Tuted with IL-10-/- B cells exhibited enhanced survival following

Tuted with IL-10-/- B cells exhibited enhanced survival following S. typhimurium infection, which was the result of amplified humoral immune responses not observed in mice reconstituted with wildtype B cells. In this model, B-cell immunoregulation was dependent on MyD88 and was specific to a suppression of neutrophils, NK cells, and T-cell cytokine responses. S. typhimurium infection also causes accumulation of CD138+ B cells in the spleen, and some of these cells may produce antibodies in response to infection. Notably, up to 50 of the CD138+ B cells in the spleens of B-green IL-10 reporter mice were reporter-positive 1 day following infection, indicating that some PNPP site regulatory B cells can inhibit immune responses against pathogens and express plasma cell-associated surface markers (56). However, the extent and specificities of antibodies produced by regulatory B cells during infection remain to be determined. B10 cells in cancer B10 cells are critical modulators of the anti-tumor immune response. A role for B-cell inhibition of tumor clearance was demonstrated in CD20-/- mice, where the presence of endogenous B cells decreased the therapeutic effect of CD20 mAb treatment (57). B-cell and B10 cell development, frequencies, and numbers are comparable between CD20-/- and C57BL/6 mice, but a single dose of CD20 mAb depletes more than 95 of blood, spleen, and lymph node B cells in wildtype mice, whereas endogenous B cells in CD20-/- mice remain intact. Similarly, CD20-/- mice given B cell lymphomas prior to CD20 mAb treatment had decreased survival and increased tumor volumes compared to tumor-bearing wildtype mice treated in the same fashion. While the presence of endogenous B cells negatively regulated anti-tumor responses in CD20-/- mice, a specific role for B10 cells in this phenomenon was demonstrated by the adoptive transfer of CD20-/- CD1dhi CD5+ B cells into tumor-bearing wildtype mice prior to CD20 mAb treatment. The transfer of this CD20-/- B10 cell-enriched population abrogated the therapeutic benefit of CD20 mAb, whereas the adoptive transfer of CD20-/- CD1dlo CD5- or CD20-/- IL-10-/- CD1dhi CD5+ B cells did not affect tumor growth or survival. Further experiments to understand the mechanism underlying B10 cell inhibition of CD20 mAb-dependent tumor clearance revealed a role for B10 cell regulation ofNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptImmunol Rev. Author manuscript; available in PMC 2015 May 01.Candando et al.Pagemacrophage activity. Macrophages cultured with CD1dhi CD5+ B cells produced less nitrous oxide and tumor necrosis factor-(TNF-) than did those cultured with CD1dlo CD5- B cells, an effect that was entirely dependent upon B cell IL-10 production (57). Thus, B10 cells specifically inhibit lymphoma depletion by CD20 mAb via the negative regulation of in vivo innate immune responses and potentially by additional mechanisms. As discussed later, patients with CLL commonly have enhanced serum IL-10 levels and some cases of CLL have elevated expression of T-cell leukemia protein 1 (TCL1), a transcription factor known to augment Akt purchase FCCP activation and subsequent cell proliferation and survival. These and other observations prompted B10 cell studies in TCL1 transgenic mice that overexpress human TCL1 and typically develop overt CLL-like disease by 12 months of age (58). While B10 cells develop normally and occur at comparable frequencies and numbers in 2-month-old TCL1 transgenic mice relative.Tuted with IL-10-/- B cells exhibited enhanced survival following S. typhimurium infection, which was the result of amplified humoral immune responses not observed in mice reconstituted with wildtype B cells. In this model, B-cell immunoregulation was dependent on MyD88 and was specific to a suppression of neutrophils, NK cells, and T-cell cytokine responses. S. typhimurium infection also causes accumulation of CD138+ B cells in the spleen, and some of these cells may produce antibodies in response to infection. Notably, up to 50 of the CD138+ B cells in the spleens of B-green IL-10 reporter mice were reporter-positive 1 day following infection, indicating that some regulatory B cells can inhibit immune responses against pathogens and express plasma cell-associated surface markers (56). However, the extent and specificities of antibodies produced by regulatory B cells during infection remain to be determined. B10 cells in cancer B10 cells are critical modulators of the anti-tumor immune response. A role for B-cell inhibition of tumor clearance was demonstrated in CD20-/- mice, where the presence of endogenous B cells decreased the therapeutic effect of CD20 mAb treatment (57). B-cell and B10 cell development, frequencies, and numbers are comparable between CD20-/- and C57BL/6 mice, but a single dose of CD20 mAb depletes more than 95 of blood, spleen, and lymph node B cells in wildtype mice, whereas endogenous B cells in CD20-/- mice remain intact. Similarly, CD20-/- mice given B cell lymphomas prior to CD20 mAb treatment had decreased survival and increased tumor volumes compared to tumor-bearing wildtype mice treated in the same fashion. While the presence of endogenous B cells negatively regulated anti-tumor responses in CD20-/- mice, a specific role for B10 cells in this phenomenon was demonstrated by the adoptive transfer of CD20-/- CD1dhi CD5+ B cells into tumor-bearing wildtype mice prior to CD20 mAb treatment. The transfer of this CD20-/- B10 cell-enriched population abrogated the therapeutic benefit of CD20 mAb, whereas the adoptive transfer of CD20-/- CD1dlo CD5- or CD20-/- IL-10-/- CD1dhi CD5+ B cells did not affect tumor growth or survival. Further experiments to understand the mechanism underlying B10 cell inhibition of CD20 mAb-dependent tumor clearance revealed a role for B10 cell regulation ofNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptImmunol Rev. Author manuscript; available in PMC 2015 May 01.Candando et al.Pagemacrophage activity. Macrophages cultured with CD1dhi CD5+ B cells produced less nitrous oxide and tumor necrosis factor-(TNF-) than did those cultured with CD1dlo CD5- B cells, an effect that was entirely dependent upon B cell IL-10 production (57). Thus, B10 cells specifically inhibit lymphoma depletion by CD20 mAb via the negative regulation of in vivo innate immune responses and potentially by additional mechanisms. As discussed later, patients with CLL commonly have enhanced serum IL-10 levels and some cases of CLL have elevated expression of T-cell leukemia protein 1 (TCL1), a transcription factor known to augment Akt activation and subsequent cell proliferation and survival. These and other observations prompted B10 cell studies in TCL1 transgenic mice that overexpress human TCL1 and typically develop overt CLL-like disease by 12 months of age (58). While B10 cells develop normally and occur at comparable frequencies and numbers in 2-month-old TCL1 transgenic mice relative.