Hao-Yong Zou, Xiao Fei Wang, Feng-Ying Ma, Pin Chen, Wen-Tao Li, Xin-Jun Liu, Yang Wang and Qi-Gai He
The immunogenicity of the P97 adhesin repeat region R1 (P97R1) and the ribonucleotide reductase R2 subunit (NrdF) antigens of Mycoplasma hyopneumoniae were evaluated as vaccines in mice. Mice were immunized orally or injected intramuscularly (IM) with attenuated Salmonella enterica serovar Choleraesuis strain C501 harboring a prokaryotic expression vector encoding P97R1 and NrdF (pYA97R1N). Local and systemic immune responses were analyzed in vaccinated mice. The results showed that P97R1N-specific serum IgG and IgA antibodies were detected in serum and lung samples. P97R1-specific serum IgG and IgA antibodies were also detected in serum, but in lung sample only P97R1-specific IgG response was induced. ELISA assays demonstrated that IFN-Û and IL-4 production was induced in cultural supernatants from splenocytes stimulated with specific antigens in vitro. M. hyopneumoniae whole cell-specific antibody was induced in vaccinated mice and a good immunogenic effect by this vaccine was indicated. Importantly, animals vaccinated by IM had higher levels of P97R1N-specific IgG and IgA than those vaccinated by oral route. Furthermore, mice immunized with the C501 vaccine elicited significantly higher levels of P97R1N-specific IgA and IgG in lungs and serum (P<0.05), and IFN-Û and IL-4, than those who received the live M.hyopneumoniae vaccine. Taken together, these results suggest that IM vaccination with the
C501 vaccine might provide an effective method of inducing an immune response to M. hyopneumoniae.