OxLDL immune complexes activate complement and induce cytokine production by MonoMac 6 cells and human macrophages

Oxidized low density lipoprotein (OxLDL) is immunogenic and induces autoimmune responses in humans. OxLDL antibodies are predominantly of the proinflammatory IgG1 and IgG3 isotypes. We tested the capacity of immune complexes prepared with copper-oxidized human LDL and affinity chromatography-purified human OxLDL antibodies OxLDL-immune complexes (ICs) to activate complement and to induce cytokine release by MonoMac 6 (MM6) cells and by primary human macrophages. The levels of C4d and C3a were significantly higher in human serum incubated with OxLDL-ICs than after incubation with OxLDL or OxLDL antibody, indicating complement activation by the classical pathway. MM6 cells and primary human macrophages were incubated with OxLDL-ICs, with or without prior conditioning with interferon-γ. After 18 h of incubation, both MM6 cells and primary human macrophages released significantly higher levels of proinflammatory cytokines after incubation with OxLDL-ICs than after incubation with OxLDL or with OxLDL antibody, both in primed and unprimed cells. OxLDL-ICs were more potent activators of MM6 cells than keyhole limpet hemocyanin-ICs. Blocking Fc gamma receptor I (FcγRI) with monomeric IgG1 significantly depressed the response of MM6 cells to OxLDL-ICs. In conclusion, human OxLDL-ICs have proinflammatory properties, as reflected by their capacity to activate the classical pathway of complement and to induce proinflammatory cytokine release from MM6 cells and primary human macrophages. Oxidized low density lipoprotein (OxLDL) is immunogenic and induces autoimmune responses in humans. OxLDL antibodies are predominantly of the proinflammatory IgG1 and IgG3 isotypes. We tested the capacity of immune complexes prepared with copper-oxidized human LDL and affinity chromatography-purified human OxLDL antibodies OxLDL-immune complexes (ICs) to activate complement and to induce cytokine release by MonoMac 6 (MM6) cells and by primary human macrophages. The levels of C4d and C3a were significantly higher in human serum incubated with OxLDL-ICs than after incubation with OxLDL or OxLDL antibody, indicating complement activation by the classical pathway. MM6 cells and primary human macrophages were incubated with OxLDL-ICs, with or without prior conditioning with interferon-γ. After 18 h of incubation, both MM6 cells and primary human macrophages released significantly higher levels of proinflammatory cytokines after incubation with OxLDL-ICs than after incubation with OxLDL or with OxLDL antibody, both in primed and unprimed cells. OxLDL-ICs were more potent activators of MM6 cells than keyhole limpet hemocyanin-ICs. Blocking Fc gamma receptor I (FcγRI) with monomeric IgG1 significantly depressed the response of MM6 cells to OxLDL-ICs. In conclusion, human OxLDL-ICs have proinflammatory properties, as reflected by their capacity to activate the classical pathway of complement and to induce proinflammatory cytokine release from MM6 cells and primary human macrophages. Atherosclerosis is considered the pathologic end point of chronic inflammation of large vessels, triggered by multiple insults and mediated by complex mechanisms, including the activation of immune responses (1Libby P. Inflammation in atherosclerosis..Nature. 2002; 420: 868-874Crossref PubMed Scopus (6916) Google Scholar, 2Lopes-Virella M.F. Virella G. The role of immune and inflammatory processes in the development of macrovascular disease in diabetes..Front. Biosci. 2003; 8 (Suppl.):: 750-768Crossref PubMed Google Scholar). The atheromatous lesions contain modified LDL and corresponding antibodies (3Yla-Herttuala S. Palinski W. Rosenfeld M.E. Parthasarathy S. Carew T.E. Butler S. Witztum J.L. Steinberg D. Evidence for the presence of oxidatively modified low density lipoprotein in atherosclerotic lesions of rabbit and man..J. Clin. Invest. 1989; 84: 1086-1095Crossref PubMed Google Scholar, 4Yla-Herttuala S. Palinski W. Butler S. Picard S. Steinberg D. Witztum J.L. Rabbit and human atherosclerotic lesions contain IgG that recognizes epitopes of oxidized LDL..Arterioscler. Thromb. 