We investigated cell-mediated immune responses to the P97 antigen of Mycoplasma hyopneumoniae in pigs vaccinated with the Erysipelothrix rhusiopathiae YS-19 strain expressing a recombinant protein of the P97 antigen on the cell surface. Nineteen pigs were divided into two groups; ten were intradermally immunized once with the YS-19 strain using a needle-free injector, and nine were intradermally inoculated with a medium. After immunization, peripheral blood mononuclear cells (PBMC) from the YS-19-immunized pigs did not significantly proliferate when stimulated with the P97 protein compared to those from the non-immunized pigs. However, after a challenge infection with a virulent M. hyopneumoniae strain, PBMC from the immunized pigs significantly proliferated. In these pigs, the severity of pneumonic lung lesions caused by the M. hyopneumoniae infection was significantly reduced (p<0.01). These results suggest that the P97-specific cell-mediated immune responses are important for resolving the M. hyopneumoniae infection.
(Research Team for Advanced Biologicals, +81-29-838-7790)
