Figure 2

CD11b⁺ B1 cells spontaneously secrete IL-10. Adult peripheral blood mononuclear cells were immunofluorescently stained and sort-purified into populations of naive (CD20⁺CD27⁻CD43⁻) (N) and memory (CD20⁺CD27⁺CD43⁻) (M) B cells, total B1 (CD20⁺CD27⁺CD43⁺) cells and CD11b⁻ (CD20⁺CD27⁺CD43⁺CD11b⁻) (11b⁻) B1 cells that lack CD11b⁺ B1 cells. These populations were separately cultured for 5 d, after which supernatants were harvested and assayed for IL-10 by ELISA. Mean values (n = 3) are shown along with lines indicating SEM.