Dommett R M, Klein N, Turner M W
Infectious Diseases and Microbiology Unit, Institute of Child Health, UCL, 30 Guilford Street, London WC1N 1EH, UK.
Tissue Antigens. 2006 Sep;68(3):193-209. doi: 10.1111/j.1399-0039.2006.00649.x.
The human collectin, mannose-binding lectin (MBL), is an important protein of the humoral innate immune system. With multiple carbohydrate-recognition domains, it is able to bind to sugar groups displayed on the surfaces of a wide range of microorganisms and thereby provide first-line defence. Importantly, it also activates the complement system through a distinctive third pathway, independent of both antibody and the C1 complex. Three single point mutations in exon 1 of the expressed human MBL-2 gene appear to impair the generation of functional oligomers. Such deficiencies of functional protein are common in certain populations, e.g. in sub-Saharan Africa, but virtually absent in others, e.g. indigenous Australians. MBL disease association studies have been a fruitful area of research and implicate a role for MBL in infective, inflammatory and autoimmune disease processes. Overall, there appears to be a genetic balance in which individuals generally benefit from high levels of the protein. However, in certain situations, reduced levels of circulating MBL may be beneficial to the host and this may explain the persistence of the deleterious gene polymorphisms in many population groups.
人类凝集素甘露糖结合凝集素（MBL）是体液固有免疫系统的一种重要蛋白质。它具有多个碳水化合物识别结构域，能够结合多种微生物表面呈现的糖基，从而提供一线防御。重要的是，它还通过一条独特的第三条途径激活补体系统，该途径独立于抗体和C1复合物。表达的人类MBL-2基因外显子1中的三个单点突变似乎会损害功能性寡聚体的生成。这种功能性蛋白质的缺陷在某些人群中很常见，例如在撒哈拉以南非洲，但在其他人群中几乎不存在，例如澳大利亚原住民。MBL疾病关联研究一直是一个富有成果的研究领域，并暗示MBL在感染性、炎症性和自身免疫性疾病过程中发挥作用。总体而言，似乎存在一种遗传平衡，在这种平衡中，个体通常从高水平的该蛋白质中受益。然而，在某些情况下，循环MBL水平降低可能对宿主有益，这可能解释了许多人群中有害基因多态性的持续存在。
