Characterization of human monoclonal autoantibody Fab fragments against oxidized LDL.
Oxidized low-density lipoprotein (oxLDL) is a key autoantigen in atherosclerosis. The genetic structures and pathogenic roles of autoantibodies against this protein remain to be established. In this study, we cloned several monoclonal IgG autoantibody Fab fragments specific for oxLDL from peripheral blood lymphocytes of atherosclerosis patients, using phage display technology. The sequences of their variable regions were determined at the cDNA level. The closest germline counterparts for the heavy chains belonged to the V(H)3 or V(H)1 family. The sequences and lengths of complementarity-determining regions (CDR)3-V(H) were diverse, and frequent mutations of positively charged amino acids (particularly arginine) over entire V(H) and V(L) sequences were observed. It is proposed that anti-oxLDL autoantibody formation is driven by antigens. Among the Fabs, P2-8 and P3-175 bound to both MDA-LDL and Cu-oxLDL, and inhibited the uptake of oxLDL by macrophages, suggesting the epitope(s) recognized by the Fabs is a part of ligands on oxLDL that is involved in uptake by macrophage scavenger receptor. These human autoantibody Fabs require detailed investigation to ascertain their potential as agents for clinical applications.
Jeon
Young-Eun
YE
Laboratory of Immunology, Institute for Medical Science, Ajou University School of Medicine, Suwon 443-721, South Korea.
Seo
Chang-Won
CW
Yu
Eun Sun
ES
Lee
Cheol Joo
CJ
Park
Sae-Gwang
SG
Jang
Young-Ju
YJ
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000276:immunology*; D050197:Atherosclerosis / Q000276:immunology*; D001323:Autoantibodies / Q000235:genetics / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology*; D007074:Immunoglobulin G / Q000235:genetics / Q000276:immunology*; D008077:Lipoproteins, LDL / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000276:immunology; D008315:Malondialdehyde / Q000031:analogs & derivatives / Q000276:immunology; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001324:Autoantigens; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D008315:Malondialdehyde