To wildtype mice, there is an observed ageassociated expansion of blood

To wildtype mice, there is an observed ageassociated expansion of blood and spleen B10 cells by 6 months of age. Indeed, by 12 months, most TCL1 transgenic mice have 50?0 B10 cell frequencies among spleen B cells, versus 10 for age-matched wildtype mice, leading to an average fourfold expansion of total B10 cell numbers. The age-associated expansion of B10 cells in TCL1 transgenic mice is strongly correlated with the increased acquisition of a CLL-like cell surface phenotype (CD5+ B220int) among all B cells. The massive expansion of IL-10competent B cells always preceded the development of malignant CLL-like cells in TCL1 transgenic mice. As is the case for endogenous B10 cells, activated but not resting CLL-like cells inhibited macrophage TNF- production, an effect that was entirely dependent on IL-10 secretion. Additionally, low-dose inflammation induced by injections of small quantities of LPS resulted in CLL-like cell production of IL-10 and increased levels of serum IL-10 in TCL1 transgenic mice. These results suggest that infectious or other inflammatory responses may enhance CLL cell IL-10 competence and secretion, which may contribute to the systemic immunosuppression that is observed in patients with CLL and significantly influence disease treatment and progression. Thus, the shared ability of B10 and CLL cells from TCL1 transgenic mice to secrete IL-10, inhibit innate effector cell activation, and express CD5 indicate that either similar molecular processes, comparably self-reactive BCRs, or shared cellular origins dictate the IL-10-dependent regulatory function observed in both B10 and CLL cells.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptHuman B10 cellsHuman B10 cell identification IL-10-competent B10 cells have been recently characterized in humans (59). Human B10 cells are order ML390 easily visualized following a 5-h ex vivo stimulation with PMA and ionomycin plus brefeldin-A (together, PIB) to block protein secretion. B10 cells are present in low but detectable numbers in human blood (0.8 ?0.1 of total B cells, 1.9 ?0.3 ?10-3 B10 cells/ml blood) and have also been identified in the spleen (0.31 ?0.06 ), tonsils (0.31 ?0.11 ), and newborn cord blood (0.45 ?0.14 ). Blood B10 cell numbers appear to decrease with advanced age (59). As in mice, the addition of different TLR agonists to these cultures does not significantly affect the overall mean frequencies of blood B10 cells fromImmunol Rev. Author manuscript; available in PMC 2015 May 01.Candando et al.buy BRDU Pagehealthy individuals. Thereby, B10 cells are present at low but readily identifiable numbers in humans as in mice.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptMouse B10pro cell maturation into B10 cells occurs during in vitro culture with agonistic CD40 mAb as discussed earlier. Human B10pro cells are visualized in a similar manner, where the culture of blood B cells with recombinant CD154 and CpG for 48 h induces the maturation of B10pro cells into B10 cells that then express IL-10 in response to PIB stimulation for 5 h (59). These cultures thereby enumerate the numbers of in vitro matured B10pro cells as well as ex vivo B10 cells, because both subsets express IL-10 after PIB stimulation (7.0 ?1.4 of total B cells, 1.6 ?0.3 ?10-4 B10 + B10pro cells/ml blood). Signaling pathways similar to those observed for mice induce human B10pro cell maturation and IL-10 expression, although select individuals have increased B10 cell.To wildtype mice, there is an observed ageassociated expansion of blood and spleen B10 cells by 6 months of age. Indeed, by 12 months, most TCL1 transgenic mice have 50?0 B10 cell frequencies among spleen B cells, versus 10 for age-matched wildtype mice, leading to an average fourfold expansion of total B10 cell numbers. The age-associated expansion of B10 cells in TCL1 transgenic mice is strongly correlated with the increased acquisition of a CLL-like cell surface phenotype (CD5+ B220int) among all B cells. The massive expansion of IL-10competent B cells always preceded the development of malignant CLL-like cells in TCL1 transgenic mice. As is the case for endogenous B10 cells, activated but not resting CLL-like cells inhibited macrophage TNF- production, an effect that was entirely dependent on IL-10 secretion. Additionally, low-dose inflammation induced by injections of small quantities of LPS resulted in CLL-like cell production of IL-10 and increased levels of serum IL-10 in TCL1 transgenic mice. These results suggest that infectious or other inflammatory responses may enhance CLL cell IL-10 competence and secretion, which may contribute to the systemic immunosuppression that is observed in patients with CLL and significantly influence disease treatment and progression. Thus, the shared ability of B10 and CLL cells from TCL1 transgenic mice to secrete IL-10, inhibit innate effector cell activation, and express CD5 indicate that either similar molecular processes, comparably self-reactive BCRs, or shared cellular origins dictate the IL-10-dependent regulatory function observed in both B10 and CLL cells.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptHuman B10 cellsHuman B10 cell identification IL-10-competent B10 cells have been recently characterized in humans (59). Human B10 cells are easily visualized following a 5-h ex vivo stimulation with PMA and ionomycin plus brefeldin-A (together, PIB) to block protein secretion. B10 cells are present in low but detectable numbers in human blood (0.8 ?0.1 of total B cells, 1.9 ?0.3 ?10-3 B10 cells/ml blood) and have also been identified in the spleen (0.31 ?0.06 ), tonsils (0.31 ?0.11 ), and newborn cord blood (0.45 ?0.14 ). Blood B10 cell numbers appear to decrease with advanced age (59). As in mice, the addition of different TLR agonists to these cultures does not significantly affect the overall mean frequencies of blood B10 cells fromImmunol Rev. Author manuscript; available in PMC 2015 May 01.Candando et al.Pagehealthy individuals. Thereby, B10 cells are present at low but readily identifiable numbers in humans as in mice.NIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptMouse B10pro cell maturation into B10 cells occurs during in vitro culture with agonistic CD40 mAb as discussed earlier. Human B10pro cells are visualized in a similar manner, where the culture of blood B cells with recombinant CD154 and CpG for 48 h induces the maturation of B10pro cells into B10 cells that then express IL-10 in response to PIB stimulation for 5 h (59). These cultures thereby enumerate the numbers of in vitro matured B10pro cells as well as ex vivo B10 cells, because both subsets express IL-10 after PIB stimulation (7.0 ?1.4 of total B cells, 1.6 ?0.3 ?10-4 B10 + B10pro cells/ml blood). Signaling pathways similar to those observed for mice induce human B10pro cell maturation and IL-10 expression, although select individuals have increased B10 cell.