Foot-and-Mouth Disease Virus (Type A) VP1 Structural Protein ELISA Antibody Detection Kit (Competitive Method)

Target and Hazard: Type A foot-and-mouth disease virus is the other major serotype of concern in China besides type O, and its field strains drift antigenically rather quickly, so cross-protection between circulating strains is incomplete. Infected cloven-hoofed animals show the typical vesicles, erosions and lameness, with feeding and milk production both affected, and calves and piglets may die suddenly of myocarditis. The disease is a Class I animal disease in China, and an outbreak requires quarantine, culling and suspension of livestock product movement, with severe consequences for farms and export trade.

Significance of Testing: Because of antigenic drift in type A strains, whether the vaccine strain still matches circulating strains is a central difficulty in control, making continued post-vaccination antibody monitoring particularly important. Coated with recombinant type A VP1 protein, this kit detects anti-VP1 antibodies in serum for monitoring neutralising antibody levels after type A vaccination, assessing immune qualification and verifying the effect of adjustments to the vaccination programme. Combined with testing for antibodies against type A non-structural protein, it further allows immune response and field infection to be distinguished.

Principle: Competitive ELISA: microplates are coated with recombinant type A VP1 protein; sample antibodies compete with an enzyme-labelled anti-VP1 monoclonal antibody for the antigenic sites, with colour becoming weaker as the antibody level rises, and results are interpreted by percent inhibition. Using a single structural protein as antigen reduces the cross-reactivity and non-specific reactions associated with whole-virus antigen.

Performance and Applications: 96-well format, approximately 40–44 samples per plate including controls; complete in about 2–2.5 hours; read at 450 nm and interpreted as percent inhibition (PI); store at 2–8 °C, protected from light, shelf life 12 months. Suitable for regular antibody monitoring of type A FMD-vaccinated pig, cattle and sheep herds and for epidemiological investigation by animal disease control institutions. Method: competitive ELISA (VP1 structural protein antigen) | Samples: serum (cattle/sheep/pig) | Assay time: ~2–2.5 h | Reading: microplate reader at 450 nm, interpreted as percent inhibition (PI) | Format: 96-well plate, ~40–44 samples per plate | Storage: 2–8 °C, protected from light; shelf life 12 months | Note: sensitivity, specificity, limit of detection, intra-/inter-assay CV and agreement with reference methods are subject to our internal QC report.