1994; 14: 32-40Crossref PubMed Google Scholar), abundant inflammatory cells such as T-helper-lymphocytes, B-lymphocytes, monocytes/macrophages, and foam cells (cholesteryl ester-rich macrophages). We have described in detail the characteristics of purified antibodies reactive with modified LDL (5Mironova M. Virella G. Lopes-Virella M.F. Isolation and characterization of human antioxidized LDL autoantibodies..Arterioscler. Thromb. Vasc. Biol. 1996; 16: 222-229Crossref PubMed Scopus (98) Google Scholar, 6Virella G. Koskinen S. Krings G. Onorato J.M. Thorpe S.R. Lopes-Virella M. Immunochemical characterization of purified human oxidized low-density lipoprotein antibodies..Clin. Immunol. 2000; 95: 135-144Crossref PubMed Scopus (55) Google Scholar, 7Virella G. Thorpe S.R. Alderson N.L. Stephan E.M. Atchley D. Wagner F. Lopes-Virella M.F. DCCT/EDIC Research GroupAutoimmune response to advanced glycosylation end-products of human LDL..J. Lipid Res. 2003; 44: 487-493Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar), the immunogenic modifications of human LDL detected in immune complexes (ICs) isolated from human sera, and the reactivity of IgG fractions isolated from ICs (8Virella G. Thorpe S. Alderson N.L. Derrick M.B. Chassereau C. Rhett J.M. Lopes-Virella M.F. Definition of the immunogenic forms of modified human LDL recognized by human autoantibodies and by rabbit hyperimmune antibodies..J. Lipid Res. 2004; 45: 1859-1867Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar). By all criteria, it is possible to establish that oxidized low density lipoprotein (OxLDL) is immunogenic and that it induces an autoimmune response in humans. Isolated human anti-OxLDL antibodies are predominantly of the IgG isotype, subclasses IgG1 and IgG3 (5Mironova M. Virella G. Lopes-Virella M.F. Isolation and characterization of human antioxidized LDL autoantibodies..Arterioscler. Thromb. Vasc. Biol. 1996; 16: 222-229Crossref PubMed Scopus (98) Google Scholar, 6Virella G. Koskinen S. Krings G. Onorato J.M. Thorpe S.R. Lopes-Virella M. Immunochemical characterization of purified human oxidized low-density lipoprotein antibodies..Clin. Immunol. 2000; 95: 135-144Crossref PubMed Scopus (55) Google Scholar), and react with malondialdehyde-lysine epitopes found in OxLDL (5Mironova M. Virella G. Lopes-Virella M.F. Isolation and characterization of human antioxidized LDL autoantibodies..Arterioscler. Thromb. Vasc. Biol. 1996; 16: 222-229Crossref PubMed Scopus (98) Google Scholar, 6Virella G. Koskinen S. Krings G. Onorato J.M. Thorpe S.R. Lopes-Virella M. Immunochemical characterization of purified human oxidized low-density lipoprotein antibodies..Clin. Immunol. 2000; 95: 135-144Crossref PubMed Scopus (55) Google Scholar) as well as with myeloperoxidase-modified LDL (9Lopes-Virella M.F. Thorpe S.R. Derrick M.B. Chassereau C. Virella G. The immunogenicity of modified lipoproteins..Ann. N. Y. Acad. Sci. 2005; 1043: 367-378Crossref PubMed Scopus (8) Google Scholar). The fact that OxLDL antibodies are largely of the IgG1 and IgG3 subclasses is a strong indicator of their proinflammatory potential (2Lopes-Virella M.F. Virella G. The role of immune and inflammatory processes in the development of macrovascular disease in diabetes..Front. Biosci. 2003; 8 (Suppl.):: 750-768Crossref PubMed Google Scholar). Such antibodies should be able to activate the complement system through the classical pathway and should be able to promote phagocytosis by cells expressing Fcγ receptors (10Virella G. Biosynthesis, metabolism, and biological properties of immunoglobulins.in: Virella G. In Medical Immunology. 5th edition. Marcel Dekker, New York2001: 93-104Crossref Google Scholar). Reports from several groups suggesting that complement activation takes place in the atherosclerotic plaque (11Vlaicu R. Niculescu F. Rus H.G. Cristea A. Immunohistochemical localization of the terminal C5b-9 complement complex in human aortic fibrous plaque..Atherosclerosis. 1985; 57: 163-177Abstract Full Text PDF PubMed Scopus (152) Google Scholar, 12Schmidt R.E. Gessner J.E. Fc receptors and their interaction with complement in autoimmunity..Immunol. Lett. 2005; 100: 56-67Crossref PubMed Scopus (140) Google Scholar) increased our interest in investigating the complement-fixing capacity of OxLDL-ICs, and this became possible as we scaled up our protocol for the isolation of human OxLDL antibodies. The capacity of OxLDL antibodies to promote the ingestion of OxLDL-ICs by phagocytic cells had been demonstrated by experiments showing that OxLDL-ICs engaged Fcγ receptors of human monocyte-derived macrophages and of various macrophage-like cell lines such as THP-1 and U-937, leading to intracellular accumulation of cholesteryl esters and to foam cell transformation (13Atchley D.H. Lopes-Virella M.F. Zheng D. Virella G. Oxidized LDL-anti-oxidized LDL immune complexes and diabetic nephropathy..Diabetologia. 