FIG. 1.

Optimization of ELISA plate coating conditions by checkerboard titration of PS and mHSA concentrations for pneumococcal types 19F and 23F. Concentrations of 0, 1.0, 2.5, and 5.0 μg of mHSA per ml comixed with each of four different PS concentrations were used. Serum 89SF was used at a dilution of 1:400. Absorbance values were read 20 to 40 min after addition of the substrate and were normalized to the values that would have occurred at 100 min.