ORAL IMMUNIZATION OF MICE WITH ATTENUATED SALMONELLA-TYPHIMURIUM AROAEXPRESSING A RECOMBINANT MYCOPLASMA-HYOPNEUMONIAE ANTIGEN (NRDF)

Mycoplasma hyopneumoniae is the etiological agent of porcine enzootic pneumonia, a commercially expensive respiratory disease of swine, Salm onella typhimurium SL3261 was used as a live carrier of plasmid pKF1, which encodes a 15-kDa recombinant M. hyopneumoniae protein. This expr essed recombinant protein consists of the carboxy-terminal 11 kDa of a 42-kDa M. hyopneumoniae NrdF ribonucleotide reductase R2 subunit prot ein, Rabbit anti-15-kDa serum was able to inhibit the growth of viable M. hyopneumoniae J in vitro, When used as a live oral vaccine, S. typ himurium SL3261(pKF1) induced a significant secretory immunoglobulin A immune response in the lungs of mice orally immunized against the M. hyopneumoniae antigen. Utilization of live oral vaccines expressing po tentially protective M. hyopneumoniae proteins, such as the NrdF antig en, which can stimulate a lung mucosal response against surface-access ible proteins may provide a cost-effective alternative to the present control strategies used for porcine enzootic pneumonia.