Fig. 8

FcγRIIB inhibits the proliferation of CD27⁻ naïve B cells but not CD27 ⁺ memory B cells. a CD27⁺ and CD27⁻ B cells (10⁶/ml) were cultured for two days before the addition of ³[H] methyl thymidine for another 16 h. Antibodies (5 μg/ml) and stimuli were added to cells in the beginning of culture as in Fig. 6. A representative histogram of more than 3 donors was shown. The asterisks indicate that the differences between the groups compared are statistically significant (P < 0.05). Similar results were obtained when cells were cultured for 1–2 more days before adding ³[H] methyl thymidine. b CD27⁺ and CD27⁻ B cells (10⁵/ml) from six donors were culture for 48 h in the presence of 2 μg/ml of F (ab’)₂ anti-Ig (IgM + IgG + IgA, Jackson Immunoresesearch) with (open circle) or without (closed circle) 10 μg/ml of ICs. Cells with decreased green fluorescence, indicative of cell division, were counted using flow cytometry and the absolute number (× 10²) was plotted as the Y-axis. The horizontal bar in each group represents mean of subjects and the asterisks indicate that the differences between the groups compared are statistically significant (P < 0.05)