Single dilution avidity and IgG subtyping ELISAs applied as indirect assays to assess cross-protection against Foot and Mouth Disease Virus in cattle

CAPOZZO, ALEJANDRA VICTORIA

Tervuren

Workshop; DISCONVAC meeting October 2011; 2011

Comisión Europea (FP7)

The anti-foot and mouth disease virus (FMDV) serum antibody activity of protected and non protected animals immunized with an inactivated A 24 /Cruzeiro monovalent FMDV vaccine and challenged with the heterologous A/Argentina/2001 virus strain was evaluated. A single dilution avidity ELISA was set up to determine the avidity of specific antibodies. Isotype titration was also applied to titer FMDV-specific serum levels of IgG1 and IgG2. Avidity measurement could discriminate between protected and not protected animals, particularly when virus-neutralizing titers were low. Also, higher levels of IgG1 than IgG2 were found in vaccinated animals that were protected from challenge with either the homologous or heterologous strain. Animals protected against A/Arg/01 challenge with low or undetectable serum-neutralizing titers had high IgG1/IgG2 ratio. This study constitutes the proof-of-principle of the improvement of indirect testing applied to vaccine-matching trails by combining serum-virus neutralization together with avidity and subtyping of specific antibodies.