Nature Medicine
9, 736 - 743 (2003)
Published online: 12 May 2003; | doi:10.1038/nm876
Pneumococcal vaccination decreases atherosclerotic lesion formation: molecular mimicry between Streptococcus pneumoniae and oxidized LDLChristoph J Binder1, 4, Sohvi Hörkkö1, 3, 4, Asheesh Dewan1, 4, Mi-Kyung Chang1, Emily P Kieu1, Carl S Goodyear2, Peter X Shaw1, Wulf Palinski1, Joseph L Witztum1
& Gregg J Silverman21
Divisions of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0682 USA. 2
Rheumatology, Allergy & Immunology, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0682 USA. 3
Department of Internal Medicine and Biocenter Oulu, Kajaanintie 50, University of Oulu, 90220 Oulu, Finland. 4
These authors contributed equally to this work.
Correspondence should be addressed to Joseph L Witztum jwitztum@ucsd.eduDuring the progression of atherosclerosis, autoantibodies are induced to epitopes of oxidized low-density lipoprotein (oxLDL) and active immunization of hypercholesterolemic mice with oxLDL ameliorates atherogenesis. We unexpectedly found that many autoantibodies to oxLDL derived from 'naive' atherosclerotic mice share complete genetic and structural identity with antibodies from the classic anti-phosphorylcholine B-cell clone, T15, which protect against common infectious pathogens, including pneumococci. To investigate whether in vivo exposure to pneumococci can affect atherogenesis, we immunized Ldlr-/- mice with Streptococcus pneumoniae. This induced high circulating levels of oxLDL-specific IgM and a persistent expansion of oxLDL-specific T15 IgM-secreting B cells primarily in the spleen, which were cross-reactive with pneumococcal determinants. Pneumococcal immunization decreased the extent of atherosclerosis, and plasma from these mice had an enhanced capacity to block the binding of oxLDL to macrophages. These studies show molecular mimicry between epitopes of oxLDL and S. pneumoniae and indicate that these immune responses can have beneficial effects.
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