Accelerated atherosclerosis in hyperlipidemic C57BL/6 mice treated with cyclosporin A.

We and others have demonstrated that T lymphocytes are prominent components of atherosclerotic lesions. We hypothesized that if T cells were necessary for the development of atherosclerosis it would be possible to demonstrate its prevention or retardation in T-cell-suppressed mice. To test this hypothesis, CyA, a potent suppressor of T-cell activation, was used to treat C57BL/6 mice undergoing lipid hyperalimentation. Mice receiving normal mouse chow were completely free of atherosclerotic lesions. In mice receiving the atherogenic diet plus control oil injections, lesions of the aorta and coronary arteries were observed at 135 days and increased progressively in area until 310 days. Somewhat surprisingly, mice given the atherogenic diet plus CyA injections displayed even larger lesions at all three observed time intervals. Although CyA did suppress T-cell reactivity sufficiently to obtain the expected prolongation of skin allografts, it did not suppress the development or progression of atherosclerotic lesions.