Collectins are soluble pattern recognition receptors (PRRs) belonging to the superfamily of collagen containing C-type lectins.
Eight collectins have been identified including mannan-binding lectin (MBL), surfactant protein A (SP-A), surfactant protein D (SP-D), collectin liver 1 (CL-L1), collectin placenta 1 (CL-P1), conglutinin, collectin of 43 kDa (CL-43) and collectin of 46 kDa (CL-46).
These molecules have been implicated as major modulators of the innate immune system where they have a key role in the first line of defense against invading microorganisms by binding to them so macrophages know to dispose of them.[1]
Functionally, collectins are usually trimers with the number of trimeric units differing among the collectin family.
The collectin monomers comprise four structural domains;
The binding of collectins to microbes causes several immune related responses.
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