2002; 45: 1562-1571Crossref PubMed Scopus (61) Google Scholar, 14Griffith R.L. Virella G.T. Stevenson H.C. Lopes-Virella M.F. 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G. of a human cell with characteristics of 1988; PubMed Scopus Google Scholar), including cytokine release after In we experiments with primary human macrophages to the of our with MM6 cells. antibodies to OxLDL were purified from of with as in the G. Thorpe S.R. Alderson N.L. Stephan E.M. Atchley D. Wagner F. Lopes-Virella M.F. DCCT/EDIC Research GroupAutoimmune response to advanced glycosylation end-products of human LDL..J. Lipid Res. 2003; 44: 487-493Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar, D.H. Lopes-Virella M.F. Zheng D. Virella G. Oxidized LDL-anti-oxidized LDL immune complexes and diabetic nephropathy..Diabetologia. 2002; 45: 1562-1571Crossref PubMed Scopus (61) Google Scholar). LDL and antibodies to keyhole limpet were from as by the for human of in from in this Oxidized LDL prepared by incubation of isolated human LDL with a of as described M.F. Koskinen S. M. D. R. Chassereau C. C. Virella G. The of copper-oxidized LDL for the of oxidized LDL antibodies by 2000; Full Text Full Text PDF Scopus Google Scholar). The of by a of an of or more that were such have been to react with human OxLDL antibodies M.F. Koskinen S. M. D. R. Chassereau C. C. Virella G. The of copper-oxidized LDL for the of oxidized LDL antibodies by 2000; Full Text Full Text PDF Scopus Google Scholar) and to purified OxLDL antibodies G. Koskinen S. Krings G. Onorato J.M. Thorpe S.R. Lopes-Virella M. Immunochemical characterization of purified human oxidized low-density lipoprotein antibodies..Clin. Immunol. 2000; 95: 135-144Crossref PubMed Scopus (55) Google Scholar). OxLDL antibodies were isolated by a IgG isolated from serum by affinity to the protocol by the After the IgG were by affinity in as (5Mironova M. Virella G. Lopes-Virella M.F. Isolation and characterization of human antioxidized LDL autoantibodies..Arterioscler. Thromb. Vasc. Biol. 1996; 16: 222-229Crossref PubMed Scopus (98) Google Scholar, 6Virella G. Koskinen S. Krings G. Onorato J.M. Thorpe S.R. Lopes-Virella M. Immunochemical characterization of purified human oxidized low-density lipoprotein antibodies..Clin. Immunol. 2000; 95: 135-144Crossref PubMed Scopus (55) Google Scholar). Isolated OxLDL antibodies were through a to and for to In the antibodies were for the is to levels of OxLDL-ICs were prepared as described by Atchley (13Atchley D.H. Lopes-Virella M.F. Zheng D. Virella G. Oxidized LDL-anti-oxidized LDL immune complexes and diabetic nephropathy..Diabetologia. 2002; 45: 1562-1571Crossref PubMed Scopus (61) Google Scholar). In this the of OxLDL and OxLDL for of ICs The were and the of and OxLDL were The of OxLDL found to and of the The of OxLDL-ICs by to cell were prepared with the IgG from human serum by affinity to the protocol by the The of the antibody, by (5Mironova M. Virella G. Lopes-Virella M.F. Isolation and characterization of human antioxidized LDL autoantibodies..Arterioscler. Thromb. Vasc. Biol. 1996; 16: 222-229Crossref PubMed Scopus (98) Google Scholar, M.E. of the affinity in of complexes by Immunol. 1985; PubMed Scopus Google Scholar), A that the for were of the IgG and of The by to the by and were to cell the complement activation of OxLDL-ICs were in of human serum with and incubated for The of OxLDL-ICs to be in experiments by LDL-IC C4d and C3a were by from were and the were and in to a of for the in The data were of human serum human serum with of of human OxLDL antibody, and of human IgG by of purified human IgG for were isolated the described by M. S. D. A. R. for large and of human for and cell Immunol. 