Inhibition of ehrlichial infection using effective proteins from tick, Ixodes ovatus

• Project/Area Number: 16580257
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied veterinary science
• Research Institution: Osaka Prefecture University
• Principal Investigator: TAJIMA Tomoko Osaka Prefecture University, Graduate School of Life & Environmental Sciences, Research Associate, 生命環境科学研究科, 助手 (90173145)
• Co-Investigator(Kenkyū-buntansha): KAWAHARA Makoto Nagoya City Public Health Research Institute, Senior Researcher, 微生物部74, 主任研究員 ; ONUMA Misao Hokkaido University, Graduate School of Veterinary Medicine, Professor, 獣医学研究科, 教授 (70109510) ; KUWAMURA Mitsuru Osaka Prefecture University, Graduate School of Life & Environmental Sciences, Assistant Professor, 生命環境科学研究科, 講師 (20244668)
• Project Period (FY): 2004 – 2005
• Project Status: Completed (Fiscal Year 2005)
• Budget Amount: ¥3,700,000 (Direct Cost: ¥3,700,000); Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000); Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
• Keywords: Ehrlichia / tick / dog / cytokine / interferon gamma / ヤマトマダニ

Research Abstract

1.Two SPF beagle dogs were inoculated with HF565, Ehrlichia which was isolated from Japanese tick (Ixodes ovatus). They had no clinical signs and results of PCR using DNA from white blood cells were all negative. These results suggested that dogs are not infected with Ehrlichia HF565.
2.Ten rats were inoculated with HF565. They had no clinical signs and survived 4 weeks after inoculation. Histopathological changes such as necrosis of liver cells and infiltration of lymphoid cells were observed in the rats 1 week after inoculation of HF565. Many ehrlichial morulae were also observed mainly in endothelial cells. PCR using DNA from liver, spleen, kidney and lung showed positive results. The lesion of lever turned to be light during experiment. PCR using DNA from peripheral blood were all negative. These results suggest that HF565 could infect to rats but they were eliminated during 3 to 4 weeks after infection.
3.Expression of dog cytokine mRNA in Ehrlichia canis-infected dogs were investigated. Interferon-γ (IFN-γ) and tumor necrosis factor-αmRNA were detected in peripheral blood mononuclear cells on 3 to 8 days after infection. The expression continued for more than 2 months after infection. Production of IFN-γ after infection of E.canis to dog peripheral blood mononuclear cells in vitro was confirmed. It was also confirmed that addition of peripheral blood mononuclear cells from E.canis-infected dog inhibited the growth of E.canis in vitro. These results suggested that IFN-γ has a very important role in immunity of ehrlichial infection.

Research Products

• [Journal Article] Novel genetic variants of Anaplasma phagocytophilum, Anaplasma bovis, Anaplasma centrale, and a novel Ehrlichia sp, in wild deer and ticks on two major islands in Japan. (2006)
  • Author(s): Kawahara, M., Rikihisa, Y., Lin, Q., Isogai, E., Tahara, K., Itagaki, A., Hiramitsu, Y., Tajima, T.
  • Journal Title: Appl.Environ.Microbiol. 72,2 Pages: 1102-1109
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Two serine protease inhibitors (serpins) that induce a bovine protective immune response against Rhipicephalus appendiculatus ticks. (2006)
  • Author(s): Imamura, S., Namangala, B., Tajima, T., Tembo, M.E., Yasuda, J., Ohashi, K., Onuma, M.
  • Journal Title: Vaccine 24, Pages: 2230-2237
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Novel genetic variants of Anaplasma phagocytophilum, Anaplasma bovis, Anaplasma centrale, and a novel Ehrlichia sp, in wild deer and ticks on two major islands in Japan. (2006)
  • Author(s): Kawahara, M., Rikihisa, Y., Lin, Q., Isogai, E., Tahara, K., Itagaki, A., Hiramitsu, Y., Tajima, T.
  • Journal Title: Appl.Environ.Microbiol. 72 Pages: 1102-1109
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Two serine protease inhibitors (serpins) that induce a bovine protective immune response against Rhipicephalus appendiculatus ticks. (2006)
  • Author(s): Imamura, S., Namangala, B., Tajima, T., Tembo, M.E., Yasuda, J., Ohashi, K., Onuma, M.
  • Journal Title: Vaccine 24 Pages: 2230-2237
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Novel genetic variants of Anaplasma phagocytophilum, Anaplasma bovis, Anaplasma centrale, and a novel Ehrlichia sp. In wild deer and ticks on two major islands in Japan (2006)
  • Author(s): Kawahara, M., Rikihisa, Y., Lin, Q., Isogai, E., Tahara, K., Itagaki, A., Hiramitsu, Y., Tajima, T.
  • Journal Title: Appl.Env.Micobiol. 72 Pages: 1102-1109
• [Journal Article] Cytokine responses in dogs infected with Ehrlichia canis Oklahoma strain. (2005)
  • Author(s): Tajima, T., Rikihisa, Y.
  • Journal Title: Ann.N.Y.Acad.Sci. 1063 Pages: 429-432
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] Cytokine responses in dogs infected with Ehrlichia canis Oklahoma strain (2005)
  • Author(s): Tajima, T., Rikihisa, Y.
  • Journal Title: Ann.N.Y.Acad.Sci. 1063 Pages: 429-432