A journey through the lectin pathway of complement-MBL and beyond

Area of Science:

• Immunology
• Complement System Biology

Background:

• Soluble pattern recognition molecules (PRMs) like MBL, collectins, and ficolins are crucial for innate immunity and tissue homeostasis.
• These PRMs bind pathogen structures and self-antigens, interacting with MASP proteases to modulate immune responses.

Purpose of the Study:

• To review the characteristics of PRMs within the lectin complement pathway.
• To highlight the diverse roles of these molecules beyond pathogen recognition, including tissue homeostasis and disease modulation.

Main Methods:

• Literature review summarizing existing research on lectin pathway molecules.
• Analysis of protein interactions, expression patterns, and functional roles.

Main Results:

• MBL, collectins, and ficolins interact with MASP proteases (MASP-1, -2, -3), initiating lectin pathway activation.
• MASPs also regulate coagulation, bradykinin release, and endothelial/platelet activation.
• Genetic variants in these molecules are linked to various diseases, and mutations in collectin-11 or MASP-3 cause severe developmental syndromes.

Conclusions:

• The lectin pathway molecules and their associated MASP proteases have multifaceted roles in immunity, homeostasis, and disease.
• Their involvement extends to embryonic development, indicating a broader scope for complement system functionality.