Lipid and Lipoproteoglycan Hemagglutinins from Nereis

脂质作为特异性识别分子的作用知之甚少，尽管脂质引起的血凝已经在一些场合报道过。从沙蚕体腔液和体腔细胞中分离出的脂质和脂蛋白聚糖凝集素的组成、性质和功能，将阐明它们在无脊椎动物免疫应答中的作用以及它们识别特定细胞受体的潜力。在研究海蚕磷脂凝集素时，发现合成不饱和磷脂酰乙醇胺的陈化制剂是血凝素。这一观察结果开辟了第二种途径，以获得可观数量的一类特定的脂质凝集素，并确定赋予活性的结构要求。化学分析，色谱（2D-TLC， HPLC）和光谱（MS， FTIR和NMR）被用来表征这些凝集素的成分和结构。红细胞（RBC）结合和抑制剂谱以及酶修饰红细胞的使用表明了结合的范围和特异性。这些凝集素对其他类型细胞的作用正在被确定。光镜和电子显微镜（EM）被用于可视化这些相互作用，脂质聚集体的结构将使用EM和31p NMR（用于磷脂-脂质凝集素）进行研究。易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定义外源性脂质在特定细胞表面以双价或多价方式起作用的结构和聚集状态，提示正在发生何种结合，预测其他天然或合成脂质的行为，并建议将脂质作为试剂用于细胞操作的方法。脂质介导的细胞表面相互作用很少受到关注，尽管零散的报道表明脂质可能起着这样的作用。进一步研究脂质和脂蛋白聚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的更普遍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.