Immunization with a combination of ApoB and HSP60 epitopes significantly reduces early atherosclerotic lesion in Apob tm2SgyLdlr tm1Her/J mice

Abstract

Objective HSP60 is emerging as an immunodominant target of autoantibodies in atherosclerosis and recent studies have revealed oxLDL as a key antigen in the development of atherosclerosis. In this study, we assay whether immunizing Apob tm2SgyLdlr tm1Her/J mice with a combination of ApoB and human HSP60 peptides has an additive effect on atheroprotection compared to ApoB or HSP60 peptides applied alone by following atherosclerotic lesion development. Methods and results In this study, 2 weeks after the first immunization, Apob tm2SgyLdlr tm1Her/J mice were placed on a high-fat diet for 8 weeks followed by 2 weeks on a normal diet allowing the mice to adapt to the environment before sacrifice. High levels of ApoB and HSP60 antibodies were detectable in week 2 and week 12 following the first immunization with KLH-conjugated ApoB and HSP60 peptides either individually or in combination. Histological analyses demonstrated that mice immunized with both, ApoB and HSP60 peptides, showed the most significant reduction in atherosclerotic lesions (41.3%; p < 0.001) compared to a reduction of 14.7% ( p < 0.05) and 21.1% ( p < 0.01) in mice immunized with ApoB or HSP60 peptides, respectively; control mice were immunized with either PBS or adjuvant alone. These results were further supported by significant differences in the cellular and humoral immune responses between test animals. Conclusions Immunization with a combination of ApoB and HSP60 peptide antigens significantly reduced early atherosclerotic lesions in the Apob tm2SgyLdlr tm1Her/J mouse model of atherosclerosis. This approach offers promise as a novel strategy for developing anti-atherosclerotic agents.