Experimental pneumonia in rabbits inoculated with strains of Pasteurella multocida.

Domestic rabbits were inoculated with either a 3:A or 3:D serotype of Pasteurella multocida by aerosol, intravenous, or intratracheal inoculation. Different colony forming units of P. multocida were used. Animals which died or were killed after the 14 day observation period were examined macroscopically and microscopically for lesions in the lower respiratory tract. Pneumonic lesions were most consistently produced in rabbits inoculated intratracheally with serotype 3:A. Pulmonary and pleural lesions were observed in some animals inoculated intravenously with serotype 3:A. Lesions were minimal in rabbits inoculated with serotype 3:D. Of the three routes of inoculation evaluated, the intratracheal route appeared to be the best method to produce Pasteurella-associated lesions in the lower respiratory tract.

Pasteurella multocida infection in the domestic rabbit: immunization with a streptomycin-dependent mutant.

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

Characterization of Pasteurella multocida isolated from rabbits in Canada.

In a survey for the somatic and capsular serotypes of Pasteurella multocida present in domestic rabbits in Canada, but mainly in Ontario, samples were obtained from research facilities, commercial rabbitries and from abattoir and necropsy specimens. Sources of isolates were upper respiratory tract infections, localized bronchopneumonias , acute fibrinous pneumonias, abscesses and otitis media. Of 59 isolates obtained, 47.0% were type 12:A, 30.5% 3:D and 12.0% were 3:A. Less common types were 12(4):A, 12:D, 4(12):A and 3:untypable. Somatic group 3 was most commonly isolated from acute pneumonic disease, while serogroup 12:A was most commonly found in upper respiratory tract infections and in localized chronic bronchopneumonia. Two serotypes of P. multocida were isolated from four pneumonic lungs collected from abattoir specimens. Most isolates were susceptible to the commonly used antibiotics.

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.

Antigenic analysis if Pasteurella multocida (serotype 1) by crossed immunoelectrophoresis: characterization of whole cell associated antigens.

Crossed immunoelectrophoresis and other related quantitative immunoelectrophoresis techniques have been used to elucidate the antigenic complexity of a reference preparation of capsular extract, potassium thiocyanate extract, lipopolysaccharide, heat-stable antigens, and free endotoxin from Pasteurella multocida serotype 1. The reactions of these cellular fractions in crossed immunoelectrophoresis, with reference anti-whole cell immunoglobulins disclosed five antigens in the capsular extract, seven in the potassium thiocyanate extract, one to three in the lipopolysaccharide, three in the heat-stable antigens, and five in the free endotoxin. Comparison of these reference antigen-antibody systems, in crossed immunoelectrophoresis, with intermediate gel containing wither a reference anti-cell envelope or anticytoplasmic immunoglobulins not only revealed the presence of additional antigens but also gave insight into the probably cellular origins (i.e., cell surface, cell envelope, or cytoplasm) of various antigens unveiled by reference anti-whole cell immunoglobulins. Using the principle of tandem crossed immunoelectrophoresis and crossed-line immunoelectrophoresis the immunochemical relationships between the antigenic components of these reference antigen-antibody systems were established.

Antigenic analysis of Pasteurella multocida (serotype 1) by crossed immunoelectrophoresis: characterization of cytoplasmic and cell envelope associated antigens.

The application of crossed immunoelectrophoresis to the analysis of a reference cytoplasm and cell envelope preparation from Pasteurella multocida serotype 1 revealed antigenic complexity not previously found. At least 55 cytoplasmic and 19 cell envelope antigens were clearly distinguished. Variation of anticytoplasm immunoglobulin concentration was a major determining factor in resolving the maximum array of cytoplasmic antigens. The use of intermediate gel modification of crossed immunoelectrophoresis permitted the recognition of antibodies in the preimmune rabbit serum against a number of cytoplasmic antigens and a single cell envelope antigen. This technique also demonstrated that reference cytoplasm obtained by 105,000 x g centrifugation of sonically disrupted pasteurellae and repeatedly washed reference cell envelope preparation contained antigens of either origin in amounts sufficient to elicit antibody responses in the host. Antisera to whole cells in the intermediate gel indicated that formalin killed P. multocida were capable of eliciting immune responses to both reference systems.

Properties of a cold hemagglutin in associated with leptospiral hemolytic anemia of sheep.

The cold hemagglutinin which appears after leptospiral infection of sheep was isolated consistently from the plasma by absorption to autologous erythrocyte stroma at 4 C and subsequent elution at 25 C. Immunoelectrophoretic tests disclosed that the purified preparations consisted primarily of a single detectable component with the electrophoretic, positional, and antigenic characteristics of ovine immunoglobulin M. The properties of the cold hemagglutinin included a rapid sedimentation rate, elution in the leading peak from G-200 Sephadex, high anionic-binding capacity, and rapid electrophoretic mobility. Thus, these methods also supported the identification of the cold hemagglutinin as a homogeneous protein with properties like immunoglobulin M. The occurrence of the cold hemagglutinin after the phase of leptospiremia and concurrent to the onset of hemolytic anemia suggests that this antibody may play a significant role in the genesis of leptospiral acquired hemolytic anemia.