Development and validation of a prokaryotically expressed foot-and-mouth disease virus non-structural protein 2C'3AB-based immunochromatographic strip to differentiate between infected and vaccinated animals

In this study, an immunochromatographic strip with non-structural protein (NSP) 2C'3AB was developed and validated to differentiate foot-and-mouth disease infected from vaccinated animals. A part of N-terminal of 2C protein gene and whole 3AB gene were connected and prokaryotically expressed as the antigens labeled with colloidal gold was used as the detector, the 2C'3AB protein and rabbits anti-2C'3AB antibodies were blotted on the nitrocellulose(NC) membrane for the test and control lines, respectively. 387 serum samples were collected to evaluate the characteristics of the strip in comparison with existing commercial 3ABC antibody ELISA kit. The coincidence rate of pigs negative serum, pigs vaccinated serum, pigs infected serum was 100%, 97.2%, 95.0%, respectively. The coincidence rate of cattle negative serum, cattle vaccinated serum, cattle infected serum was 100%, 96.7%, 98.0%, respectively. The coincidence rate of sheep negative serum, sheep infected serum was 97.6%, 96.3%, respectively. The strip was shown to be of high specificity and sensitivity, good repeatability and stability.These data suggest that the immunochromatographic strip is a useful tool for rapid on-site diagnosing animals infected foot-and-mouth disease virus.Foot-and-mouth disease (FMD) is an extremely contagious viral disease of cattle, pigs, sheep, goats, and many cloven-hoofed wild animals. The disease is widespread and causes significant economic losses. The causal agent, FMD virus (FMDV), is a positive-sense single-stranded RNA virus that is a member of the genus Aphthovirus in the family Picornaviridae and occurs as seven distinct serotypes throughout the world: A, O, C, Asia1 and South African Territories (SAT) 1-3. The non-structural proteins (NSPs) are conserved amongst the seven serotypes[1,2]. FMDV serotypes O, Asia 1 and A have circulated separately in China during the last fifty years[3-6], and eliminating infected animals and vaccination are the main policies to prevent and co