EVALUATION OF THE ABILITY OF EUROPEAN-TYPE PRRS MLV VACCINES TO INDUCE CROSS-NEUTRALIZATION WITH DIFFERENT FIELD STRAINS

摘要

Porcine reproductive and respiratory syndrome virus is very heterogeneous and this heterogenicity might affect the efficacy of the vaccines in controlling the disease (3). In fact, limited crossprotection has been experimentally demonstrated when vaccinated pigs are exposed to a heterologous challenge (1). Although the components of the immune response implicated in the induction of protective immunity have not been completely elucidated, there is some experimental data that indicates that neutralizing antibodies might play a significant role in protection (4). The objective of the present study was to evaluate and compare the ability of three European-type modified-live-virus (MLV) vaccines to induce neutralizing antibodies effective in the neutralization of different field PRRSV strains.