Satake Y, Akiba H, Takeda K, Atsuta M, Yagita H, Okumura K
Department of Immunology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
Biochem Biophys Res Commun. 2000 Apr 21;270(3):1041-8. doi: 10.1006/bbrc.2000.2560.
OX40 (CD134) is a member of the tumor necrosis factor (TNF) receptor superfamily first identified as a rat T cell activation marker. We previously identified the rat ligand for OX40 (OX40L) by molecular cloning. In the present study, we newly generated an anti-rat OX40L mAb (ATM-2) that can inhibit the binding of OX40 to rat OX40L and thus efficiently inhibits the T cell costimulatory activity of rat OX40L. Flow cytometric analyses using ATM-2 and an anti-rat OX40 mAb (MRC OX40) indicated that OX40 was inducible on splenic CD4(+) T cells by stimulation with immobilized anti-CD3 mAb, while OX40L was not expressed on resting or activated T cells. OX40L was expressed on splenic B cells after stimulation with lipopolysaccharide (LPS), but not on peritoneal macrophages. Interestingly, splenic dendritic cells (DC) expressed OX40L constitutively, which was further upregulated by LPS stimulation. The potent costimulatory activities of splenic DC for anti-CD3-stimulated rat CD4(+) T cell proliferation and cytokine (IL-2, IFN-gamma, IL-10, and IL-13) production were substantially inhibited by ATM-2. These results indicated that OX40L is expressed on professional antigen-presenting cells (APC), and may be involved in humoral immune responses via T-B interaction and in cellular immune responses via T-DC interaction in the rat system.
OX40（CD134）是肿瘤坏死因子（TNF）受体超家族的成员，最初被鉴定为大鼠T细胞活化标志物。我们之前通过分子克隆鉴定出了OX40的大鼠配体（OX40L）。在本研究中，我们新制备了一种抗大鼠OX40L单克隆抗体（ATM-2），它可以抑制OX40与大鼠OX40L的结合，从而有效抑制大鼠OX40L的T细胞共刺激活性。使用ATM-2和抗大鼠OX40单克隆抗体（MRC OX40）进行的流式细胞术分析表明，用固定化抗CD3单克隆抗体刺激可诱导脾脏CD4(+) T细胞表达OX40，而静止或活化的T细胞上不表达OX40L。用脂多糖（LPS）刺激后，脾脏B细胞表达OX40L，但腹膜巨噬细胞上不表达。有趣的是，脾脏树突状细胞（DC）组成性表达OX40L，LPS刺激可使其进一步上调。ATM-2可显著抑制脾脏DC对抗CD3刺激的大鼠CD4(+) T细胞增殖和细胞因子（IL-2、IFN-γ、IL-10和IL-13）产生的强大共刺激活性。这些结果表明，OX40L在专职抗原呈递细胞（APC）上表达，可能通过大鼠系统中的T-B相互作用参与体液免疫反应，并通过T-DC相互作用参与细胞免疫反应。
