Anti-tetC Ab contained in tetC^HIGH and tetC^INT PC subsets differed in their affinity for tetC. A flow cytometric assay was used to assess the specific tetC binding of the Ab synthesized by these PC subsets in which MFI of FITC-tetC staining is plotted against FITC-tetC concentration. A representative experiment of the saturation curves of tetC^HIGH PC (top panel) and tetC^INT PC (bottom panel) for FITC-tetC is shown. Insets show the corresponding Scatchard plots. B_max and relative K_D data are also included.