Immunogenicity of potassium thiocyanate extracted and electrofocused Pasteurella multocida X-73I antigens in chickens and mice

The immunogenicity of antigenic fractions obtained by the extraction of Pasteurella multocida strain X-73 (serotype 1) with potassium thiocyanate (KSCN) was determined in chickens and mice. The initial KSCN extract was centrifuged at 105 000 X g, and the antigens were separated into a particulate fraction (40p) and a soluble supernatant fraction (40s). The ultracentrifuged fractions were further resolved by preparative electrofocusing. The 40p fraction was resolved into two subgroups having isoelectric points of 3.5-3.9 and 5.5-6.0; the 40s fraction was resolved into five subgroups ranging in isoelectric points from 4.4 to 9.0. The 40p fractions were antigenically similar and contained lipopolysaccharide (LPS) and protein. The 40s fractions were antigenically distinct from the 40p fractions and from each other; they contained proteins and polysaccharides but no LPS. The 40p antigens were strongly immunogenic in mice and chickens, whereas the 40s antigens were weakly immunogenic in chickens and not immunogenic in mice. The incorporation of Freund's complete adjuvant increased the immunogenicity of the 40s antigens in chickens. The 40p antigens induced greater frequencies of serological responses in chickens than the 40s antigens as detected by counterimmunoelectrophoresis and immunodiffusion. This suggested that the increased protection associated with the 40p antigens may have been the result of better antibody response. The toxicity of all the fractions was evaluated by determination of lethality for 10-day-old chicken embryos because of the sensitivity and reliability of the test. The 40p fraction had an LD50 = 0.38 micrograms, and the 40s fraction had an LD50 = 2.5 micrograms. Since the 40s fraction contained no detectable LPS, it is likely that two toxins are present, one which contains LPS and one which does not.

Lysates of turkey-grown Pasteurella multocida: partial solubilization of the cross-protection factor(s)

A lysate of turkey-grown Pasteurella multocida was treated to determine the nature of a cross-protection factor (CPF). Complete lysate was treated with proteolytic enzymes and mild heat. Cross protection was not induced with pepsin-treated lysate, but 50% cross protection was induced with trypsin-treated lysate and 100% cross protection was induced in turkeys vaccinated with lysate heated at 56 C for 1 hour. Complete lysate was also fractionated by differential and sucrose density gradient centrifugation. After the lysate was centrifuged for 1 hour at 100,000 x g, the CPF was found in the supernatant and pellet fractions, indicating that the CPF was dispersed throughout; 84% of the lysate protein was in the supernatant and 14.7% of the protein in the pellet. After sucrose density gradient centrifugation, 100% cross protection was induced with the top and bottom gradient fractions and 60% with the middle fraction. Although the differential centrifugation pellet and bottom sucrose gradient fraction had protein that was disproportionately small when compared with the soluble portions of the whole lysate, they had the CPF equal in immunizing capacity.

Antibody titers to Pasteurella haemolytica A1 in Ontario beef cattle

Indirect bacterial agglutination titers to Pasteurella haemolytica A1 were determined in serum, thoracic, pericardial, or peritoneal fluid from cattle necropsied as part of the Bruce County Beef Project in 1979-80 and 1980-81. Antibody titers were also assayed in serum from 84 calves on entry to feedlots in the fall of 1979. Titers on entry were low compared to antibody levels at necropsy. Cattle which died with pneumonia, in particular those dying of fibrinous pneumonia (shipping fever), had lower levels of antibody to P. haemolytica than did those dying of other causes.

Bovine herpesvirus-1 vaccination against experimental bovine herpesvirus-1 and Pasteurella haemolytica respiratory tract infection: onset of protection

The onset of protection offered by intranasal vaccination with attenuated bovine herpesvirus-1 (BHV-1) was studied in 18 calves given a virulent BHV-1 aerosol challenge inoculum and an aerosol challenge exposure to Pasteurella haemolytica. Calves challenge exposed with virus 3, 7, 11, 15, or 19 days after vaccination and challenge exposed 4 days later with Pasteurella haemolytica did not develop viral-bacterial pneumonia, whereas 2 of 3 control calves died of fibrinous bronchopneumonia 40 and 60 hours after the bacterial aerosol and the 3rd control calf had similar lesions. All vaccinated and control calves had detectable amounts of interferon at the time of viral challenge exposure. Protection was observed before detection of neutralizing antibodies to BHV-1 in nasal secretions or in serum. Protection was therefore present from day 3 through day 19 after vaccination, but the mechanism could not be explained completely by neutralizing antibody or interferon.

