Open AccessApolipoproteins A‐I and A‐II are potentially important effectors of innate immunity in the teleost fish Cyprinus carpio
Author(s) -
Concha Margarita I.,
Smith Valerie J.,
Castro Karina,
Bastías Adriana,
Romero Alex,
Amthauer Rodolfo J.
Publication year - 2004
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.2004.04228.x
Subject(s) - innate immune system , proteolysis , biology , lysozyme , carp , microbiology and biotechnology , peptide , effector , in vivo , cyprinus , biochemistry , chemistry , fish <actinopterygii> , enzyme , receptor , fishery
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 (EC 50 = 3–6 µ 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.