<p>Either VRS-purified culture supernatants from VEEV TC83 infected Vero cell or uninfected cells (negative control) were immobilised on 96well-microtiter plates. For the detection of a VEEV specific antibody titer, serial dilutions of pre-immune serum (PI 543) and immune serum (S543) after the sixth boost were applied. Bound antibodies were detected by rabbit anti-monkey IgG conjugated to horseradish peroxidase and staining with TMB.</p