Molecular mechanism of axonal regeneration-Role of receptor of repulsive factor for neurite elongation-

成熟哺乳动物中枢神经系统轴突损伤后一般不能再生。尽管这种再生失败的原因尚不清楚，但一些证据表明，这是由于少突胶质细胞不允许轴突伸长。近年来，来自少突胶质细胞的排斥因子被认为是研究这一问题的重要因素。结果表明，在这些分子上应用单克隆抗体可使生长锥收缩或避免与少突胶质细胞接触。这一发现提示排斥因子受体的存在。本项目的目的是通过鉴定这种可能的受体来阐明轴突再生的机制。作为策略，我们采用单克隆抗体法和功能筛选法。我们培养了鸡胚背根神经节。用凝胶电泳或柱层析法分离生长锥，匀浆，分离生长锥特异性组分。用这种抗原使人免疫。脾细胞与骨髓瘤杂交，筛选分泌特异性抗体的杂交瘤。我们利用杂交瘤产生的单克隆抗体，选择产生抗体使生长锥缩回的克隆。我们开发了延时视频分析系统，并在本研究中有效地使用了该系统。

Axons in the central nervous system of mature mammals generally fail toregenerate following injury. Although the reason for this regenerative failure remains unknown, several lines of evidence suggest that it is dueto non-permissiveness of oligodendrocytes for axonal elongation. In recentyears, repulsive factors derived from oligodendrocytes have been thought to be important for studying this issue. It was shown that application of monoclonal antibodies to these molecules made growth cones to retract or avoid on contact with oligodendrocytes. This finding suggests the existence of receptor for repulsive factors.The aim of this project was to elucidate the mechanisms of axonal regeneration by identifying this presumable receptor. As a strategy, we used monoclonal antibody method and functional screening method.We cultured dorsal root ganglia of the chick embryo. Growth cones were isolated, homogenized and growth cone-specific fractions were isolated by gel electrophoresis or column chromatography. Mise were immunized with this antigen. Spleen cells were hybridized with myeloma and hybridomas secreting specific antibodies were screened. We applied monoclonal antibodies produced by the hybridomas and clones whose produced antibodies made growth cones to retract were selected. We have developed time-lapse video analysis system and used this system effectively in the present study.