Recombinant Human Antibodies Against Aldehyde-Modified Apolipoprotein B-100 Peptide Sequences Inhibit Atherosclerosis

Abstract

Background-Accumulation and oxidation of LDL are believed to be important initiating factors in atherosclerosis.Oxidized LDL is recognized by the immune system, and animal studies have suggested that these immune responses have a protective effect against atherosclerosis. Aldehyde-modified peptide sequences in apolipoprotein B-100 (apoB-100) are major targets for these immune responses. Methods and Results-Human IgG1 antibodies against 2 malondialdehyde (MDA)-modified apoB-100 peptide sequences were produced through screening of a single-chain antibody-fragment library and subsequent cloning into a pcDNA3 vector. Three weekly doses of these antibodies were injected into male apoE Ϫ/Ϫ mice. Phosphate-buffered saline and human IgG1 antibodies against fluorescein isothiocyanate were used as controls. One of the IgG1 antibodies significantly and dose-dependently reduced the extent of atherosclerosis as well as the plaque content of oxidized LDL epitopes and macrophages. In cell culture studies, human monocytes were incubated with native LDL or oxidized LDL, in the presence of antibodies. The same antibody induced an increase in monocyte binding and uptake of oxidized LDL. Conclusions-These findings suggest that antibodies are important mediators of atheroprotective immune responses directed to oxidized LDL. Thus, passive immunization against MDA-modified apoB-100 peptide sequences may represent a novel therapeutic approach for prevention and treatment of cardiovascular disease.

Autoantibody against the amino acid sequence 661–680 in apo B-100 is associated with decreased carotid stenosis and cardiovascular events

“…These results are in good agreement with our previous experimental studies demonstrating that immunization of apo E KO mice with MDA-p45 peptide results in an increase in specific IgG associated with a decrease in aortic plaque area and plaque content of inflammatory cells [15] . Moreover, treatment of apo E KO mice with human recombinant IgG specific for the MDA-p45 sequences also reduced aortic plaque area and decreased plaque inflammation [17]. Taken together these observations support the notion that the p45 sequence of apo B-100 (amino acids 661-680) is a potential target for immunomodulatory treatment of atherosclerosis.…”

“…Immunization of apo E knockout (KO) mice with some of these native and aldehyde-modified apo B-100 peptide sequences induces an immunoglobulin switch from IgM to IgG that is accompanied by an inhibition of atherosclerosis [14][15][16]. To study the possible atheroprotective effects of this IgG we produced recombinant human IgG1 specific for a malondialdehyde (MDA)-modified peptide corresponding to the sequence between amino acids 661 and 680 in apo B-100 (p45) [17]. Subcutaneous immunization with MDA-p45 peptide has previously been shown to inhibit atherosclerosis by about 50% in apo E KO mice [15].…”

Low levels of IgG autoantibodies against the apolipoprotein B antigen p210 increases the risk of cardiovascular death after carotid endarterectomy

“…26 A human recombinant IgG specific for the MDA-modified apo B peptide p45 inhibits the development of atherosclerosis in hypercholesterolemic mice and induces regression of lesions when combined with cholesterol lowering. 27,28 Studies performed on cultured cells have shown that immune complexes of this antibody and oxidized LDL inhibit cytokine release from monocytes through interaction with the inhibitory FcγIIb receptor. 29 Treatment of obese, hypercholesterolemic non-human primates with this antibody resulted in lower plasma levels of pro-inflammatory cytokines.…”

Antigen-Driven Evolution of B Lymphocytes in Coronary Atherosclerotic Plaques

“…However, other data indicated that activation of an adaptive immune response to self Ags like heat shock protein 60 and ␤ 2 glycoprotein may be proatherogenic, whereas the adaptive immune response to oxidized LDL might be both proatherogenic or atheroprotective (2,(43)(44)(45)(46). Passive immunization, using a mAb to epitopes identified in apolipoprotein B100, has also been shown to reduce atherosclerosis in hyperlipidmic mice (47). However, before clinical testing of a vaccination strategy based on apolipoprotein B100 several questions related to the pathogenic role of adaptive immune response need to be addressed.…”