Lectin Pathway

The lectin pathway is initiated when one of the pattern recognition receptors (PRRs) binds to pathogen-associated molecular patterns (PAMPs) (D-mannose, N-acetyl-D-glucosamine, or acetyl groups), on the surface of invading microorganisms or apoptotic/necrotic cells. The well-characterized PRRs include mannose-binding lectin (MBL), ficolins and collagen-containing soluble C-type lectins (collectins), such as kidney collectin-11 (CL-K1). These circulated lectins are complexed with serine proteases named MBL-associated serine proteases (MASPs), comprising MASP-1, -2, and -3. The enzymatic cascade is really started after the binding of MBL/MASPs, CL-K1/MASPs, or ficolin/MASPs complexes to their targets.