Wang X, Kumanogoh A, Watanabe C, Shi W, Yoshida K, Kikutani H
Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Blood. 2001 Jun 1;97(11):3498-504. doi: 10.1182/blood.v97.11.3498.
CD100/Sema4D is a 150-kd transmembrane protein that belongs to the semaphorin family. The interaction of CD100 with CD72 is critical for the immune system. In CD100-deficient mice, the production of specific antibodies against T-cell-dependent antigens is severely impaired, but not against T-cell-independent antigens. Here, a functional soluble CD100 protein (sCD100) released from activated lymphocytes is reported. sCD100 was detected in culture supernatants of activated lymphocytes. Either affinity-purified from supernatants of activated T-cells, or produced as a recombinant sCD100 protein consisting of the extracellular region of the mouse CD100 fused to the human IgG1 Fc (CD100-Fc), sCD100 significantly enhanced CD40-induced B-cell responses. Furthermore, sCD100 was detected either in sera of mice immunized with T-cell-dependent antigens, or in sera of MRL/lpr mice, but not in sera of mice immunized with T-cell-independent antigens. A significant correlation was observed between the level of sCD100 and the titer of autoantibodies in the serum of MRL/lpr mice. This study's findings suggest a potential role for sCD100 in immune responses, including production of antibody, and autoimmune diseases. (Blood. 2001;97:3498-3504)
CD100/Sema4D是一种150千道尔顿的跨膜蛋白，属于信号素家族。CD100与CD72的相互作用对免疫系统至关重要。在CD100缺陷小鼠中，针对T细胞依赖性抗原的特异性抗体产生严重受损，但针对T细胞非依赖性抗原的抗体产生不受影响。在此，报道了一种从活化淋巴细胞释放的功能性可溶性CD100蛋白（sCD100）。在活化淋巴细胞的培养上清液中检测到了sCD100。无论是从活化T细胞的上清液中亲和纯化得到，还是作为由小鼠CD100的细胞外区域与人IgG1 Fc融合而成的重组sCD100蛋白（CD100-Fc）产生，sCD100都能显著增强CD40诱导的B细胞反应。此外，在经T细胞依赖性抗原免疫的小鼠血清中或MRL/lpr小鼠血清中检测到了sCD100，但在经T细胞非依赖性抗原免疫的小鼠血清中未检测到。在MRL/lpr小鼠血清中，sCD100水平与自身抗体滴度之间存在显著相关性。这项研究的结果表明sCD100在包括抗体产生在内的免疫反应和自身免疫性疾病中具有潜在作用。（《血液》。2001年；97:3498 - 3504）
