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

为了阐明真皮多核巨细胞形成的机制，我们研究了融合调节蛋白-1（FRP-1）在全身性和皮肤慢性炎症性疾病皮损中的表达。免疫组化研究显示，FRP-1的膜表达增强的早期阶段这些皮肤病的炎症浸润。结合胞体的形成，在成熟的巨细胞中，FRP-1的表达明显下调，膜FRP-1的表达消失。随后，体外培养的单核细胞脉冲与功能性抗FRP-1单克隆抗体诱导免疫反应性FRP-1的表达，其表达增强时间依赖性，直到合胞体形成。细胞融合后膜FRP-1表达明显下调，在形成的巨细胞中不再检测到FRP-1表达。这些结果证实了活性FRP-1膜蛋白参与单核细胞的合胞体形成，并且膜FRP-1的下调是过大的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.