Submitted to: American Society for Microbiology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2007
Publication Date: May 19, 2007
Citation: Register, K.B., Sacco, R.E., Brockmeier, S. 2007. Immune Response in Mice and Swine to a DNA Vaccine Derived from the Pasteurella multocida toxin gene[abstract]. American Society for Microbiology Meeting. May 21-25, 2007, Toronto, Canada. 2007 CD-ROM.
The Pasteurella multocida toxin (PMT) is a primary virulence factor in swine atrophic rhinitis and PMT-specific antibody plays a major role in protection against the disease. However, currently available vaccines contain low levels of PMT and do not induce optimal antibody responses. Two vaccines were constructed from the P. multocida toxin gene, genetically detoxified by the introduction of a point mutation, and DNA vaccine vectors distinguished by the presence or absence of a secretion signal sequence. Following immunization of mice or pigs, PMT-specific antibody responses were measured by ELISA and expression of interferon-gamma was evaluated as a marker for cellular immune responses. In mice, PMT-specific spleen cell secretion of interferon-gamma was measured by ELISA; in pigs, expression of interferon-gamma from peripheral mononuclear cells was evaluated by realtime RT-PCR. Optimal antibody and interferon-gamma responses in mice were achieved with pMM4, the construct containing a signal sequence. Antibody and interferon-gamma responses were also induced in pigs immunized with pMM4 and levels of both increased significantly following booster injections and experimental infection with P. multocida. This study demonstrates, for the first time, the ability of a DNA vaccine to elicit humoral and cell-mediated immune responses to the P. multocida toxin in both mice and swine.