Comparisons of the serologic response of chickens to Pasteurella multocida and its lipopolysaccharide

Chickens were inoculated with serotype 3 Pasteurella multocida cells or purified lipopolysaccharide (LPS), and their serologic responses to LPS and heat-stable antigens of 16 serotypes were compared. Chickens inoculated with cells or LPS had antibodies against LPS as determined by indirect hemagglutination tests; titers were highest 2-4 weeks after the initial inoculation. Sera from chickens inoculated with cells reacted with unheated and heated cell antigen in a tube-agglutination test. Sera from chickens inoculated with LPS reacted only with heated cell antigen in the tube-agglutination test. Nonspecific reactions with heat-stable antigens of other serotypes occurred in the gel-diffusion-precipitin test with sera from chickens inoculated with cells but not with sera from chickens inoculated with LPS. Antisera prepared against LPS could be used for serotyping field isolates of P. multocida.

Proliferative responses of rabbit lymphocytes to Pasteurella multocida decrease with prolonged immunization

Peripheral blood and splenic lymphocytes from rabbits immunized with Pasteurella multocida by various schedules were stimulated to undergo blast transformation in vitro in response to this antigen. Repeated immunizations suppressed this response.

Serological types of Pasteurella multocida isolated from turkeys and chickens in Canada

Outbreaks of fowl cholera continue to plague the Canadian poultry industry despite widespread immunization against the causative agent, Pasteurella multocida. Fowl cholera bacterins currently employed by domestic poultry growers contain three serological types, namely, serotypes 1, 3, and 4. In this study a total of 84 strains of P. multocida were isolated in Canada from outbreaks of fowl cholera in turkeys and chickens. Serotyping was accomplished using the gel diffusion precipitin test. Based on the gel diffusion precipitation patterns, 27 serotypes containing one to six antigenic determinants were recognized. The most prevalent serotype both in turkeys and chickens appeared to be type 3. Significantly, greater than 20% of P. multocida isolates failed to react with antisera raised against serotypes 1, 3, and 4.

Purification of a protective antigen from a saline extract of Pasteurella multocida

It has been shown previously that soluble material extracted from Pasteurella multocida P-1059 by a 2.5% NaCl solution protects turkeys from generalized septicemia at a subsequent challenge exposure to the organism. In the present study, a protective antigen was purified from the crude soluble material by chromatographic methods. Four protein peaks were obtained by gel filtration with Sephadex G-200. The protective antigen was detected only in the first peak fraction, which contained a substantial amount of carbohydrate. The peak 1 fraction was adsorbed onto DEAE-cellulose and eluted by a linear gradient of NaCl. Fractions corresponding to a single protein peak were pooled and passed through an immunoadsorbent column to remove any possible serum component originating from the growth medium. The purified antigen had a carbohydrate/protein ratio of 1.5 and formed a single precipitin line with rabbit antiserum against the crude material in gel diffusion and immunoelectrophoresis analyses. The antigen produced antibodies in rabbits and turkeys which formed a single precipitin line against the crude material. Upon sodium dodecyl sulfate-polyacryl-amide gel electrophoresis, the purified antigen showed three protein bands, corresponding to molecular weights of 44,000, 31,000, and 25,000, and one carbohydrate band. The carbohydrate band did not correspond to any of the three protein bands. Upon isoelectric focusing gel analysis, the purified antigen showed two bands (pI = 3.5 to 4.0 and 4.5 to 5.5), but the two bands were antigenically identical by isoelectric focusing crossed immunoelectrophoresis. The 50% protective dose of the purified antigen was between 10 and 50 mug of protein in trials where two doses were given at 14-day intervals to 10- to 20-week-old turkeys.

A comparison of immunoferritin, immuno-enzyme and gold-labelled protein A methods for the localization of capsular antigen on frozen thin sections of the bacterium, Pasteurella haemolytica

The staphylococcal protein A-gold method was found to be superior to the enzyme-or ferritin-linked antibody techniques for locating capsular antigens on cryosections of Pasteurella haemolytica, and its sensitivity was similar to the enzyme-linked antibody method. The sensitivity of conventionally fixed and embedded material and cryosections of heavily fixed, lightly fixed and unfixed material were shown to be similar under routine laboratory conditions.

