Abstract: Abstract VPg1-2, VPg2-3, VPg3 gene fragments were successfully subcloned from 3ABC gene of the foot-and-mouth disease virus ( FMDV ) Taibao strain and their expressing plasmids were constructed by inserting the target gene fragments into pGEX-4T-1 vector. The expressed proteins were analysed by Western blotting. The results showed that the expressed VPg1-2, VPg2-3 proteins reacted with FMDV positive serum while the reaction of the VPg3 protein was negative. An indirect ELISA was set up using purified VPg1-2 protein as antigen, and 4 groups of background-known cattle sera were tested. Negative results were obtained for the non-vaccinated control group and the vaccinated group and a part of the infected post-vaccination group(3/7). On the contrary, positive results were achieved for the infected group and a part of the infected post-vaccination group(4/7). In the infected group and infected post-vaccination group, the longest duration of the antibody against VPg1-2 lasted for at least 90 days. The earliest appearing time of VPg1-2 antibody was10 days after infection.

Key words: Foot-and-mouth disease virus, Non-structural protein, Antibody dynamics