FIG. 1.

Principle of the competitive inhibition microsphere assay for the detection of pneumococcal capsular polysaccharide (PnPs) serotypes. The MFI of the test well is compared to that of the control well in which 89-SF binds to the pneumococcal capsular polysaccharide on the bead, resulting in a 100% signal. Capture antibody (89-SF) binds to any pneumococcal capsular polysaccharide present in samples whose serotypes are unknown and not to the pneumococcal capsular polysaccharide on the bead, resulting in a reduction in the MFI in the test well.