The pathogenicity of two recent German field isolates of Porcine parvovirus (PPV-27a and PPV-143a) and two vaccine viruses [PPV-NADL-2 and PPV-IDT (MSV)], which are used for the production of inactivated vaccines, was investigated by inoculation of pregnant sows at day 40 of gestation. Post-infection sera of these sows as well as antisera prepared in rabbits by immunization with the four above-mentioned PPV isolates and with the virulent strain PPV-Challenge (Engl.) were tested for their homologous and heterologous neutralization activities. All antisera had high neutralization activity against the vaccine viruses, the PPV-Challenge (Engl.) virus and PPV-143a, but much lower activity against PPV-27a. These results suggest that PPV-27a represents a new antigenic variant or type of PPV and vaccines based on the established vaccine viruses may not be fully protective against this field isolate. PPV-27a has been characterized based on the amino acid sequences of the capsid protein as a member of a new and distinct PPV cluster (Zimmermann et al., 2006). Interestingly, the homologous neutralizing antibody titres of the sera of all three pigs and both rabbits inoculated or immunized with PPV-27a were 100-to 1000-fold lower than the heterologous titres against any of the other viruses. The low homologous neutralizing antibody titres suggest a possible, yet undefined, immune escape mechanism of this PPV isolate.

No abstract

The pathogenicity of two recent German field ISolates of Porcine parvovirus (PPV-27a and PPV 143a) and two vaccine viruses [PPV-NADL-2 and PPV-IDT (MSV)], which are used for the production of inactivated vaccines, was mvestigated by maculation of pregnant sows at day 40 of gestation. Post-infect1on sera of these sows as well as antisera prepared in rabbits by 1mmun1zation with the four above-mentioned PPV isolates and with the virulent strain PPV-Challenge (Engl.) were tested for their homologous and heterologous neutralization activities All ant1sera had h1gh neutralization activities against the vaccme wuses , the PPV-Challenge (Engl) and PPV-143a , but much lower activity against PPV-27a These results suggest that PPV-27a represents a new antigenic variant or type of PPV and vacc1nes based on the established vaccine viruses may not be fully protective against th1s field ISolate. PPV-27a has been charactenzed based on the ammo ac1d sequences of the capsid protem as a member of a new and distmct PPV cluster. lnterestmgly, the homologous neutralizing antibody titres of the sera of all three p1gs and both rabbits maculated or Immunized with PPV-27a were 100-to 1 000-fold lower than the heterologous titres aga1nst any of the other viruses. The low homologous neutrahz1ng ant1body t1tres suggest a possible, yet undefined , immune escape mechanism of this PPV isolate.