The CD25+ B-cell subset secrete higher levels of IL-6, IL-10 and INF-γ, are more efficient antigen-presenting cells, and a higher frequency of this subset also produced higher levels of immunoglobulins of IgA, IgG and IgM isotypes spontaneously compared with CD25− B cells. In addition, CD25+ B cells secrete higher levels of antigen-specific antibodies of especially IgM, but also IgG class following OVA immunization in vivo. They have the ability to migrate towards the CXCL13, and

a higher number of cells expressed selected homing receptors in the CD25+ B-cell population than CD25− B cells. We suggest that CD25 is a developmental marker of B cells, and the CD25+ B-cell population is functionally different from the CD25− population and might belong to the memory B-cell population. Knowledge see more about murine CD25+ B cells from

secondary lymphoid organs is scarce. It has been shown that B cells during their development in the bone marrow, at the pre-B-cell stage, express high levels of CD25 [8, 9]. The expression of CD25 is, however, down regulated, while the B cells mature and leave the bone marrow. Currently, CD25 together with CD69 is used as a marker for activated B cells in vitro, but there are to our knowledge no studies aiming to examine the functional properties of these cells in vivo. Although it is common knowledge that the major function Saracatinib of B cells is to produce antibodies, B cells also have the capacity to produce different spectrum of cytokines [14]. Harris et al. has shown that cytokine-producing B cells can be divided in to two effector subsets – Be1 (producing mainly IFN-γ, IL-12, LTα) and Be2 (producing IL-4, IL-6, IL-2). These cytokines Dipeptidyl peptidase have the ability to regulate the differentiation and expansion of naïve T cells in to the Th1 and Th2 subsets [15]. In addition, a third B-cell effector subset regulatory B cells (Breg) mainly produce IL-10 and has been shown to play a key role in controlling autoimmunity [16–19], allergy [20, 21] and chronic intestinal inflammation [22]. To reveal the cytokine production pattern, CD25+ B cells were stimulated

with the TLR2-, TLR4- and TLR9- agonists resulting in a high production of IL-6, IFN-γ, IL-10 and to some extend IL-4. Cytokines like IL-6 and IFN-γ may also function directly on B cells inducing differentiation of B cells into antibody producing cells [23–26], while the effects of IL-10 on murine B cells is still under discussion [27, 28]. No IL-2 could be detected and that may be a result of autocrine consumption, as CD25 expressing B cells express the high affinity IL-2 receptor and the CD25 negative B cells have the intermediate IL-2 receptor. We could detect a broad array cytokines produced by CD25+ B cells in response to different stimulatory agents. These findings suggest that the CD25+ subpopulation of B cells are an important source of cytokines and might have impact on the outcome of the immune response.