FIG. 4.

Macrophage transfer reaction of pneumococci from WT mouse, CR1⁺ mouse, or human erythrocytes. The transfer reaction was conducted by incubating J774A.1 cells with pneumococci adherent to erythrocytes for 30 min prior to fixation and subsequent analysis by flow cytometry. The amount of bacteria transferred to macrophages was measured as the mean fluorescence (MF) acquired by the macrophages. The asterisk indicates that significantly more pneumococci were transferred from erythrocytes (E) of CR1⁺ mouse and human than from WT mouse (P < 0.01 by a Student's two-tailed t test). Error bars indicate the SD of data from triplicate samples.