Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Division of Basic Science, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
J Immunol. 2010 Jun 15;184(12):6688-94. doi: 10.4049/jimmunol.0903984. Epub 2010 May 17.
Beta-defensins play a dual role during immune response. Their direct antimicrobial properties contribute to the local innate immune response by combating microbial invasions. Furthermore, previous studies revealed the capacity of certain beta-defensin family members to chemoattract immature dendritic cells and CD45RO+ CD4+ T cells through chemokine receptor CCR6. However, because beta-defensins also chemoattract macrophages and monocytes, which do not express CCR6, efforts have been made to identify other receptors for these polypeptides. In this study, we demonstrate the capacity of human beta-defensin (hBD)2 and 3 and their mouse orthologs, beta-defensin 4 and 14, to interact with CCR2, a chemokine receptor expressed on monocytes, macrophages, and neutrophils. These beta-defensins, fused to the Fc region of human IgG1, showed binding to CCR2-transfected HEK293 cells, as revealed by flow cytometry. The beta-defensin fusion proteins also induced CCR2-specific chemotaxis of transfected HEK293 cells, human peripheral blood monocytes, and mouse peritoneal exudate cells in a dose-dependent manner. Preincubation of human monocytes with CCL2/MCP-1, the chemokine ligand for CCR2, abolished migration induced by beta-defensins. Conversely, preincubation with hBD2:Ig or hBD3:Ig inhibited MCP-1 induced migration. Peritoneal exudate cells from CCR2-deficient mice failed to migrate toward these fusion proteins. In conclusion, the beta-defensins used in this study contribute to the innate and adaptive immune response in their role as chemoattractants. Our data indicate that hBD2 and hBD3, together with their mouse orthologs (beta-defensin 4 and 14), are chemotactic for a broad spectrum of leukocytes in a CCR6- and CCR2-dependent manner.
β-防御素在免疫反应中发挥双重作用。它们的直接抗菌特性通过对抗微生物入侵来促进局部先天免疫反应。此外，先前的研究表明，某些β-防御素家族成员能够通过趋化因子受体 CCR6 趋化未成熟树突状细胞和 CD45RO+ CD4+T 细胞。然而，由于β-防御素也趋化表达 CCR6 的巨噬细胞和单核细胞，因此人们一直在努力寻找这些多肽的其他受体。在这项研究中，我们证明了人β-防御素（hBD）2 和 3 及其鼠同源物β-防御素 4 和 14 与表达于单核细胞、巨噬细胞和中性粒细胞上的趋化因子受体 CCR2 相互作用的能力。这些与人 IgG1 Fc 区融合的β-防御素通过流式细胞术显示与转染的 HEK293 细胞结合。β-防御素融合蛋白还以剂量依赖性方式诱导转染的 HEK293 细胞、人外周血单核细胞和鼠腹腔渗出细胞的 CCR2 特异性趋化。用趋化因子配体 CCL2/MCP-1（CCR2 的趋化因子配体）预先孵育人单核细胞可消除β-防御素诱导的迁移。相反，用 hBD2:Ig 或 hBD3:Ig 预处理可抑制 MCP-1 诱导的迁移。来自 CCR2 缺陷型小鼠的腹腔渗出细胞不能向这些融合蛋白迁移。总之，本研究中使用的β-防御素作为趋化因子在其作为趋化因子的作用中有助于先天和适应性免疫反应。我们的数据表明，hBD2 和 hBD3 与其鼠同源物（β-防御素 4 和 14）一起，以 CCR6 和 CCR2 依赖的方式对广泛的白细胞具有趋化性。
