Phenotype and purity of FDCs isolated from human tonsils. In (A), isolated HJ2⁺ cells were stained with Ki-M4 followed by PE-conjugated goat anti-mouse IgG specific antibodies. In (B), isolated cells were stained with PE-conjugated primary antibodies, and HJ2⁺ cells were examined for red fluorescence. The dotted line represents the fluorescent profile of HJ2⁺cells stained with a PE-conjugated isotype-matched control antibody. Ten thousand cells are displayed in each profile.