Abstract: An indirect ELISA assay was constructed to detect porcine reproductive and respiratory syndrome virus （PRRSV） antibodies with recombinant GP5-encoding-epitopes protein.The optimal concentration of antigen was 7.5 μg/mL; The blocking buffer was 5% defatted milk powder with the blocking time 2 h，at 37 ℃；The serum sample was diluted in 1∶100 with incubated for 2 h at 37 ℃；The dilution of rabbit-anti-porcine IgG labeled by HRP was diluted in 1∶3000 with incubated for 2 h at 37 ℃；The TMB substrate was added and incubated at 37 ℃ for 15 min and then terminated with stopping solution. The standard of judgment was that the serum sample D_{450 nm} value with S/P≥0.254 was positive, and the sample D_{450 nm} value with S/P≤0.212 was negative. The recombinant antigen had no cross-reaction with antibodies of other five porcine diseases. 70 serum samples collected from pigs which were vaccinated with Ingelvac PRRS MLV were detected by this assay, the D_{450 nm} value of which were higher than 0.85. The results demonstrated that the establishment indirect ELISA method could be used for monitoring PRRSV antibody.

Key words: porcine reproductive and respiratory syndrome virus (PRRSV); recombinant GP5-encoding-epitopes protein; indirect ELISA