Safety and Protective Efficacy of Intramuscular Vaccination with a LivearoADerivative ofPasteurella multocidaB:2 against Experimental Hemorrhagic Septicemia in Calves

Abstract

Three groups of five calves, namely, V1, V2, and V3, were immunized intramuscularly at 4 and 8 weeks of age with ca. 10 9 , 10 8 , and 10 7 CFU, respectively, of a derivative of Pasteurella multocida B:2 wild-type strain 85020 containing a deletion in the aroA gene (strain JRMT12). The first and second vaccinations resulted in significantly (P < 0.01) higher rectal temperature responses in groups V1 and V2 than in group V3. Serum immunoglobulin M (IgM) and IgG titers did not increase in any group until after the second vaccination and were then significantly higher in groups V1 and V2 than in group V3 (P ‫؍‬ 0.001 for both IgM and IgG). All vaccinated groups and three unvaccinated challenge control calves (group CC) were injected subcutaneously at 10 weeks of age with ca. 10 7 CFU of strain 85020. Vaccinated calves survived the challenge, but two CC animals developed clinical disease and were killed for humane reasons. After challenge, mean serum amyloid A concentrations were significantly higher (P < 0.001) in the CC group than in the vaccinated groups. Postmortem examination revealed that calves in the CC group showed the most extensive range of bacteriologically positive tissues and gross and histopathological lesions. Overall, a clear dose-dependent response was present, with those receiving a higher vaccine dose being less affected clinically, bacteriologically, and pathologically by the wild-type challenge. The V2 treatment appeared to give the best combination of high immune response, protection, and safety.

Pasteurella

“…Systemic or intranasal vaccination of mice elicited solid immunity (Tabatabaei et al 2002 ). Unfortunately, in calves intramuscular injection of the vaccine was necessary to stimulate protective immunity, with intranasally vaccinated calves remaining completely susceptible (Hodgson et al 2005 ;Dagleish et al 2007 ).…”

Use of a Dual Reporter Plasmid to Demonstrate Bactofection with an Attenuated AroA- Derivative of Pasteurella multocida B:2

“…A live-attenuated vaccine for HS might be a better alternative vaccine as, by mimicking the ability of the pathogen to infect the host, but without causing disease, a more prolonged protective immune response may be induced. A live-attenuated vaccine developed by Tabatabaei et al [4], by mutating a housekeeping gene aroA , proved to be highly attenuated yet protective in mice and in cattle [4]–[6]. In later work, Othman et al [7] reported on the ability of the live vaccine strain to adhere to and to invade embryonic bovine lung (EBL) cells with an efficiency similar to the wild-type strain.…”

Systematic annotation and analysis of “virmugens”—Virulence factors whose mutants can be used as live attenuated vaccines

“…Specifically, 11 aroA , three aroC , and two aroD genes have been mutated and proven to be virmugens. Live attenuated vaccines have been generated by mutating aroA in 11 strains belonging to eight genus such as Bordetella [14], Pasteurella [15], Salmonella [16], Shigella [17], Staphylococcus [18], and Yersinia [19]. Except Gram-positive S. aureus , all other pathogens are Gram-negative.…”