A study in the mechanism of cell fusion and giant cell fromation in skin diseases

为了阐明皮肤多核巨细胞形成的机制，我们研究了融合调节蛋白-1 （fusion regulatory protein-1, FRP-1）在全身和皮肤慢性炎症性疾病皮损中的表达。使用抗FRP-1单克隆抗体进行免疫组织学检查发现，在这些皮肤病早期病变的炎症浸润中，膜性表达的FRP-1增加。根据合胞体的形成，免疫反应性FRP-1的表达明显下调，成熟巨细胞中不再检测到膜FRP-1。随后，用功能性抗FRP-1单克隆抗体脉冲体外培养的单核细胞诱导免疫反应性FRP-1表达，其表达随时间增加直至合胞体形成。而细胞膜上的frp -1在细胞融合后表达明显下调，在形成的巨细胞中不再被检测到。这些结果证实了活跃的FRP-1膜蛋白参与单核细胞合胞体的形成，而细胞膜FRP-1的下调是超大巨细胞形成的有效保护机制。

To declare the mechanism of dermal multinuclear giant cells formation, we investigated fusion regulatory protein-1 (FRP-1) expression in the skin lesions of the systemic and cutaneous chronic inflammatory diseases. Immunohistological investigation using anti-FRP-1 monoclonal antibody revealed augmentation of membranous expression of FRP-1 in the inflammatory infiltrates of the early phaselesion of these skin diseases. According to the syncytium formation, the immunoreactive FRP-1 expression was down regulated significantly, and the membrane FRP-1 was no more detective in the matured giant cells. Subsequent, invitro cultured monocytes pulsed with a functional anti-FRP-1 monoclonal antibody induced immunoreactive FRP-1 expression, and its expression was augmented time dependently until the syncytium formation. In contrast, membrane FRP-1expression was downregulated significantly after cell fusion, and it was no more detective in the formed giant cells. These results confirmed involvement of the active FRP-1 membrane protein in the syncytium formation of monocytes and downregulation of membrane FRP-1 is a potent protective mechanism for over-sized giant cell formation.