2004; PubMed Scopus Google Scholar). the isolated were and in modified with human serum of and incubated in the cells were and a MM6 a human macrophage-like cell A. A. G. of a human cell with characteristics of 1988; PubMed Scopus Google Scholar), were in a in with with serum of by and to from the were a density of and the all and were for the were with cells a density of a The of OxLDL-ICs and were in and unprimed a of to h the cells with OxLDL-ICs. The of human OxLDL-ICs in experiments to be after from to is of the of in of as in with The LDL-IC in were by the of and after of as described (8Virella G. Thorpe S. Alderson N.L. Derrick M.B. Chassereau C. Rhett J.M. Lopes-Virella M.F. Definition of the immunogenic forms of modified human LDL recognized by human autoantibodies and by rabbit hyperimmune antibodies..J. Lipid Res. 2004; 45: 1859-1867Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar). cells were incubated in with OxLDL and human OxLDL were with After incubation, the cell were and cytokine the of and were by with up to antibodies The is to the and to for from all cytokine the of and the or for the activation of MM6 cells by OxLDL-ICs, we incubated primed MM6 cells with IgG1 and for to and with of the The were of and and the cells were incubated for the end of this OxLDL-ICs were to the MM6 cells. point in In in the The of the were The to to multiple of the in cytokine levels with the transformation of the data and the to are as in the of C4d significantly higher in serum incubated with and OxLDL-ICs than that in serum incubated in The of C4d in serum incubated with OxLDL or anti-OxLDL and in to the corresponding in OxLDL-ICs, were significantly from in the serum The of OxLDL-ICs are in The of C3a were higher serum incubated with or OxLDL-ICs than in serum The of C3a in serum incubated with OxLDL or anti-OxLDL were significantly from in serum of the complement system activation by oxidized low density lipoprotein immune complexes The levels of C4d and C3a were in serum incubated with OxLDL-ICs human OxLDL and human oxidized LDL as well as in a of the serum and OxLDL antibodies and corresponding OxLDL-ICs were in this The data are as for complement of by a to the the levels in serum incubated with OxLDL-ICs and in serum by the The activation of MM6 cells by cytokine levels in the We cytokines to be released by activated macrophages and MM6 with proinflammatory properties, we is considered an and the IgG of the anti-OxLDL to the were as unprimed MM6 a release of cytokines and with OxLDL or OxLDL to the in to in OxLDL-ICs The in the MM6 cells primed by with for h OxLDL-ICs or to the cells In in the release of significantly higher levels of cytokines by MM6 cells incubated with OxLDL-ICs, with the of and of cytokine the of MM6 cells. MM6 cells were primed by incubation with for After the cells were incubated for 18 h with OxLDL OxLDL-ICs or human OxLDL antibodies were in this After incubation, the and cytokine levels were The data are as for in of by after transformation of the data a to the the levels in serum incubated with OxLDL-ICs and in serum the of the cytokine levels in primed and unprimed MM6 cells incubated with OxLDL-ICs for antibodies were in this The data are as for in were the the of we experiments with primed MM6 cells of OxLDL-ICs with OxLDL antibodies isolated from The data in this of experiments were to our of OxLDL-ICs release of and with of OxLDL or OxLDL were In unprimed the levels in the of MM6 cells incubated with OxLDL-ICs were significantly higher than in the of MM6 cells incubated with OxLDL or OxLDL The in primed cells. The levels released by MM6 cells incubated with OxLDL-ICs were significantly higher than in the of MM6 cells incubated with OxLDL or OxLDL The of OxLDL-ICs in human monocyte-derived macrophages tested to described for the experiments with MM6 cells. In unprimed human monocyte-derived OxLDL-ICs a release of cytokines and with OxLDL or OxLDL The in the macrophages primed by with for h or to the cells. the cells the release of cytokines by macrophages incubated with OxLDL-ICs. The cytokine levels in primed macrophages to OxLDL-ICs were significantly higher than in the of macrophages incubated with OxLDL antibody, or 6 MM6 cells with a low of OxLDL-ICs after with human IgG1 to and a to The levels of were in the as the end point for MM6 IgG1 of and significantly release by MM6 cells with OxLDL-ICs by and In human for the of OxLDL-ICs. the in the levels of proinflammatory cytokines in both MM6 and human monocyte-derived incubated with OxLDL-ICs is in with in human monocyte-derived in unprimed and MM6 cells OxLDL is able to cytokine release were the presence of IgG in the the of by of human OxLDL with LDL in the and with the of serum of in the the activation of MM6 cells. be for our we levels in our and detected levels of the However, the of MM6 cells to Y. of the in system proinflammatory cytokine release from human with a human system and with the rabbit Immunol. 