Through monthly intraperitoneal injections of CpG oligodeoxynucleotides (CpG ODN), a TLR9 agonist, in three different mouse models of AD (Tg2576, 3xTg and Tg-SwDI mice), significant cognitive improvement and a reduction in fibrillar and soluble Aβ were noted. The gene discussed is TLR9; the disease is Alzheimer disease.