Abstract: The levels of the antibody response against PRRSV mutant strain(JXA1) inactivited vaccine were measured by ELISA at different time for pigs vaccinated with JXA1 inactivited vaccine(HP group, n=3), pigs inoculated with porcine circovirus type 2 (PCV2) and with JXA1 inactivited vaccine two weeks later (when PCV2 viremia was detected by PCR, PCV2/HP group, n=3), respectively.And distribution of genome or antibodies specific to PCV2 of HP group and PCV2/HP group were detected by ELISA or Real-time fluorescent PCR, respectively.The results showed that experimental infection of PCV2 was successful.In pigs inoculated with both PCV2 and JXA1 inactivited vaccine, the antibody response to JXA1 inactivited vaccine was significantly lower than that of animals treated with JXA1 inactivited vaccine vaccination alone at 70 days postvaccination(DPV).The average titers of antibodies against PRRSV in animals of HP group were obviously higher than those of the PCV2/HP group at 56,63 and 77 DPV, respectively.The positive rates of antibodies against PRRSV in pigs of HP group were 67% at 56 and 63 DPV, but those of PCV2/HP group were both 0. The positive rates of antibodies against PRRSV in pigs of HP group were 100% at 70 and 77 DPV, but those of PCV2/HP group were 0 and 33%, respectively.The results suggested that the infection of PCV2 could suppress the antibody response to JXA1 inactivited vaccine.

Key words: porcine circovirus type 2(PCV2); porcine reproductive and respiratory syndrome inactivated vaccine; humoral immune response