Research on the correlation of mannose binding lectin (MBL) with diabetes MBLlitus and arteriosclerosis

我们通过凝胶过滤检查了已知MBL基因型的血清，并使用MBL的ELISA评估了它们的洗脱模式，并鉴定了两种MBL形式，高分子量形式和低分子量形式。通过在个体血清中识别一种或两种形式，出现了三种类型的模式：I型由高分子形式组成；2型，低分子形式；第三种类型，两种都有。1型、2型和3型分别对应于野生型（a / a）、密码子54纯合突变（BIB）和杂合子（a /B）。与甘露聚糖和MASP-1/3的结合仅以高分子形式发生。明显的MBL缺陷实际上并不代表MBL分子的缺陷，而是存在循环低聚突变的MBL，其功能受损。研究了MBL与多种免疫球蛋白的结合能力。在免疫球蛋白中，有相当一部分骨髓瘤IgA与MBL具有结合能力，但多数表现为极弱或无结合能力。IgAs与MBL的结合被证实是通过碳水化合物部分。与MBL结合能力弱或无结合能力的免疫球蛋白在唾液酸酶和半乳糖苷酶处理后与MiIBL发生反应，这表明在与MBL反应中暴露甘露糖和/或n-乙酰氨基葡萄糖是必要的。提示某些具有特殊糖结构的IgAs可能参与了与mbl沉积相关的IgA肾病的发生。研究了口服四氯化碳对氧化应激大鼠血清MBL水平的影响。虽然由于四氯化碳的肝脏容量的原因，MBL在给药后立即急剧下降，但在2 ~ 3天内恢复到原来的水平。在使用四氯化碳的情况下，没有观察到氧化应激导致MBL水平的快速升高。

We examined sera of known MBL genotype by gel-filtration and assesed their elution patterns using an ELISA for MBL and identified two MBL forms, a high molecular weight form and a lower molecular weight form. By the identification of either or both forms in individual sera, three types of patterns emerged: type I consisted of a high molecular form; type 2, of a low molecular form; and type 3, of both forms. Types 1, 2 and 3 corresponded, respectively, to a wild type (A/A), a homozygous mutation at codon 54 (BIB) and their heterozygote (A/B). Binding to mannan and MASP-1/3 occurred exclusively with the high molecular form. An apparent MBL deficiency does not in fact represent a deficiency in MBL molecules but rather the presence of circulating oligomeric mutant MBL with impaired function.Binding ability of MBL with various immunoglobulins was investigated. Among the immunoglobulins, quite a few myeloma IgA showed binding capacity with MBL, and most of them exhibited very weak or no capacity. The binding of the IgAs with MBL was confirmed to be through carbohydrate moieties. The immunoglobulins with weak or no binding capacity with MBL became reactive with MiIBL when they were treated with sialidase and galactosidase, indicating that exposure of mannose and/or n-acetylglucosamine is necessary in the reaction with MBL. It was suggested that some IgAs with some special sugar constitution might play a part in an occur-rence of IgA nephropathy associated with MBL-deposition.The change of the serum MBL level in oxidative stress by oral administration of carbon tetrachioride to rat was inves-tigated. Although the MBL level was severely decreased immediately after the administration possi-bly due to hepatic capacity of carbon tetrachloride, it recovered to the previous level within two to three days. Rapid elevation of MBL level by oxidative stress was not observed in the case using carbon tetrachloride.