Calcium-dependent lectin, which acts as a pattern recognition receptor that initiates the lectin pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system (PubMed:10679061, PubMed:14707097, PubMed:15804047, PubMed:17215869, PubMed:25344472, PubMed:8576206). Specifically recognizes and binds carbohydrates on the pathogen surface, activating the MASP1 serine protease and initiating the proteolytic cascade of the lectin complement pathway (PubMed:14707097). Specifically binds N- Acetylglucosamine (GlcNAc), as well as phosphocholine and lipoteichoic acid moieties on the surface of pathogens (PubMed:14707097, PubMed:17215869, PubMed:25344472, PubMed:8576206). Enhances phagocytosis of S.typhimurium by neutrophils, suggesting an opsonic effect (PubMed:8576206). {ECO:0000269|PubMed:10679061, ECO:0000269|PubMed:14707097, ECO:0000269|PubMed:15804047, ECO:0000269|PubMed:17215869, ECO:0000269|PubMed:25344472, ECO:0000269|PubMed:8576206}. This is the function of FCN2 (ficolin 2, ENSG00000160339).