Figure 1

CD11b⁺ B1 cells express IL-10. (A) Adult peripheral blood mononuclear cells were immunofluorescently stained for surface CD3, CD20, CD27, CD43 and CD11b; and a representative sample with gating strategy used to identify naive (CD3⁻CD20⁺CD27⁻CD43⁻) and memory (CD3⁻CD20⁺CD27⁺CD43⁻) B cells and CD11b⁻ (CD3⁻CD20⁺CD27⁺CD43⁺CD11b⁻) and CD11b⁺ (CD3⁻CD20⁺CD27⁺CD43⁺CD11b⁺) B1 cells is shown. (B, C) Adult peripheral blood mononuclear cells were fixed, permeabilized and immunofluorescently stained for surface CD3, CD20, CD27, CD43 and CD11b, as well as intracellular IL-10. The fraction of naive (N) and memory (M) B cells and of CD11b⁻ (11b⁻) and CD11b⁺ (11b⁺) B1 cells is shown for a representative sample in (B) and for three independent samples in (C). Horizontal lines in (C) represent mean values and SEM. The cutoff for intracellular IL-10 positivity was determined on the basis of fluorescence-minus-one.