Publication Description
Gabriel Virella 1 ,* ,
Suzanne R. Thorpe ,
Nathan L. Alderson ,
Elias M. Stephan ,
Daniel Atchley * , ,
Francesco Wagner * , and
Maria F. Lopes-Virella and the DCCT/EDIC Research Group 2
* Department of Microbiology and Immunology, Medical University of South Carolina, Charleston, SC 92425
Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208
Department of Medicine, Division of Endocrinology-Metabolism-Nutrition, Medical University of South Carolina, and Ralph H. Johnson VAMC, Charleston, SC 92425
1 To whom correspondence should be addressed. e-mail: virellag{at}musc.edu
Advanced glycosylation end-products (AGEs) are believed to play a significant role in the development of vascular complications in diabetic patients. One such product, AGE-LDL, has been shown to be immunogenic. In this report, we describe the isolation and characterization of human AGE-LDL antibodies from the sera of seven patients with Type 1 diabetes by affinity chomatography using an immobilized AGE-LDL preparation that contained primarily the AGE N (carboxymethyl)lysine (CML, 14.6 mmol/mol lysine), and smaller amounts of N (carboxyethyl)lysine (CEL, 2.7 mmol/mol lysine). The isolated antibodies were predominantly IgG of subclasses 1 and 3, and considered proinflammatory because of their ability to promote Fc R-mediated phagocytosis and to activate complement. We determined dissociation constants ( K d ) for the purified antibodies. The average K d values (4.76 ± 2.52 x 10 -9 mol/l) indicated that AGE-LDL antibodies are of higher avidity than oxidized LDL antibodies measured previously ( K d = 1.53 ± 07 x 10 -8 ml/l), but of lower avidity than rabbit polyclonal LDL antibodies ( K d = 9.34 x 10 -11 ). Analysis of the apolipoprotein B-rich lipoproteins isolated with polyethylene glycol-precipitated antigen-antibody complexes from the same patients showed the presence of both CML and CEL, thus confirming that these two modifications are recognized by human autoantibodies.
A comparative study of the reactivity of purified AGE-LDL antibodies with CML-LDL and CML-serum albumin showed no cross-reactivity.
Abbreviations: AGE, advanced glycosylation end-product; ALE, advanced lipoxidation end-product; CEL, (carboxyethyl)lysine; CML, (carboxymethyl)lysine; EDIC, Epidemiology of Diabetes Complication; EIA, enzymoimmunoassay; IC, immune complexes; oxLDL, oxidized LDL Supplementary key words modified lipoproteins diabetes immunogenicity of advanced glycosylation end-products-LDL advanced glycosylation end-products-LDL antibodies
CiteULike Complore Connotea Del.icio.us Digg Reddit Technorati What's this?