Biological variations of MASP-3 and MAp44, two splice products of the MASP1 gene involved in regulation of the complement system
Biological variations of MASP-3 and MAp44, two splice products of the MASP1 gene involved in regulation of the complement system
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DOI：
10.1016/j.jim.2010.07.006
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发表时间：
2010-09-30
影响因子：
2.2
通讯作者：
Thiel, Steffen
中科院分区：
文献类型：
--
作者：
Degn, Soren E.;Jensen, Lisbeth;Thiel, Steffen
补体的凝集素途径是先天免疫系统的一部分。补体激活模式识别分子（我们建议缩写为CAPREM）甘露聚糖结合凝集素（MBL）和三种纤维胶凝蛋白（H-、L-和M-纤维胶凝蛋白）与MBL相关丝氨酸蛋白酶（MASP-1、-2和-3）和两种其他蛋白（MAp 19和MAp 44，也分别称为sMAP和MAP-1）复合循环。当MBL或纤维胶凝蛋白识别微生物或改变的自身组分时，MASP的活化增强，导致补体系统的活化。MASP-1。MASP-3和MAp 44都是由MASPl基因编码的三种。MASP-1和MASP-3共有五个结构域（构成所谓的A链），但具有独特的蛋白酶结构域（B链）。MAp 44与MASP-1和MASP-3共享前四个结构域，随后是17个独特的C-末端氨基酸残基。因此，需要对MASP-3的蛋白酶结构域和MAp 44的17个C-末端氨基酸进行测定以特异性地测量这些蛋白质，并且在此我们提出了对MASP-3和MAp 44的此类测定。用与三种蛋白质的共同结构域（CCP 1）反应的单克隆抗体（5 F5）捕获MASP-3，并用对MASP-3蛋白酶结构域的C-末端部分特异的单克隆抗体（38.12.3）开发测定法。用与MAp 44的C末端反应的单克隆抗体（2D 5）捕获MAp 44，然后用单克隆抗CCP 1抗体（4 H2）进行测定开发。使用血清的Superose 6凝胶渗透色谱，在复合物中发现MASP-3和MAp 44，其分别在对应于600-800 kDa和500-700 kDa的位置洗脱。供体血清（N = 200）中MASP-3的水平为对数正态分布，中值为5.0 μ g/ml（范围：1.8-10.6 μ g/ml），MAp 44的相应值也为对数正态分布，为1.7 μ g/ml（范围：0.8-3.2 μ g/ml）。对于MASP-3，低、中和高水平内部对照的试验间变异系数分别为4.9%、6.9%和3.9%（N = 12）。对于MAp 44，相应的试验间CV为7.6%、62%和7.0%（N = 12）。MASP-3水平在出生时较低，并在前6个月内达到成人水平，而MAp 44水平在前6个月期间略有下降。与接受大手术的患者的急性期反应同时发生，两种蛋白质的水平在1-2天内略有下降，但MAp-3在另外2天内恢复至基线值，而MAp 44仅在第30天左右达到基线值。因此，这两种蛋白质都不表现为经典的急性期蛋白。(C)2010爱思唯尔有限公司版权所有。
The lectin pathway of complement is part of the innate immune system. The complement-activating pattern-recognition molecules (for which we suggest the abbreviation CAPREMs) mannan-binding lectin (MBL) and the three ficolins (H-, L- and M-ficolin) circulate in complexes with MBL-associated serine proteases (MASP-1, -2 and -3) and two additional proteins (MAp19 and MAp44, also termed sMAP and MAP-1, respectively). When MBL or ficolins recognize a microorganism or altered self components, activation of the MASPs ensues, leading to the activation of the complement system. MASP-1. MASP-3 and MAp44 are all three encoded by the MASP1 gene. MASP-1 and -3 share five domains (constituting the so-called A-chain), but have unique protease domains (B-chains). MAp44 shares the first four domains with MASP-1 and MASP-3, followed by 17 unique C-terminal amino acid residues. Thus, assays for the protease domain of MASP-3 and for the 17 C-terminal amino acids of MAp44 are required to measure these proteins specifically and here we present such assays for MASP-3 and MAp44. MASP-3 was captured with a monoclonal antibody (5F5) reacting with a common domain of the three proteins (CCP1) and the assay was developed with a monoclonal antibody (38.12.3) specific for the C-terminal part of the MASP-3 protease domain. MAp44 was captured with a monoclonal antibody (2D5) reacting with the C-terminus of MAp44 followed by assay development with a monoclonal anti-CCP1 antibody (4H2). Using Superose 6 gel permeation chromatography of serum, MASP-3 and MAp44 were found in complexes, which eluted in positions corresponding to 600-800 kDa and 500-700 kDa, respectively. The level of MASP-3 in donor sera (N = 200) was log-normally distributed with a median value of 5.0 mu g/ml (range: 1.8-10.6 mu g/ml), and the corresponding value for MAp44, also log-normally distributed, was 1.7 mu g/ml (range: 0.8-3.2 mu g/ml). For MASP-3, the inter-assay coefficients of variation of low, intermediate and high level internal controls were 4.9%, 6.9% and 3.9% (N = 12). For MAp44, the corresponding inter-assay CVs were 7.6%, 62%, and 7.0% (N = 12). MASP-3 levels were low at birth and reached adult levels within the first 6 months, whereas MAp44 levels fell slightly during the first 6 months. Concomitant with the acute phase response in patients undergoing major surgery, levels of both proteins fell slightly over 1-2 days, but whereas MASP-3 recovered to baseline values over another 2 days, MAp44 only reached baseline values at around day 30. Thus, neither of the two proteins behaves as a classical acute phase protein. (C) 2010 Elsevier B.V. All rights reserved.