The effect of a proteinase trapping agent, alpha-2-macroglobulin, on the activity of immuno- and neural cells

α -2巨球蛋白是一种可变的蛋白酶抑制剂，可以通过一种称为陷阱机制的独特机制抑制多种内源性蛋白酶的活性。该机制假定，α -2- m“诱饵区”肽键的断裂触发了一系列分子内反应，最终导致包裹在蛋白酶上的α -2- m结构发生全局变化。饵区水解速率及其后续反应（包括结构变化）的测定一直是捕集器机理研究中的一个关键问题。在这项研究中，我们首次成功地确定了鱼饵区裂解速率和全球结构变化速率。作为本研究的下一个成就，我们验证了我们的假设，即α -2- m可以作为肽疫苗的有效载体，用于抗原提呈细胞（如巨噬细胞）。开发多肽疫苗的概念是为了消除源自生物材料的常规疫苗的危险副作用。化学合成的多肽被用来代替传统的疫苗，但这种多肽的低抗原性应该得到加强。我们提出合成肽可以与α -2- m结合并给药给宿主动物。这种缀合物可以通过受体介导的内吞作用被巨噬细胞有效地吸收，并最终激活高水平的抗体产生。这类实验在本研究中的应用前景十分广阔。本研究考察了α -2- m对培养神经元的作用，结果证实了α -2- m对神经突的延伸作用。脑组织中α -2- m及其受体的存在已被证实，表明观察到的蛋白质活性可能在大脑发育中具有重要的生理意义。

Alpha-2-macroglobulin is a varsatile protease inhibitor that can inhibits the activity of a large variety of endoproteinases by a unique mechanism called the trap mechanism. The mechanism assumes that the cleavage of peptide bonds in the "bait region" of alpha-2-M triggers off a gequential intra-molecular reactions that finally causes a global change in the structure of alpha-2-M entrapping the proteinase. Determination of the rate of bait region hydrolysis and those of subsequent reactions including the structural change has been a key lsssue in the study of trap mechanism. In this study we have been successful in determining the rate of bait region cleavage and that of the global structural change for the first time.As the next accomplishment in this study, we tested our hypothesis that alpha-2-M can be used as an efficient carrier of peptide vaccines to antigen presenting cells such as macrophages. The peptide vaccine concept has been developed to eliminate the hazardous side effects of conventional vaccines derived from bio-materials. Chemically synthesized peptides are used in place of conventlonal vaccines but the low antigenicity of such peptides should be augmented. WE proposed that synthetic peptides can be conjugated to alpha-2-M and administered to host animals. The conjugate can be efficiently taken up by macrophages via receptor mediated endocytosis and eventually activates a high degree of antibody production. The of such experiment in this study has been very promising.The effect of alpha-2-M the cultured neurons has been examined in this study and the result was positlvely interpreted to show the neurite extension effect of alpha-2-M.The presence of alpha-2-M and its receptor in the brain tissue has been confirmed suggesting the observed activity of the protein could be physiologically important in the brain development.