Mannan binding lectin (MBL) belongs to the collectin family of innate immune defense proteins, which binds to an array of carbohydrate patterns on pathogen surfaces.1, 2 Collectin family members share common structural features: a cysteine rich amino-terminal domain, a collagen-like region, an α-helical coiled-coil neck domain and a carboxy terminal C-type (Ca++-dependent ) lectin or carbohydrate recognition domain (CRD). MBL homotrimerizes to form a structural unit joined by N-terminal disulfide bridges. These homotrimers further associates into oligomeric structures of up to 6 units. Whereas two forms of MBL proteins (MBL-1, also known as S-MBP or MBL-A and MBL-2, also known as L-MBP or MBL-C) exist in rodents and other animals, only one functional MBL protein is present in humans. Mouse MBL-1 shares about 52% and 60% amino acid sequence identity with mouse MBL-2 and human MBL, respectively.
In mouse, MBL-1 and MBL-2 are the only collectins that can activate complement via the lectin complement pathway.1, 2 Serumoligomeric MBL associates with MBL-associated serine protease (MASP) proenzymes. The MBL-MASP proenzyme complex preferentially interact with sugar patterns containing mannose, glucose, L-fucose, or N-acetyl-glucosamine present at a terminal nonreducing postion on the cell surface of various pathogens and certain tumor cells. This interaction induces pro-enzyme activation and the triggering of the complement cascade, resulting in opsonization and pathogen removal via humoral and cellular immune responses. MBL does not recognize self-components or glycoproteins from other higher animals due to the presence ofterminal sialic acid or galactose that interrupts the repeating carbohydrate structures.3 A number of membrane receptors for MBL, including C1q phagocytic receptor (C1qRp), calreticulin (also known as C1qR), and CR1 (CD35), have been described. Interactions with these receptors may also be important in stimulating phagocytosis,1, 2 Mouse MBL-1 and MBL-2 are produced primarily in the liver and are secreted into the blood stream. In addition, mouse MBL-1 is also expressed in lung, kidney and testis while MBL-2 is expressed in kidney, thymus and small intestine.1, 4, 5
Source:A DNA sequence encoding the mature mouse MBL-1 (Mannan Binding Lectin-1), amino acid residues Ser18-Ala239 (Uemura, K. et al., 2002, J. Immunol. 169:6945-6950) was fused to the signal peptide of human CD33. The protein was expressed in a mouse myeloma cell line, NS0.
Molecular Mass:The mature recombinant mature mouse MBL-1, generated by proteolytic removal of the signal peptide, is an oligomeric protein. Based on N-terminal sequencing, the recombinant mouse MBL-1 begins with Ser 18 and has a calculated monomeric molecular mass of approximately 24kD. The recobmbinant mouse MBL-1 migrates as an approximately 29kD protein in SDSPAGE under reducing conditions.
Activity:Measured by its ability to bind with Mannan.
Storage and Stability:Lyophilized and reconstituted products are stable for 6 months after receipt at -20°C. Reconstitute with sterile PBS containing 0.1% HSA or BSA. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
