Meier H L, Flowers B, Silverberg M, Kaplan A P, Newball H H
Am J Pathol. 1986 Apr;123(1):146-54.
Passively sensitized human lung fragments were shown to release a protease by an IgE-dependent mechanism which can cleave human Hageman factor (Coagulation Factor XII). This enzyme, lung Hageman factor cleaving factor, was partially purified by ion exchange chromatography and gel filtration and was shown to be a serine protease with an apparent molecular weight of 12,000-13,000. This protease appears to be unrelated to any known activator of Hageman factor by molecular weight and inhibition profile and was shown to be distinct from an IgE-dependent prekallikrein activator, as well as the kininogenase activity defined as basophil kallikrein of anaphylaxis. Although it appears marginally capable of activating Hageman factor, it rapidly cleaves and inactivates the activated form so that the net effect is a loss of activatable Hageman factor. The result suggests that diminished levels of Hageman factor that may be seen associated with IgE-dependent reactions can be due to digestion and depletion rather than activation, and other criteria for activation of the contact system must be employed.
被动致敏的人肺组织碎片经证实可通过一种IgE依赖机制释放一种蛋白酶，该蛋白酶能够裂解人Hageman因子（凝血因子XII）。这种酶，即肺Hageman因子裂解因子，通过离子交换色谱法和凝胶过滤法进行了部分纯化，结果显示它是一种丝氨酸蛋白酶，表观分子量为12,000 - 13,000。从分子量和抑制谱来看，这种蛋白酶似乎与任何已知的Hageman因子激活剂无关，并且已证实它不同于IgE依赖的前激肽释放酶激活剂，也不同于被定义为过敏反应中嗜碱性粒细胞激肽释放酶的激肽原酶活性。尽管它似乎略微能够激活Hageman因子，但它会迅速裂解并使激活形式失活，因此最终结果是可激活的Hageman因子减少。该结果表明，与IgE依赖反应相关的Hageman因子水平降低可能是由于消化和消耗而非激活所致，必须采用其他接触系统激活标准。
