Schwartz Lawrence B, Min Hae-Ki, Ren Shunlin, Xia Han-Zhang, Hu Jiang, Zhao Wei, Moxley George, Fukuoka Yoshihiro
Division of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA.
J Immunol. 2003 Jun 1;170(11):5667-73. doi: 10.4049/jimmunol.170.11.5667.
Tryptase (alpha and beta) levels in serum are used to assess mast cell involvement in human disease. Using cultured cells, the current study examines the hypothesis that protryptase(s) are spontaneously secreted by mast cells at rest, whereas mature tryptase(s) are stored in secretory granules until their release by activated cells. HMC-1 cells have only beta-tryptase genes and the corresponding mRNA. Mono-Mac-6 cells have both alpha- and beta-tryptase genes but preferentially express alpha-tryptase. Mono-Mac-6 cells spontaneously secrete most of their tryptase, which consists of alpha-protryptase, whereas mature tryptase is retained inside these cells. HMC-1 cells also spontaneously secrete most of their tryptase, identified as beta-protryptase, and retain mature tryptase. Skin-derived mast cells retain most of their tryptase, which is mature, and spontaneously secrete protryptase(s). Total tryptase levels in plasma are detectable but no different in healthy subjects with and without the gene for alpha-tryptase, consistent with pro forms of both alpha- and beta-tryptase being spontaneously secreted. Thus, protryptase(s) are spontaneously secreted by resting mast cells, whereas mature tryptase is retained by mast cells until they are activated to degranulate.
血清中的类胰蛋白酶（α和β）水平用于评估肥大细胞在人类疾病中的参与情况。本研究利用培养细胞检验了以下假设：静止的肥大细胞会自发分泌前类胰蛋白酶，而成熟类胰蛋白酶则储存在分泌颗粒中，直至被激活的细胞将其释放。HMC-1细胞只有β-类胰蛋白酶基因及相应的mRNA。单核巨噬细胞6（Mono-Mac-6）细胞同时拥有α-和β-类胰蛋白酶基因，但优先表达α-类胰蛋白酶。Mono-Mac-6细胞会自发分泌其大部分类胰蛋白酶，这些类胰蛋白酶由α-前类胰蛋白酶组成，而成熟类胰蛋白酶则保留在这些细胞内。HMC-1细胞也会自发分泌其大部分类胰蛋白酶，经鉴定为β-前类胰蛋白酶，并保留成熟类胰蛋白酶。皮肤来源的肥大细胞保留其大部分成熟类胰蛋白酶，并自发分泌前类胰蛋白酶。血浆中的总类胰蛋白酶水平可检测到，但在有无α-类胰蛋白酶基因的健康受试者中并无差异，这与α-和β-类胰蛋白酶的前体形式均被自发分泌一致。因此，静止的肥大细胞会自发分泌前类胰蛋白酶，而成熟类胰蛋白酶则被肥大细胞保留，直至它们被激活而脱颗粒。
