Figure 1. Determination of antibody titers in ponies vaccinated with Septavacc.

Serum samples (A) and nasal washes (B) were taken from vaccinated ponies before immunization (white bars) or 12 days after third immunization (dark grey bars). Serum samples were also taken 11 days after second vaccination (light grey bars in panel a). Microtiter plates were coated with indicated antigens and ELISA was performed as described earlier [7]. The dilutions required to obtain an absorbance of 1.0 for nasal wash samples and 1.5 for sera were calculated; the titration curves are linear and parallel at these values. The average and standard error of the mean (SEM) of log values of these dilutions are plotted. All increases of IgG titers are significant. IgA was determined using nasal washes diluted 2-fold and the absorbance value plotted; white bars before immunization and grey bars after third vaccination (C).