Mouse cytomegalovirus antigenic immune stimulation is sufficient to aggravate atherosclerosis in hypercholesterolemic mice

We have previously demonstrated that mouse cytomegalovirus (MCMV) infection aggravates atherosclerosis by stimulating the ongoing inflammatory process in the vascular wall. Here we investigated whether MCMV antigenic immune stimulation by UV-MCMV injection is sufficient to aggravate atherosclerosis. In addition we analyzed whether low viral doses are sufficient to stimulate atherosclerosis. Therefore, apoE−/− mice received a low dose injection with infectious virus (MCMV) or replication-deficient virus (UV-inactivated MCMV, UV-MCMV). Atherosclerosis progression, influx of inflammatory cells in atherosclerotic lesions and internal organs and the number of MCMV DNA copies in various organs were determined at 2 weeks after injection. After injection with infectious virus, MCMV DNA was present in internal organs, while no MCMV DNA could be detected after UV-MCMV injection. Interestingly, both MCMV and UV-MCMV significantly increased mean atherosclerotic lesion area and T cell number in the atherosclerotic lesions, while only MCMV infection increased T cell numbers in the internal organs. These data indicate that in apoE−/− mice both low dose infectious MCMV as well as MCMV antigenic injections are sufficient for atherosclerosis aggravation.