FIG. 1.

Time course of CRP binding to piliated N. meningitidis C311. Piliated C311 cells were grown in MHB, dried on microtiter plates, and probed with CRP-AP in the presence of calcium (squares) or EDTA (triangles). Plates were washed thoroughly, and the remaining CRP-AP was detected by adding pNPP substrate and measuring the optical density at 405 nm with a reference wavelength of 490 nm. The dashed line is the growth curve of the cultures measured by optical density. Data are the means from four replicate experiments ± standard deviations.