Atherosclerosis is a chronic inflammatory arterial disease characterized by focal accumulation of
lipid and inflammatory cells. It is the number one cause of deaths in the Western world because of its complications of
heart attacks and
strokes.
Statins are effective in only approximately one third of patients, underscoring the urgent need for additional
therapies. B cells that accumulate in atherosclerotic lesions and the aortic adventitia of humans and mice are considered to protect against
atherosclerosis development. Unexpectedly, we found that selective B cell depletion in
apolipoprotein E-deficient (
ApoE(-/-)) mice using a well-characterized mAb to mouse CD20 reduced
atherosclerosis development and progression without affecting the
hyperlipidemia imposed by a high-fat diet. Adoptive transfer of 5 × 10(6) or 5 × 10(7) conventional B2 B cells but not 5 × 10(6) B1 B cells to a lymphocyte-deficient
ApoE(-/-) Rag-2(-/-) common
cytokine receptor γ-chain-deficient mouse that was fed a high-fat diet augmented
atherosclerosis by 72%. Transfer of 5 × 10(6) B2 B cells to an
ApoE(-/-) mouse deficient only in B cells aggravated
atherosclerosis by >300%. Our findings provide compelling evidence for the hitherto unrecognized proatherogenic role of conventional B2 cells. The data indicate that B2 cells can potently promote
atherosclerosis development entirely on their own in the total absence of all other lymphocyte populations. Additionally, these B2 cells can also significantly augment
atherosclerosis development in the presence of T cells and all other lymphocyte populations. Our findings raise the prospect of B cell depletion as a therapeutic approach to inhibit
atherosclerosis development and progression in humans.