Vaccine matching: reliability of foot-and-mouth disease (FMD) r-values determination

MATTION, NORA; GORIS, NESYA; WILLEMS, TOM; ROBIOLO, BLANCA; MARADEI, EDUARDO; SMITSAART, ELIANA; PEREZ BEASCOECHEA, CLAUDIA; PEREZ, ALEJANDRO,; FONDEVILLA, NORBERTO; PALMA, EDUARDO; DE CLERCQ, KRIS; LA TORRE, JOSE

Erice, Italia

Simposio; Session of the Research Group of the Standing Technical Committee of the European Commission for the Control of FMD; 2008

European Commission for the Control of FMD

Sera from animals involved in FMD vaccine potency and cross-protection trials performed using the Protection against Podal Generalization (PPG) test for two serotype A strains were analyzed by the virus neutralization test (VN) and liquid-phase ELISA (lpELISA) in three laboratories. Animals had been vaccinated with A24 Cruzeiro strain and challenged with homologous and heterologous (A/Arg/01) strains. Based on the PPG results, both FMDV strains were regarded as antigenically not closely related. Average VN r-values for medium and high serum titer classes from the A24 Cruzeiro vaccinated animals were in line with the heterologous PPG outcome for the three testing laboratories. The corresponding lpELISA r-values were slightly higher and indicated a closer relationship between both strains. Pooling of serum samples significantly reduced the inter-animal and inter-trial variation and led to r-values that mimicked the in vivo PPG cross-protection outcome.