APOE and atherosclerosis: In CTLA-4-transgenic/Apoe-/- mice, overexpression of CTLA-4 can significantly reduce the formation of atherosclerotic lesions and significantly inhibit the accumulation of macrophages and CD4+T cells in the plaque, and then regulate atherosclerosis by down-regulating the expression of costimulatory molecules CD80, CD86, and CD28 (25).