Antibody responses induced in mice immunized with recombinant adenovectors expressing chimeric proteins of various porcine pathogens

• Chimeric proteins from various important porcine pathogens were expresssed from adenovectors.
• These chimeric proteins induced specific antibody responses in mice inoculated with the adenovectors.
• The protein P97c of Mycoplasma hyopneumoniae exerted an immunopotentiator effect.

Porcine reproductive and respiratory syndrome virus (PRRSV), Porcine Circovirus type 2 (PCV2) and Mycoplasma (M.) hyopneumoniae are swine pathogens of economic importance. Although vaccines are available for each pathogen, no commercial bivalent vaccines have been developed so far. In this study, recombinant adenovectors (AdVs) expressing proteins of each pathogen were developed and their immunogenicity tested in mice. The proteins of interest were the glycoprotein GP5 of PRRSV, the capsid (Cap) protein of PCV2b and the C-terminal portion of P97 (P97c) protein of M. hyopneumoniae that were used alone and/or in fusion which each other. Inoculation of mice with the AdVs resulted in antibody (Ab) responses specific to the immunogens. Unexpectedly, immunization with vaccines expressing P97c in fusion to either Cap or GP5 enhanced the Ab responses against Cap and GP5, suggesting an immunopotentiator effect for P97c.