1. To study the differences in cytokine production between CD25+ and CD25− B cells, we used the TLR selleck chemicals ligands, Pam3Cys, LPS and CpG stimulating TLR 2, 4 and 9, respectively. The results are summarized in Table 1. The levels of IL-6 in supernatants from CD25+ B cells were significantly higher when compared with

CD25− B cells following stimulation for 12 h with CpG-PS, LPS or Pam3Cys (P < 0.05, respectively). In addition, CD25+ B cells secreted significantly higher levels of INF-γ as well as IL-10 following 72 h stimulation with CpG-PS, LPS and Pam3Cys (P < 0.05, respectively). Finally, CD25+ B cells produced significantly higher levels of IL-4 following 72 h of stimulation with CpG-PS (P < 0.05) when compared with CD25− B cells. The levels of IL-2 and TNF were analysed at the different time points (24 and 72 h); however, no secretion was detected (data not shown). The increased cytokine production after TLR stimulation was not because of a higher proliferation rate within the CD25+ B-cell subset compared with CD25− B cell as we did not detect any difference in the proliferative ability of these cell populations (data not shown). To BI 6727 manufacturer investigate if there was any difference in the ability of CD25+ B cells to present antigens to CD4+ T cells, we used a mixed lymphocyte reaction (MLR) as

an alloantigenic stimulation. CD25+ B cells are significantly better at presenting alloantigen

to CD4+ T cells when compared with CD25− B cells (P < 0.05) (Fig. 2). To evaluate if there were any differences in spontaneous immunoglobulin secretion between naïve CD25+ and CD25− B cells, we performed ELISPOT assays detecting IgA, IgG and IgM secreting B cells and found that the frequency of CD25+ B cells secreting immunoglobulins of IgA, IgG and IgM class was significantly increased compared with CD25− B cells (P < 0.05, respectively) (Fig. 3A). To analyse the Galactosylceramidase ability of CD25+ B cells to produce antigen-specific antibody, mice were immunized with OVA. At day 14 after immunization, we found that the frequency of CD25+ B cells secreting OVA-specific IgM antibodies were significantly (P < 0.01) increased compared with CD25− B cells (Fig. 3B), whereas the difference regarding the IgG response was less pronounced (P < 0.05). The levels of IgA secretion were very low in both groups, and there was no significant difference in the number of IgA OVA-specific secreting cells between the populations. We found that CD25+ B cells migrated significantly better both spontaneously and towards the recombinant mouse chemokine CXCL13 (P < 0.05, respectively) than CD25− B cells (Fig. 4). The number of CD25+ B cells expressing homing receptors was significantly increased compared with CD25− B cells with respect to α4β7, CD62L, CXCR4 and CXCR5 (P < 0.01, and P < 0.05, respectively) (Fig. 5A–D).