Antibodies against electronegative LDL inhibit atherosclerosis in LDLr-/- mice

Abstract

In order to determine the effect of antibodies against electronegative low-density lipoprotein LDL(-) on atherogenesis, five groups of LDL low receptor-deficient (LDLr-/-) mice (6 per group) were immunized with the following antibodies (100 µg each): mouse anti-LDL(-) monoclonal IgG2b, rabbit anti-LDL(-) polyclonal IgG or its Fab fragments and mouse irrelevant monoclonal IgG and non-immunized controls. Antibodies were administered intravenously one week before starting the hypercholesterolemic diet (1.25% cholesterol) and then every week for 21 days. The passive immunization with anti-LDL(-) monoclonal IgG2b, polyclonal antibody and its derived Fab significantly reduced the cross-sectional area of atherosclerotic lesions at the aortic root of LDLr-/-mice (28.8 ± 9.7, 67.3 ± 17.02, 56.9 ± 8.02 µm 2 (mean ± SD), respectively) compared to control (124.9 ± 13.2 µm 2 ). Vascular cell adhesion molecule-1 protein expression, quantified by the KS300 image-analyzing software, on endothelium and the number of macrophages in the intima was also decreased in aortas of mice treated with anti-LDL(-) monoclonal antibody (3.5 ± 0.70 per field x 10) compared to controls (21.5 ± 3.5 per field x 10). Furthermore, immunization with the monoclonal antibody decreased the concentration of LDL(-) in blood plasma (immunized: 1.0 ± 1.4; control: 20.5 ± 3.5 RLU), the amount of cholesterol oxides in plasma (immunized: 4.7 ± 2.7; control: 15.0 ± 2.0 pg COx/mg cholesterol) and liver (immunized: 2.3 ± 1.5; control: 30.0 ± 26.0 pg COx/mg cholesterol), and the hepatic content of lipid hydroperoxides (immunized: 0.30 ± 0.020; control: 0.38 ± 0.15 ng/mg protein). In conclusion, antibodies against electronegative LDL administered intravenously may play a protective role in atherosclerosis.

Is Plasma Alpha-Tocopherol Associated with Electronegative LDL in Obese Adolescents?

“…Regarding that, as the evaluation of oxidative stress in adolescents is sparsely described in the literature, this possibility needs more investigation. Grosso et al (37) evaluated the immune response to LDL(2) in mice and observed a similar profile. According to these authors, low bioavailability of antibodies to LDL(2) is correlated to generation of high immune-complex to LDL(2).…”

Cloning and expression of an anti-LDL(-) single-chain variable fragment, and its inhibitory effect on experimental atherosclerosis

“…18 We previously reported that passive immunization using an anti-LDL(-) mAb in Ldlr −/− mice decreased both the cross-sectional area and the number of foam cells in atherosclerotic lesions. 19 In this study, we cloned and expressed an anti-LDL(-) 2C7 scFv in P. pastoris and determined its anti-atherogenic activity on 264.7 RAW macrophages and in LDL receptor gene knockout mice (Ldlr −/− ). Our findings reinforce the potential of novel antibody-based immunotherapeutic approaches that can lead to therapies for complex diseases such as atherosclerosis.…”

“…The experiments were performed using an initial atherosclerotic lesion protocol as previously described. 19 All mice were fed a semisynthetic chow that was based on a Western-type diet containing 20% fat, 0.5% (w/w) cholesterol (Sigma-Aldrich), 0.5% (w/w) colic acid (Sigma-Aldrich), 16.5% casein, vitamins and minerals according to the recommendations of American Institute of Nutrition (AIN)-93. 52 All procedures were approved by the Ethics Committee for Animal Studies of the Faculty of Pharmaceutical Sciences, University of Sao Paulo in agreement with the guidelines of the Brazilian College for Animal Experimentation.…”

New Alternatives for Atherosclerosis Treatment Based on Immunomodulation

“…Grosso et al have reported that the passive immunization with xenogeneic polyclonal antibodies, xenogeneic Fab fragments, and allogeneic monoclonal IgG antibodies, reactive to electronegative LDL (minimally modified LDL), significantly reduced atherosclerosis in LDL-receptor-deficient mice [10].…”

“…Additional immunotherapeutic approaches have been recently evaluated with promising results [9][10][11][12][13][14][15].…”