Transfer of CD4(+) T cells aggravates atherosclerosis in immunodeficient apolipoprotein E knockout mice.

BACKGROUND Atherosclerosis is associated with immune responses to oxidized lipoproteins and certain microorganisms, but the role of specific immunity has remained unclear. METHODS AND RESULTS To study the role of immunity in atherosclerosis, we crossed atherosclerosis-prone apoE(-/-) mice with immunodeficient scid/scid mice. The offspring showed a 73% reduction in aortic fatty streak lesions when compared with immunocompetent apoE(-/-) mice. Transfer of CD4(+) T cells from apoE(-/-) to immunodeficient apoE(-/-)/scid/scid mice increased lesions by 164%. This was associated with the infiltration of transferred T cells into lesions, increased circulating interferon-gamma levels, and increased I-A expression in lesions. CONCLUSIONS CD4(+) T cells carry disease-promoting immunity in atherosclerosis.