Cross-protection by a chemically altered vaccinal strain of Pasteurella multocida in mice and hamsters

A chemically altered type A strain of Pasteurella multocida was used to vaccinate mice and hamsters. The vaccinated animals were challenge exposed with type A, B, and E isolated of P multocida. A degree of protection was afforded the vaccinated animals against homologous and heterologous challenge-exposure strains.

Aerosol vaccination of calves with pasteurella haemolytica against experimental respiratory disease

Three experiments were conducted on calves in which the efficacy of vaccination with live Pasteurella haemolytica in aerosol was tested by challenge with sequential aerosol exposure to bovine herpesvirus 1 and P. haemolytica. Neither single nor multiple aerosol vaccinations protected against the experimental disease. Macroscopically recognizable rhinitis, tonsillitis, tracheitis and pneumonia occurred in both controls and vaccinates. In one experiment as many as three aerosol vaccinations with live P. haemolytica for up to 20 minutes failed to elicit clinical signs in exposed calves. Pasteurella haemolytica was isolated less frequently from tissues of vaccinated calves than from those of nonvaccinated calves. Pasteurella haemolytica was isolated from deep nasal swabs of 4/14 vaccinated calves five and six days after viral exposure. It was concluded that although bovine herpesvirus 1 vaccination has been shown previously to prevent the experimental disease produced by bovine herpesvirus 1-P. haemolytica, live P. haemolytica vaccination by aerosol will not provide the same protection.

Effect on the incidence of atrophic rhinitis of vaccination of sows with a vaccine containing Pasteurella multocida toxin

Combined experimental infections with Bordetella bronchiseptica and either a toxigenic or a non-toxic strain of P. multocida were carried out in newborn specific pathogen free piglets born to 25 sows. Pigs inoculated with B. bronchiseptica and toxin-producing P. multocida developed severe progressive atrophic rhinitis corresponding to the natural disease. The effect of vaccination of sows with a toxin-containing P. multocida vaccine on the incidence of nasal lesions in the offspring was studied.

Purification and partial characterization of a macrophage cytotoxin from Pasteurella haemolytica

A protein from Pasteurella haemolytica that was highly immunogenic and toxic toward bovine alveolar macrophages was partially purified. When isolated from culture supernatants of P haemolytica serotype 1 or serotype 6, the protein reacted on Ouchterlony immunodiffusion tests with antisera from 12 serotypes of P haemolytica, but did not cross-react with antisera to serotypes of P multocida. This indicated that the protein may be specific for P haemolytica. Bacteria were grown in dialysis culture in a brain-heart infusion and calf-serum growth medium. The protein was isolated from the medium by ultrafiltration and size-exclusion chromatography and has a molecular weight of approximately 150,000 daltons. The protein, which is highly immunogenic and has the characteristics of a virulence factor, is common to all serotypes of P haemolytica, and may be an effective agent for immunization against P haemolytica in cattle.

Indirect hemagglutination test that uses glutaraldehyde-fixed sheep erythrocytes sensitized with extract antigens for detection of Pasteurella antibody

Glutaraldehyde-fixed sheep erythrocytes (GA-SRBC) were used in the indirect hemagglutination test for the detection of Pasteurella antibody. GA-SRBC were stable for at least 6 months. Heat extract or potassium thiocyanate extract antigens of Pasteurella strains could be adsorbed onto GA-SRBC or tanned GA-SRBC, respectively. The indirect hemagglutination test reaction was capsular group specific with heat extract antigen-sensitized GA-SRBC but not potassium thiocyanate extract antigen-sensitized tanned GA-SRBC.

Purification of Pasteurella multocida antigens by ultracentrifugation and isoelectrofocusing

A procedure was developed to purify Pasteurella multocida X-731 antigens extracted by potassium thiocyanate. The crude extract was centrifuged at 105 000 x g; the antigens were then separated into a particulate (40p) fraction and a soluble (40s) fraction consisting of proteins and polysaccharides. These fractions were antigenically different. The ultracentrifuged antigens were resolved further by preparative isoelectrofocusing. The 40p antigens focused in a pH range of 3.0 to 6.0; distinctive proteins focused at pH's of 3.5, 3.6, and 3.8. The electrofocused 40p antigens were antigenically similar. The 40s antigens were initially electrofocused in a broad pH range and were found within a pH range of 4.6 to 9.0. The process was repeated with a narrower pH range and antigens that were focused in a narrower pH range could be separated and unique antigenic activities identified. Specific antigens from defined pH ranges were pooled and examined further by immunoelectrophoresis, analytical electrofocusing, and sodium dodecyl sulphate--polyacrylamide gel electrophoresis.

