tailieunhanh - Báo cáo khoa học: Apolipoproteins A-I and A-II are potentially important effectors of innate immunity in the teleost fish Cyprinus carpio

We have previously shown that high density lipoprotein is the most abundant protein in the carp plasma and dis-plays bactericidal activityin vitro. Therefore the aim of this study was to analyze the contribution of its principal apolipoproteins, apoA-I and apoA-II, in defense. Both apolipoproteins were isolated by a two step procedure involving affinity and gel filtration chromatography and were shown to display bactericidal and/or bacteriostatic activity in the micromolar range against Gram-positive and Gram-negative bacteria, including some fish patho-gens. . | Eur. J. Biochem. 271 2984-2990 2004 FEBS 2004 doi Apolipoproteins A-I and A-II are potentially important effectors of innate immunity in the teleost fish Cyprinus carpio Margarita I. Concha1 Valerie J. Smith2 Karina Castro1 Adriana Bastias1 Alex Romero1 and Rodolfo J. Amthauer1 1Instituto de Bioquimica Facultad de Ciencias Universidad Austral de Chile Valdivia Chile 2Gatty Marine Laboratory School of Biology University of St. Andrews Fife UK We have previously shown that high density lipoprotein is the most abundant protein in the carp plasma and displays bactericidal activity in vitro. Therefore the aim of this study was to analyze the contribution of its principal apolipoproteins apoA-I and apoA-II in defense. Both apolipoproteins were isolated by a two step procedure involving affinity and gel filtration chromatography and were shown to display bactericidal and or bacteriostatic activity in the micromolar range against Gram-positive and Gram-negative bacteria including some fish pathogens. In addition a cationic peptide derived from the C-terminal region of carp apoA-I was synthesized and shown to posses antimicrobial activity EC50 3-6 M against Planococcus citreus. This peptide was also able to potentiate the inhibitory effect of lysozyme in a radial diffusion assay at subinhibitory concentrations of both effectors. Finally limited proteolysis of HDL-associated apoA-I with chymotrypsin in vitro was shown to generate a major truncated fragment which indicates that apoA-I peptides liberated in vivo through a regulated proteolysis could also be involved in innate immunity. Keywords antimicrobial cationic peptide carp HDL innate immunity synergism. The innate immune system is essential to prevent infections during the first critical hours and days of exposure to a pathogen. Although innate immunity is not specific to a particular pathogen in the way that the adaptive immune system is it is of critical relevance in lower vertebrates