The elevated activation of CD4+ and CD8+ T cells, along with the secretion of pro-atherogenic cytokines like IL-2, IFN-γ, and TNF-α, exacerbates atherosclerosis in mice lacking the low-density lipoprotein receptor (Ldlr knockout mice) and receiving KLF2-deficient DCs. The gene discussed is CD4; the disease is atherosclerosis.