Recombinant antibodies to an oxidized low-density lipoprotein epitope induce rapid regression of atherosclerosis in Apobec-1-/-/low-density lipoprotein receptor-/- mice

Objectives The present study tested the hypothesis that treatment with human recombinant immunoglobulin G1 (IgG1) antibodies against a specific oxidized low-density lipoprotein (oxLDL) epitope will induce regression of existing atherosclerotic lesions in LDL receptor-deficient mice expressing apolipoproteln B-100 (apoB-100) (Apobec-1(-/-)/ LDLR-/-). Background Oxidized LDL plays an essential role in the pathogenesis of atherosclerosis. We previously showed that an antibody against oxLDL reduces progression of atherosclerosis in mice. Methods Apobec-1(-/-)/LDLR-/- mice were fed a high-fat diet until they were 24 weeks and were subsequently transferred to chow. Starting at 25 weeks, mice were given 3 weekly injections of either of 2 recombinant human IgG1 antibodies (IEI-E3 or 2DO3) against a malondialdehyde-modified apoB-100 peptide sequence. Results At 25 weeks, atherosclerotic lesions covered 10.3 +/- 3.7% of the descending aorta. Transfer to chow diet resulted in a modest regression of atherosclerosis over a 5-week period (8.28 +/- 4.36%; p = NS). Antibody treatment induced additional regression of atherosclerosis by 50% (2DO3; p = 0.001) and 36% (IEI-E3; p = 0.004) compared with control IgG1. The 2DO3 treatment also reduced plaque inflammation, enhanced plaque expression of the adenosine triphosphate-binding cassette transporter A1, and inhibited expression of monocyte chemoattractant protein-1 in cultured monocytes. Conclusions Human IgG1 against a specific oxLDL epitope can induce rapid and substantial regression of atherosclerotic lesions, possibly by stimulating lipid efflux and inhibiting macrophage recruitment. These recombinant human antibodies could represent a novel strategy for rapid regression/stabilization of atherosclerotic lesions.