OMP and atherosclerosis: Yukiko et al. found that nasal immunization of ApoE knock-out mice with 40 kDa outer membrane protein (OMP) of P. gingivalis reduced relevant atherosclerosis symptoms (Koizumi et al., 2009), Furthermore, Takashi et al. used CpG oligodeoxynucleotides (ODN) as an adjunctive together with 40kDa OMP (Takeuchi, Hashizume-Takizawa & Kobayashi, 2017).