Human Eos promote human B cell proliferation and immunoglobulin secretion. A, CpG-stimulated B cells were cultured in the absence or presence of increasing numbers of Eos and proliferation was assessed by [3H]TdR-incorporation. B-D, B cells isolated from PB (B), tonsils (C), and spleens (D) were assessed for proliferation in culture with or without CpG stimulation and in the absence or presence of Eos. E-F, PB B cells were separated into naïve (E) and memory (F) cells and proliferation was assessed ± CpG stimulation in the absence or presence of Eos. G, CpG-stimulated B cells were cultured with or without Eos for 10 days and immunoglobulin levels were measured in the cell-free supernatants by ELISA. n.d., not detected. * p<0.05; ** p<0.01; *** p<0.001; n.s., not significant.