves.

Two identical viruses designated 371 and 375 were recovered from nasal secretions of 2 of 7 calves in a beef cow-calf herd in which calves (45 to 105 days of age) had signs of acute respiratory tract disease. The cytopathic, morphologic and physico-chemical characteristics of the isolates were those of bovine respiratory syncytial virus. Although a humoral antibody response to bovine respiratory syncytial virus was not observed, it was concluded that this virus probably had a part in the respiratory tract disease in these calves.     

Antibody response of calves to immunoaffinity-purified bovine respiratory syncytial virus VP70 after vaccination and challenge exposure.

Immunoaffinity-purified bovine respiratory syncytial virus (BRSV) fusion (F) protein elicited anti-BRSV-specific antibody responses in BRSV-seronegative calves. After primary vaccination, all calves seroconverted to BRSV as determined by the virus neutralization (VN) test and developed anti-F protein antibodies detectable by protein immunoblot analyses. Subsequent vaccinations induced greater than twofold increase in VN titer in 3 of 9 (33%) calves, and 1 calf became VN-negative, but still had nonneutralizing antibody detectable by protein immunoblot analysis. This calf remained seronegative after challenge exposure. Two groups of calves were vaccinated IM with immunoaffinity-purified BRSV F protein. Each dose was 2 ml containing 20 micrograms of purified F protein. Freund's adjuvants were used for all vaccinations, with Freund's complete adjuvant used for the primary vaccination and Freund's incomplete adjuvant for subsequent vaccinations. The vaccine was administered to both groups at weeks 0 and 3; the first group received a third vaccination at weeks 21. Group-1 and -2 vaccinated calves and non-vaccinated contact controls were intranasally aerosol challenge-exposed with low cell culture-passage BRSV on weeks 22 and 9, respectively. Eight of 9 vaccinated calves did not develop a humoral anamnestic response following challenge exposure, as demonstrated by VN test and protein immunoblot analyses. Calf 14 from group 1 which had a 1:2 VN antibody titer prior to vaccination, was the only calf that developed an anamnestic response.(ABSTRACT TRUNCATED AT 250 WORDS)     

Bovine babesiosis: The immunization of cattle with fractions of erythrocytes infected with Babesia bovis (syn B. argentina)

Soluble antigen which protected susceptible cattle against challenge with $\text{Babesia bovis}$ was extracted from $\text{B. bovis}$-infected erythrocytes by sonic disintegration and separation of the soluble from the insoluble matter by ultracentrifugation. The material was then fractionated by the precipitation of fibrinogen-like proteins. The precipitate contained the babesial antigens that were located on the stroma of the infected erythrocytes. Antigen originally located on the parasite remained in solution. Both fractions conferred protection on splenectomized calves against challenge with $\text{B. bovis}$. However, the fraction containing the parasite antigens appeared to have more potential for development as a killed vaccine because it was not heavily contaminated with antigenic material from bovine erythrocytes.     

A competitive enzyme immunoassay for the detection of bovine antibodies to Brucella abortus using monoclonal antibodies

A competitive enzyme immunoassay (EIA) for the detection of circulating bovine antibodies to Brucella abortus has been developed using horseradish peroxidase conjugated monoclonal antibodies (MAb) raised against B. abortus cell surface antigens. Antibodies present in the serum of either vaccinated or infected cattle can apparently displace the conjugated MAb from the lipopolysaccharide antigen (LPS) in a quantitatively different manner allowing an assessment of immune status of the animal. The results from a panel of sera from animals with a known status of vaccination or infection indicated that the test was more selective in the detection and discrimination of infected from uninfected or immunized animals, than conventional complement fixation, agglutination or indirect enzyme immunoassay procedures.     

Efficacy of an inactivated,recombinant bovine herpesvirus type 5 (BoHV-5) vaccine

Bovine herpesvirus type 5 (BoHV-5) is the causative agent of bovine herpetic encephalitis. In countries where BoHV-5 is prevalent, attempts to vaccinate cattle to prevent clinical signs from BoHV-5-induced disease have relied essentially on vaccination with BoHV-1 vaccines. However, such practice has been shown not to confer full protection to BoHV-5 challenge. In the present study, an inactivated, oil adjuvanted vaccine prepared with a recombinant BoHV-5 from which the genes coding for glycoprotein I (gI), glycoprotein E (gE) and membrane protein US9 were deleted (BoHV-5 gI/gE/US9⁻), was evaluated in cattle in a vaccination/challenge experiment. The vaccine was prepared from a virus suspension containing a pre-inactivation antigenic mass equivalent to 10^7.69 TCID₅₀/dose. Three mL of the inactivated vaccine were administered subcutaneously to eight calves serologically negative for BoHV-5 (vaccinated group). Four other calves were mock-vaccinated with an equivalent preparation without viral antigens (control group). Both groups were boostered 28 days later. Neither clinical signs of disease nor adverse effects were observed during or after vaccination. A specific serological response, revealed by the development of neutralizing antibodies, was detected in all vaccinated animals after the first dose of vaccine, whereas control animals remained seronegative. Calves were subsequently challenged on day 77 post-vaccination (pv) with 10^9.25 TCID₅₀ of the wild-type BoHV-5 (parental strain EVI 88/95). After challenge, vaccinated cattle displayed mild signs of respiratory disease, whereas the control group developed respiratory disease and severe encephalitis, which led to culling of 2/4 calves. Searches for viral DNA in the central nervous system (CNS) of vaccinated calves indicated that wild-type BoHV-5 did not replicate, whereas in CNS tissues of calves on the control group, viral DNA was widely distributed. BoHV-5 shedding in nasal secretions was significantly lower in vaccinated calves than in the control group on days 2, 3, 4 and 6 post-challenge (pc). In addition, the duration of virus shedding was significantly shorter in the vaccinated (7 days) than in controls (12 days). Attempts to reactivate latent infection by administration of dexamethasone at 147 days pv led to recrudescence of mild signs of respiratory disease in both vaccinated and control groups. Infectious virus shedding in nasal secretions was detected at reactivation and was significantly lower in vaccinated cattle than in controls on days 11–13 post-reactivation (pr). It is concluded that the inactivated vaccine prepared with the BoHV-5 gI/gE/US9⁻ recombinant was capable of conferring protection to encephalitis when vaccinated cattle were challenged with a large infectious dose of the parental wild type BoHV-5. However, it did not avoid the establishment of latency nor impeded dexamethasone-induced reactivation of the virus, despite a significant reduction in virus shedding after challenge and at reactivation on vaccinated calves.     

A field trial to evaluate the efficacy of a commercial Pasteurella haemolytica bacterial extract in preventing bovine respiratory disease

A double blind, random, controlled field trial was conducted to ascertain the efficacy of a Pasteurella haemolytica bacterial extract (Presponse, Langford Inc., Guelph, Ontario) in the prevention of bovine respiratory disease and/or its effects. Calves from 13 ranches (n = 1140 calves) were assigned to one of four groups, namely: vaccinated at the ranch three weeks prior to shipping to the feedlot; vaccinated only on arrival at the feedlot; vaccinated at both locations; or not vaccinated at either location. Four replicates of auction calves (n = 731) were also assigned to either receive or not receive the vaccine on arrival at the feedlot.

The vaccine did not effect a change in morbidity rates or weight gain. Total mortality rates were increased significantly, and mortality rates from respiratory disease tended to be increased in ranch calves that were vaccinated with Presponse at the ranch. In auction calves, the relapse rates were significantly lower in vaccinated calves. There was a tendency towards a reduction of respiratory disease-related mortality, however there appeared to be no sparing against death from fibrinous pneumonia in auction calves.