Characterization of anti-advanced glycation end product antibodies to nonenzymatically lysine-derived and arginine-derived glycated products

Abstract

N(epsilon)-(carboxymethyl)lysine (CML) and N(epsilon)-(carboxyethyl)lysine (CEL) termed advanced glycation end products (AGEs) are known to be produced by nonenzymatic glycation between bovine serum albumin (BSA) and D-glucose. This study is to characterize the immunoreactivity of anti-AGE antibodies including anti-CML and anti-CEL antibodies. Using AGE-modified BSA (AGE-BSA) as an immunogen, a polyclonal anti-AGE immunoglobulin G (IgG) was produced. The anti-AGE IgG could strongly detect AGEs formed on BSA, at least in part, AGEs produced on both residues Lys and Arg due to its immunoreaction with Lys-derived and Arg-derived AGEs produced by NaCNBH(3), a reducing agent, in amino acid glycation analysis, but the pre-immune serum could not. As the anti-CML antibody could also strongly react with AGE-BSA, this suggests that CML is a major nonenzymatically glycated product cross-linked to BSA. Furthermore, CEL is associated with distinguishable polymerization of BSA from CML polymerization of BSA, though weaker than CML and was not produced by Lys glycation analysis. These results indicate that the anti-AGE antibody is effective for detecting both Lys-derived and Arg-derived AGEs, and CML and CEL distinctively polymerize albumin as major AGEs present on AGE-BSA.