Final answer:
The lectin pathway is initiated by mannose-binding lectin (MBL) and MASP-2, which differentiates it from the classical and alternative complement pathways.
Step-by-step explanation:
The lectin pathway is initiated by the interaction of mannose-binding lectin (MBL) with specific carbohydrate patterns on the surface of a pathogen. Mannose-binding lectin-associated serine proteases (MASP-2) bind to MBL leading to complement activation. This pathway is distinct from the classical pathway, which requires antibody binding to the antigen, and the alternative pathway, which is spontaneously activated by C3.