2002; Google Scholar), we the of a higher of in this is a than OxLDL of the response of MM6 cells to and to human OxLDL of detected in OxLDL were OxLDL to to the of OxLDL in of OxLDL-ICs. as a The cytokine levels after incubation with OxLDL and OxLDL-ICs were of the in experiments 6 to the cytokine levels in MM6 with OxLDL by the to the cytokine levels in MM6 with OxLDL by the to the cytokine levels in MM6 with OxLDL by the to the cytokine levels in MM6 with OxLDL by the 18 to the cytokine levels in MM6 with OxLDL by the to the cytokine levels in MM6 with OxLDL by the immune MonoMac oxidized low density of detected in OxLDL were to to the of OxLDL in of as a The cytokine levels after incubation with OxLDL and OxLDL-ICs were of the in experiments to the cytokine levels in MM6 with OxLDL by the in a immune MonoMac oxidized low density The experiments with human monocyte-derived macrophages to unprimed cells incubated in and cells incubated with OxLDL The levels of were the significantly higher in human monocyte-derived macrophages incubated in the presence of OxLDL than in primed human primary macrophages incubated in A that we the of OxLDL-ICs with ICs prepared with a with to that of to their as MM6 cell that be to this we prepared with human in both of ICs activate MM6 OxLDL-ICs are more potent of cytokine The of the proinflammatory in is for the development of and is a the involvement of in the of (2Lopes-Virella M.F. 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Lopes-Virella M.F. and Immunol. 2003; PubMed Scopus Google Scholar), and for it is to be a leading to by that OxLDL antibodies are predominantly of subclasses and (5Mironova M. Virella G. Lopes-Virella M.F. Isolation and characterization of human antioxidized LDL autoantibodies..Arterioscler. Thromb. Vasc. Biol. 1996; 16: 222-229Crossref PubMed Scopus (98) Google Scholar, 6Virella G. Koskinen S. Krings G. Onorato J.M. Thorpe S.R. Lopes-Virella M. Immunochemical characterization of purified human oxidized low-density lipoprotein antibodies..Clin. Immunol. 2000; 95: 135-144Crossref PubMed Scopus (55) Google Scholar, G. Thorpe S. Alderson N.L. Derrick M.B. Chassereau C. Rhett J.M. Lopes-Virella M.F. Definition of the immunogenic forms of modified human LDL recognized by human autoantibodies and by rabbit hyperimmune antibodies..J. Lipid Res. 2004; 45: 1859-1867Abstract Full Text Full Text PDF PubMed Scopus (50) Google Scholar), the of our complement activation experiments that the classical pathway should be activated by OxLDL-ICs. this we incubated human OxLDL-ICs with human serum and the levels of C3a and is complement is by of the is the classical pathway is activated The complement Virella G. In Medical Immunology. Marcel Dekker, New York2001: Google Scholar). our of increased levels of both C3a and C4d that OxLDL-ICs activate the complement system through the classical pathway. is we that complement and in atherosclerotic lesions R. of complement activation in 2003; 14: PubMed Scopus Google Scholar). OxLDL-ICs are to be a leading to complement activation in the atheromatous the is such as C3a and be and to the of the inflammatory through their properties and by the of cell cells R. of complement activation in 2003; 14: PubMed Scopus Google Scholar). The of terminal complement been in the atheromatous and is suggesting that are proinflammatory through the activation of leading to the release of and and the of cells R. of complement activation in 2003; 14: PubMed Scopus Google Scholar, F. Rus The role of complement activation in Res. 2004; PubMed Google Scholar). with the of OxLDL antibodies the of the activation of MM6 cells and human monocyte-derived macrophages by OxLDL-ICs prepared with human OxLDL and human as reflected by the release of of proinflammatory including and of have been demonstrated in atheromatous in the and of the inflammatory (2Lopes-Virella M.F. Virella G. The role of immune and inflammatory processes in the development of macrovascular disease in diabetes..Front. Biosci. 