LDLR and infection: Studies in low density receptor deficient mice (LDLR-/-) mice, which suffer from increased circulating levels of LDL-cholesterol, showed that LDLR-/- mice survive longer and have lower levels of circulating proinflammatory cytokine concentrations after infection with the Gram-negative bacteria Salmonella typhimurium and Klebsiella pneumoniae [7, 8].