title: Interleukin-33 Triggers B1 Cell Expansion and Its Release of Monocyte/Macrophage Chemoattractants and Growth Factors.
abstract: B1 B lymphocytes are natural IgM-producing cells primarily found in peritoneum and mucosal sites. They perform vital functions during the early defence against viral and bacterial infections. Murine B1 cells express IL-33 receptor complex on activation. IL-33 is a new addition to the IL-1 family with a strong role in Th2 immunity. B1 cells have been recognized to exacerbate contact sensitivity by producing IgM and IL-5 in response to interleukin-33. However, the exact response of IL-33/ST2 signalling in B1 cells is not completely understood. In this study, we report that murine B1 cells respond directly to IL-33 in a ST2-dependent manner. This interaction instigates B1b cell proliferation in a time-dependent manner in vivo. Furthermore, it also mediates monocyte/macrophage and granulocyte recruitment via B1 cell release of chemokines (MCP-1 and MIP-1 alpha). It was noted that upon stimulation, B1b cells additionally release an angiogenic inducer vascular endothelial growth factor and granulocyte-monocyte colony-stimulating factor (GM-CSF). Our findings suggest that these IL-33-mediated B1 cells might be able to play a vital role in the recruitment and growth of monocytes and granulocytes.
authors.affiliation: Department of Haematology and Immunology, Faculty of Medicine, Umm Al Qura University Makkah, Saudi Arabia.
authors.forename: Ammad
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: Department of Haematology and Immunology, Faculty of Medicine, Umm Al Qura University Makkah, Saudi Arabia.
authors.forename: Mousa Komai
authors.initials: MK
authors.lastname: Koma
mesh_terms: D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D054405:Chemokine CCL3 / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis; D006098:Granulocytes / Q000276:immunology*; D000072179:Interleukin-1 Receptor-Like 1 Protein; D000067596:Interleukin-33; D007378:Interleukins / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D018123:Receptors, Interleukin / Q000235:genetics*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D054405:Chemokine CCL3; C486189:Il1rl1 protein, mouse; C506535:Il33 protein, mouse; D000072179:Interleukin-1 Receptor-Like 1 Protein; D000067596:Interleukin-33; D007378:Interleukins; D018123:Receptors, Interleukin; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D016178:Granulocyte-Macrophage Colony-Stimulating Factor