Ahmed Ammad, Koma Mousa Komai
Department of Haematology and Immunology, Faculty of Medicine, Umm Al Qura University Makkah, Saudi Arabia.
Scand J Immunol. 2015 Aug;82(2):118-24. doi: 10.1111/sji.12312.
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.
B1 B淋巴细胞是主要存在于腹膜和黏膜部位的天然产生IgM的细胞。它们在早期抵抗病毒和细菌感染的过程中发挥着至关重要的作用。小鼠B1细胞在激活时表达IL-33受体复合物。IL-33是白细胞介素-1家族的新成员，在Th2免疫中发挥重要作用。人们已经认识到B1细胞通过响应白细胞介素-33产生IgM和IL-5来加剧接触性敏感。然而，IL-33/ST2信号在B1细胞中的具体反应尚未完全了解。在本研究中，我们报告小鼠B1细胞以ST2依赖的方式直接对IL-33作出反应。这种相互作用在体内以时间依赖的方式促使B1b细胞增殖。此外，它还通过B1细胞释放趋化因子（MCP-1和MIP-1α）介导单核细胞/巨噬细胞和粒细胞的募集。值得注意的是，在受到刺激后，B1b细胞还会额外释放血管生成诱导因子血管内皮生长因子和粒细胞-单核细胞集落刺激因子（GM-CSF）。我们的研究结果表明，这些IL-33介导的B1细胞可能在单核细胞和粒细胞的募集和生长中发挥重要作用。
