Heterogeneity of MBL–MASP complexes

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• 作者：Karine R. Mayilyan ; Julia S. Presanis ; James N. Arnold ; Krishnan Hajela and Robert B. Sim
• 刊名：Molecular Immunology
• 出版年：2006
• 出版时间：March 2006
• 年：2006
• 卷：43
• 期：8
• 页码：1286-1292
• 全文大小：244 K

文摘

In order to study aspects of the stoichiometry and composition of human MBL–MASP complexes in the population, MBL–MASP complexes were bound from sera of 152 healthy individuals onto mannan-coated microtitre plates. Bound mannan-binding lectin (MBL) was measured by ELISA, and the enzyme activities of MBL-bound MASP-1 and MASP-2 were measured by an amidolytic assay and a C4 fixation assay, respectively. MASP-1 activity correlated with MBL concentration, as did MASP-2 activity (in both cases: p < 0.0001). This is expected since MASP-1 and MASP-2 are bound to the mannan via MBL. However, when MASP activities were normalised to MBL concentration (i.e. MASP-1 activity/[MBL], MASP-2 activity/[MBL]) MASP-1 activity was inversely correlated with MASP-2. This means on average that high MASP-1 correlates with low MASP-2 and vice-versa, and confirms the hypothesis that native MBL–MASP complexes on average do not have fixed MBL-(MASP-1)-(MASP-2) stoichiometry. The findings are consistent with separate populations of MBL–MASP-1 complexes and MBL–MASP-2 complexes, the concentrations of which show wide inter-individual variation.