Distribution of Pasteurella haemolytica and Pasteurella multocida in the bovine lung following vaccination and challenge exposure as an indicator of lung resistance

Experimental calves were vaccinated with virulent strains of Pasteurella haemolytica or Pasteurella multocida or with phosphate-buffered saline solution either by an aerosol method or by subcutaneous injection. Calves were subsequently challenge exposed by intrapulmonic inoculation of the homologous virulent Pasteurella species. Sections obtained from the resulting pulmonic lesion were stained, using a fluorescent antibody technique, to determine relative number, location, and integrity of the challenge organism. The resistance of the calf to challenge exposure, as determined by other factors, was compared with the capacity of the components of the lung to engulf or destroy pasteurellae. Calves vaccinated with an aerosol of the bacterium were most resistant to challenge exposure; most bacteria were engulfed or degraded by the phagocytic cells. Vaccination by subcutaneous injection was less effective in inducing resistance. Tissue sections from these calves contained many more extracellular intact bacteria and fewer intracellular intact or degraded bacteria than were seen in the sections of calves vaccinated by the aerosol method. The control calves were the least resistant; bacteria seen in tissue sections from these calves were numerous, predominantly extracellular, and intact. A group of nonvaccinated calves experimentally inoculated with infectious bovine rhinotracheitis virus 5 days before intrapulmonic challenge exposure with P haemolytica developed severe pulmonic lesions. The lesions were larger and more invasive and contained many more extracellular bacteria than did the lungs of calves in control groups. As in other nonvaccinated calves, there were few intracellular bacteria; however, unlike in other calves, the extracellular bacteria were seen in large numbers, particularly in alveolar lumens.

Experimental infection of lambs with bovine respiratory syncytial virus and Pasteurella haemolytica: immunofluorescent and electron microscopic studies

Colostrum-deprived lambs were inoculated transtracheally with respiratory syncytial virus (RSV), Pasteurella haemolytica, or RSV and P haemolytica. Multiple tissues were examined by immunofluorescence to localize viral and bacterial antigens, and lungs were examined by electron microscopy for cytopathologic changes. Using immunofluorescence, viral antigen was detected only in the respiratory tract, mainly in the bronchial and bronchiolar epithelium and in the alveolar wall. Lesser amounts of viral antigen were detected in the surface epithelium of the nasal turbinates and trachea. Bacterial antigen was not detected. Ultrastructurally, the lambs inoculated with P haemolytica or with RSV and P haemolytica had increased numbers of type II pneumocytes, necrotic epithelial cells, neutrophils, and macrophages and excessive cellular debris in multiple foci in the lungs. Bacterial were seen only infrequently; they were within phagocytic vacuoles of neutrophils and macrophages and were free within pulmonary septa. In lambs inoculated with RSV or with RSV and P haemolytica, cells in the epithelium were multinucleated. Viral buds were seen on cytoplasmic membranes of ciliated and nonciliated cells of bronchial and bronchiolar epithelium. Isolated epithelial cells were necrotic. Viral nucleoprotein was prevalent in a few alveoli, free or within vacuoles of phagocytic cells. Necrotic debris and phagocytic cells were more prominent in the alveoli of lambs inoculated with RSV and P haemolytica than in those of lambs inoculated with either agent alone.

Cytotoxic effect of Pasteurella haemolytica on bovine polymorphonuclear leukocytes and impaired production of chemotactic factors by Pasteurella haemolytica-infected alveolar macrophages

Pasteurella haemolytica exerted a cytotoxic effect on bovine polymorphonuclear neutrophil leukocytes. This effect was less than that seen with cultured alveolar macrophages or peripheral blood monocytes. When alveolar macrophages were cultured with Pasteurella haemolytica, macrophages produced less chemotactic factors for polymorphonuclear leukocytes than did noninfected controls. This effect was reversible, in that removal of the bacteria permitted remaining macrophages to elaborate more chemotactic factors than was seen in controls. The possible consequences of this impairment of function of alveolar macrophages are discussed.