Oshima H, Nakano H, Nohara C, Kobata T, Nakajima A, Jenkins N A, Gilbert D J, Copeland N G, Muto T, Yagita H, Okumura K
Department of First Surgery, Faculty of Medicine, University of Tokyo, Japan.
Int Immunol. 1998 Apr;10(4):517-26. doi: 10.1093/intimm/10.4.517.
CD27, a member of the tumor necrosis factor (TNF) receptor family, has been implicated in T cell activation, T cell development and T-dependent antibody production by B cells. Its ligand CD70 has been identified only in humans, and, thus, physiological and pathological roles of the CD70-CD27 interaction remain to be determined in an experimental animal system. In the present study, we identified murine (m) CD70 by molecular cloning, and characterized its expression and function by generating an anti-mCD70 mAb. The mCD70 cDNA encoded a type II transmembrane glycoprotein of the TNF family, having 56.5% identity to the human CD70 amino acid sequence. The mCd70 gene was assigned in the central region of chromosome 17. To explore the expression and function of mCD70, we generated cDNA transfectants and anti-mCD70 mAb (FR70), which inhibited binding of a murine CD27-Fc fusion protein (mCD27-Ig) to mCD70 transfectants. FR70, as well as mCD27-Ig, immunoprecipitated a 30-33 kDa surface protein from A20 and mCD70-P815 cells but not from P815 cells. The mCD70 transfectants exhibited a potent co-stimulatory activity for anti-CD3-stimulated T cell proliferation, which was blocked by FR70 far more efficiently than mCD27-Ig. FR70 also abrogated the CD28-independent co-stimulatory activity of A20 cells. The expression of mCD70 was detected on splenic T cells after stimulation with anti-CD3 and anti-CD28 mAb, and on splenic B cells after stimulation with anti-CD40 mAb. Cross-linking of surface Ig by anti-IgM mAb did not induce the mCD70 expression but enhanced the anti-CD40-induced mCD70 expression on splenic B cells. These results suggest a contribution of CD70 to murine T-B cognate interaction as proposed in the human system. FR70 will be useful for further investigating the physiological and pathological roles of the CD70-CD27 interaction in T cell development, T-dependent antibody production and various disease models in the murine system.
CD27是肿瘤坏死因子（TNF）受体家族的成员，与T细胞活化、T细胞发育以及B细胞产生T细胞依赖性抗体有关。其配体CD70仅在人类中被鉴定出来，因此，CD70-CD27相互作用的生理和病理作用仍有待在实验动物系统中确定。在本研究中，我们通过分子克隆鉴定了小鼠（m）CD70，并通过制备抗mCD70单克隆抗体来表征其表达和功能。mCD70 cDNA编码一种TNF家族的II型跨膜糖蛋白，与人CD70氨基酸序列具有56.5%的同一性。mCd70基因定位于17号染色体的中央区域。为了探究mCD70的表达和功能，我们构建了cDNA转染细胞系并制备了抗mCD70单克隆抗体（FR70），该抗体可抑制小鼠CD27-Fc融合蛋白（mCD27-Ig）与mCD70转染细胞系的结合。FR70以及mCD27-Ig能从A20和mCD70-P815细胞中免疫沉淀出一种30 - 33 kDa的表面蛋白，但不能从P815细胞中沉淀出来。mCD70转染细胞系对抗CD3刺激的T细胞增殖表现出强大的共刺激活性，FR70对其的阻断效率远高于mCD27-Ig。FR70还消除了A20细胞不依赖CD28的共刺激活性。在用抗CD3和抗CD28单克隆抗体刺激后，在脾T细胞上检测到了mCD70的表达，在用抗CD40单克隆抗体刺激后，在脾B细胞上检测到了mCD70的表达。用抗IgM单克隆抗体交联表面免疫球蛋白不会诱导mCD70的表达，但会增强抗CD40诱导的脾B细胞上mCD70的表达。这些结果表明，正如在人类系统中所提出的那样，CD70对小鼠T - B同源相互作用有贡献。FR70将有助于进一步研究CD70-CD27相互作用在小鼠系统中T细胞发育、T细胞依赖性抗体产生及各种疾病模型中的生理和病理作用。