2003; 8 (Suppl.):: 750-768Crossref PubMed Google Scholar). The release of cytokines by MM6 cells and human monocyte-derived macrophages after with is and macrophages are the predominant cell in atheromatous of cells from human aortic atherosclerotic PubMed Scopus Google Scholar, a in Res. 2005; PubMed Scopus Google Scholar). activated the release predominantly a cytokine that is to a role in the development of a in Res. 2005; PubMed Scopus Google Scholar). that and in the atheromatous plaque to the inflammatory The release of by MM6 cells this by the of inflammatory it in the experiments with human monocyte-derived is from our had that the primary receptor in the interaction of with human macrophages and macrophage-like cell lines M.F. Binzafar N. Rackley S. Takei A. La Via M. Virella G. The uptake of LDL-IC by human macrophages: predominant involvement of the Fc gamma RI receptor..Atherosclerosis. 1997; 135: 161-170Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar). However, in that we rabbit antibodies and human it to that the be for MM6 cell activation human OxLDL-ICs. that is the primary Fcγ receptor the of MM6 activation with IgG1 the the that receptors be in MM6 cell such as an that be the of We that OxLDL the release of low levels of cytokines in unprimed levels that were significantly increased in primed MM6 cells In primed unprimed human monocyte-derived macrophages to OxLDL in the that MM6 cells a in of macrophages incubated with OxLDL to incubated with that the of MM6 cells the of to monomeric OxLDL or of that or after of the such as the of by OxLDL antibodies and LDL or of the with were in our is the fact that in our experiments OxLDL-ICs to be more potent than is for groups have the of ICs R. immune complexes induce of human Thromb. Vasc. Biol. PubMed Scopus Google Scholar). The is that the fact that is a the immune response to is to the of antibodies in our had a of with an of for our purified OxLDL G. Lopes-Virella M.F. and Immunol. 2003; PubMed Scopus Google Scholar). of higher affinity should be more in leading to the of ICs that are more and than with in be more MM6 cell activators than OxLDL-ICs, than the The higher of OxLDL-ICs as MM6 cell activators that the in the of an a role in cell In conclusion, data by and by in of the of OxLDL-ICs inflammatory as well as a of in human that ICs by modified LDL and corresponding antibodies a role in (2Lopes-Virella M.F. Virella G. The role of immune and inflammatory processes in the development of macrovascular disease in diabetes..Front. Biosci. 2003; 8 (Suppl.):: 750-768Crossref PubMed Google Scholar). LDL (3Yla-Herttuala S. Palinski W. Rosenfeld M.E. Parthasarathy S. Carew T.E. Butler S. Witztum J.L. Steinberg D. Evidence for the presence of oxidatively modified low density lipoprotein in atherosclerotic lesions of rabbit and man..J. Clin. Invest. 1989; 84: 1086-1095Crossref PubMed Google Scholar, Y. A oxidized lipoprotein recognizes foam cells in atherosclerotic of oxidized and Biol. 1994; Full Text PDF PubMed Google Scholar, N. Y. Y. S. R. S. Immunohistochemical localization of epitopes of advanced end in human atherosclerotic Full Text Full Text PDF PubMed Scopus (76) Google Scholar), the corresponding antibodies S. Palinski W. Butler S. Picard S. Steinberg D. Witztum J.L. Rabbit and human atherosclerotic lesions contain IgG that recognizes epitopes of oxidized LDL..Arterioscler. Thromb. 1994; 14: 32-40Crossref PubMed Google Scholar), and complement have been demonstrated in atheromatous have demonstrated a the levels of modified and the development of diabetic (13Atchley D.H. Lopes-Virella M.F. Zheng D. Virella G. Oxidized LDL-anti-oxidized LDL immune complexes and diabetic nephropathy..Diabetologia. 2002; 45: 1562-1571Crossref PubMed Scopus (61) Google Scholar, Virella G. M. Lopes-Virella M. of in with A from the of PubMed Scopus Google Scholar), disease M.F. Virella G. Koskinen S. to oxidized LDL and immune complexes as for disease in Immunol. PubMed Scopus Google Scholar, Virella G. Lopes-Virella M.F. to oxidized LDL disease in a from the of PubMed Scopus Google Scholar), and increased M.F. M.B. S. Virella G. the DCCT/EDIC Research complexes modified are to the of in with Scholar). is a of a role for the autoimmune response to modified in humans. by a by the of and as well as by the Research of the of Medical and by from the Research The and of and through from the of and of the of and and of