MBL(Mannose-binding lectin) also known as MBL2 is a member of the collectin family of proteins. MBL plays a key role in innate immunity via activation of the lectin complement pathway. MBL is produced in the liver and circulates in the serum in complexes with MBL-associated serine proteases (MASPS). MBL acts as a pattern recognition receptor and binds carbohydrates on the surface of various microorganisms as well as on dying host cells. MBL recognizes and binds to mannose and N-acetylglucosamine on many microorganisms, including bacteria, yeast, and viruses including influenza virus, HIV and SARS-CoV. This binding activates the classical complement pathway. Deficiencies of this gene have been associated with susceptibility to autoimmune and infectious diseases.