Innate immune collectins bind nucleic acids and enhance DNA clearance in vitro.
Collectins are a class of innate immune proteins that opsonize microbes and other ligands via their carbohydrate-recognition domains and enhance their clearance by phagocytes. We hypothesized that collectins, such as pulmonary surfactant protein (SP-) A and D and mannose-binding lectin (MBL), could bind nucleic acid, which is a pentameric sugar-based anionic polymer. We have shown that SP-D and MBL bind to both DNA and RNA effectively and also that SP-D enhances the uptake of DNA by human monocytic cells. Therefore, our results suggest that nucleic acids may be a novel class of ligands for collectins. This class of innate immune proteins could enhance the clearance of DNA that is released by necrotic cells or microbial cells. Our findings may have important biological implications, such as the alleviation of DNA-mediated tissue inflammation.
Palaniyar
Nades
N
MRC Immunochemistry Unit, Department of Biochemistry, Oxford University, Oxford OX1 3QU, UK. Palaniyar.Nadesalingam@bioch.ox.ac.uk
Nadesalingam
Jeya
J
Reid
Kenneth B M
KB
D001665:Binding Sites; D037222:Collectins / Q000276:immunology / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D006801:Humans; D010587:Phagocytosis / Q000502:physiology*; D011485:Protein Binding; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism; D037663:Pulmonary Surfactant-Associated Protein D / Q000378:metabolism; D012313:RNA / Q000378:metabolism*; D020298:U937 Cells
D037222:Collectins; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; D012313:RNA; D004247:DNA