Fig. 5.

Determination of the limit of sensitivity of selected antibody pairs against PA and Etox. The lower limit of detection was determined for the indicated anti-PA IgG pairs from the Fab (A) and synthetic scFv (B) libraries, as well as anti-Etox pairs (C) from the Fab library in a sandwich ELISA using serially diluted PA or Etox antigen. Results shown are the average of three independent experiments with error bars showing standard error of mean. Signal-to-noise ratio is the ratio of the absorbance at the particular antigen concentration over the absorbance at 0 ng/ml concentration of antigen.