| Project/Area Number |
01570247
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
細菌学
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| Research Institution | University of Occupational and Environmental Health, Japan |
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Principal Investigator |
YOSHIDA Shin-ichi University of Occupational and Environmental Health, Japan, Department of Microbiology, Associate Professor, 医学部, 助教授 (60128113)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1990: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1989: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Legionella pneumophila / Intracellular parasite / Protective immunity / Natural resistance / Macrophage / Immunogenetics / Interferon-gamma / LPS response / コンジェニックマウス / LPSレスポンス / 感染 / 感染防御 / マウス |
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| Research Abstract |
Species difference in the susceptibility to Legionella Pneumophila infection between guinea pigs and mice were studied and following results were obtained.
1. Guinea pigs were susceptible to L. Pneumophila infection (LD_<50>=7.6x10^4) and the becteria grew well in guinea pig macrophages in vitro. The most important protection in guinea pigs was assumed by macrophages which were activated by IFN-gamma produced in an early phase ofinfection.
2. C57BL/6 mice were resistant to L. Pneumophila infection (LD_<50>=7.3x10^7) and its macrophages did not permit the intracellular growth of the bacteria.
3. The bacteria multiplied in macrophages of A/J mice by 100-fold 2 days after in vitro phagocytosis. LD_<50> of A/J mice was 2.9x10^7 ; that was twofifths of C57BL/6. When anti-IFN-gamma antibody was administered into A/J mice, the organism significantly proliferated in liver, spleen and lungs. This implied that IFN-gamma production in very early phase of infection plays an important role in the protection.
4. Genetic analysis revealed that murine macrophages natural resistance is controlled by a single gene located on chromosome 15. We designated it as Lgn-1.
5. It was made clear that Lps gene also regulates the natural resistance of macrophages against L. Pneumophila. In the macrophages of LPS-low responder mice, the organism could proliferate better than in macrophages of LPS-high responder mice.
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