Lipid and Lipoproteoglycan Hemagglutinins from Nereis

人们对脂类作为特定识别分子的作用知之甚少，尽管脂类的血凝作用已经有过几次报道。从河豚体腔液和体腔细胞中分离得到的脂类和脂蛋白多糖凝集素的组成、性质和功能将阐明它们在无脊椎动物免疫反应中的作用以及它们识别特定细胞受体的可能性。在对沙蚕磷脂凝集素的研究中发现，人工合成的不饱和磷脂酰乙醇胺的陈化制剂为血凝素。这一观察开辟了第二条途径，以获得可观数量的特定类别的脂质凝集素，并定义赋予活性的结构要求。化学分析、层析(2D-TLC、HPLC)和光谱分析(MS、FTIR和核磁共振)正被用于表征这些凝集素的组成和结构。红细胞(RBC)的结合和抑制谱以及酶修饰的RBC的使用表明结合的范围和特异性。这些凝集素对其他类型细胞的影响正在确定中。光学和电子显微镜(EM)被用来显示这些相互作用，并且将使用EM和31P核磁共振(磷脂凝集素)来研究脂质聚集体的结构。敏感细胞上的特定受体将被分离出来。来自这些研究的信息将确定在特定细胞表面以二价或多价方式作用的外源脂类的结构和聚集状态，建议正在发生何种结合，预测其他天然或合成脂类的行为，并建议作为试剂的脂类在细胞操作中的使用方法。脂类介导的细胞-表面相互作用很少受到关注，尽管零星的报道表明脂类可能起到这样的作用。进一步研究脂质和脂蛋白多糖凝集素在海洋蠕虫Nereis免疫样防御机制中的作用，有望为脂质在特定细胞识别现象中更一般的作用提供重要的新见解。

Little is known about the roles of lipids as specific recognition molecules although hemagglutination by lipids has been reported on several occasions. The composition, properties, and functions of lipid and lipoproteoglycan agglutinins, which have been isolated from Nereis coelomic fluid and coelomocytes, will elucidate their roles in the invertebrate immune response and their potential for recognizing specific cell receptors. While studying the phospholipid agglutinins from Nereis, it was discovered that aged preparations of synthetic unsaturated phosphatidylethanolamines are hemagglutinins. This observation opens up a second route to obtain appreciable quantities of a specific class of lipid agglutinin and to define the structural requirements which confer activity. Chemical analysis, chromatography (2D-TLC, HPLC) and spectroscopy (MS, FTIR and NMR) are being used to characterize the components and structures of these agglutinins. Red blood cell (RBC) binding and inhibitor profiles and the use of enzymically-modified RBC indicate range and specificity of binding. The effects of these agglutinins on other kinds of cells are being determined. Light and electron microscopy (EM) are being used to visualize these interactions and the structures of the lipid aggregates will be studied using EM and 31 P NMR (for phospho-lipid agglutinins). Specific receptors on susceptible cells will be isolated. The information from these studies will define the structures and aggregation state of exogenous lipids which act in a bi- or multi-valent manner on specific cell surfaces, suggest what kind of binding is taking place, predict the behavior of other natural or synthetic lipids, and suggest ways in which lipids, as reagents, can be used in cell manipulation. Cell-surface interactions mediated by lipids have received very little attention, although scattered reports have suggested that lipids may play such a role. Further study of the role of lipids and lipoproteoglycan agglutinins in the immune-like defense mechanisms of the marine worm, Nereis, promises to provide important new insights into the more general role of lipids in specific cellular recognition phenomena.