To examine how immunomodulation by agonistic or antagonistic CD137 treatment affects vein graft atherosclerosis, mice were treated with either agonistic CD137 antibodies that induce T-cell activation (agonistic treatment, aCD137) or CD137L blocking antibodies to reduce T-cell activation (antagonistic treatment, aCD137L) (Figure 3A). This evidence concerns the gene TNFRSF9 and atherosclerosis.