Journal of Vaccines & Vaccination

Construction and characterization of an acapsular mutant of Pasteurella multocida strain P-1059 (A:3)

3^rd International Conference on Vaccines & Vaccination

July 29-31, 2013 Embassy Suites Las Vegas, NV, USA

Entomack Borrathybay, Yu-Feng Zhang, Wulumuhan Nazierbieke and Feng-Juan Gong

Accepted Abstracts: J Vaccines Vaccin

Abstract:

T o further investigate the role of capsule involved in virulence of Pasteurella multocida P-1059 (A:3), a hexB deleted mutant was constructed by homologous recombination. The DNA replacement was confirmed by PCR, Reverse transcription (RT)-PCR and DNA sequencing. Experiments were conducted to compare the differences of biological characteristics such as capsular structure, capsular polysaccharide content, virulence and serum resistance between the hexB deleted mutant of ∆hexB and wild-type strain P-1059, as well as the complemented strain P-1059C. And the ability of the acapsular mutant ∆hexB to induced protection against wild-type challenge in chickens. Electron microscopy examination of the ∆hexB showed the absence of capsular material compared to the P-1059 and P-1059C. The ∆hexB was sensitive to the bactericidal action of chicken serum, whereas the P-1059 and P-1059C were both resistant. The ∆hexB was highly attenuated in chickens by intravenously injection, and intramuscular administration of ∆hexB to chickens stimulated significant protection against P-1059 and the homologous strain X-73(A:1). These results demonstrated that the capsule is a major virulence factor of Pasteurella multocida serotype A:3 strains.