MannoseBindungsspezifität

Mannose-binding lectin (MBL), also known as mannose-binding protein (MBP), is a soluble pattern recognition molecule that plays a crucial role in the innate immune system. It belongs to the collectin family of proteins, characterized by a collagen-like region and a C-type lectin domain. MBL circulates in the blood and is produced primarily by the liver. Its main function is to recognize and bind to specific carbohydrate patterns, particularly mannose and N-acetylglucosamine, found on the surface of various microorganisms, including bacteria, fungi, and some viruses. This binding is dependent on calcium ions.

Upon binding to a pathogen, MBL can initiate an immune response through several mechanisms. It can directly activate the complement system, a cascade of proteins that helps clear pathogens. MBL can bind to complement component C1q, thereby initiating the lectin pathway of complement activation. Alternatively, MBL can act as an opsonin, coating the surface of the microorganism and facilitating its recognition and phagocytosis by immune cells like macrophages and neutrophils. This enhanced phagocytosis helps in the clearance of infectious agents. Furthermore, MBL has been shown to influence other immune cells, such as dendritic cells, potentially bridging innate and adaptive immunity. Genetic variations in the MBL gene are common and can lead to differences in MBL levels in the circulation, which may impact an individual's susceptibility to certain infections.