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Collectins: Collectors of microorganisms for the innate immune system
Author(s) -
Lu Jinhua
Publication year - 1997
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.950190610
Subject(s) - collectin , innate immune system , lectin , biology , microbiology and biotechnology , ficolin , c type lectin , mannan binding lectin , pattern recognition receptor , phagocytosis , receptor , complement system , lectin pathway , glycoprotein , opsonin , immune system , biochemistry , classical complement pathway , immunology
Collections are a group of multimeric proteins mostly consisting of 9–18 polypeptides organised into either ‘bundle‐of‐tulips’ or ‘X‐like’ overall structures. Each polypeptide contains a short N‐terminal segment followed by a collagen‐like sequence and then by a C‐terminal lectin domain. A collectin molecule is assembled from identical or very similar polypeptides by disulphide bonds at the N‐terminal segment, formation of triple helices in the collagen‐like region and clusters of three lectin domains at the peripheral ends of triple helices. These proteins can bind to sugar residues on microorganisms via the peripheral lectin domains and subsequently interact, via the collagen‐like triple‐helices, with receptor(s) on phagocytes and/or the complement system to bring about the killing and clearance of the targets without the involvement of antibodies. The collectins can also bind to phagocyte receptor(s) to enhance phagocytosis mediated by other phagocytic receptors. Lack, or low levels, of collectin expression can lead to higher susceptibility to infections, especially during childhood when specific immunity has not fully developed. Therefore, the collectins play important roles in the enhancement of innate immunity.