Detection of Antibodies against Non-Structural Proteins of Foot-and-Mouth Disease Virus using ELISA: a field application
Tsu-Han Chen
Abstract
Foot-and-mouth disease (FMD) is a highly contagious blistering disease in pigs that causes serious economic losses on pig farms. In this project we use a prokaryotic expression system to establish a double antibody sandwich ELISA diagnostic method for the detection of antigens of non-structural proteins (NSP) of the foot-and-mouth disease virus (FMDV). The first tasks were to design specific primers that bind to NSP immunological epitopes on the FMDV genome, and to amplify the target genes using RT-PCR. The 3ABC, 3A, 3B, 2C and 3D genes were then cloned and expressed through the prokaryotic expression system. The results showed that the sequencing of the five FMDV-NSP nucleic acid sequences were in frame, and the molecular weight of the expressed recombinant proteins were determined as predicted. The sensitivity of the FMDV-NSP antibody assay using the sandwich ELISA method confirmed that the limiting dilution was 1:100, and that it could specifically bind to the FMDV antisera in cows, pigs and goats. The results obtained from the sandwich ELISA were consistent with those from a commercial ELISA kit in detecting sera from 174 pigs in the field. Neither antisera against swine vesicular disease (SVDV) nor sera against Seneca valley virus (SVV) could be detected by this sandwich ELISA method.