| Project/Area Number |
08670276
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
寄生虫学(含医用動物学)
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| Research Institution | NIIGATA UNIVERSITY |
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Principal Investigator |
SEKIKAWA Hiroho Niigata University, School of Medicine, Assistant Professor, 医学部, 助教授 (50018694)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Hisami Niigata University, School of Medicine, Research Associate, 医学部, 助手 (50143756)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | Hepatic lymphocyte / Extrathymic T cells / Host defense / Murine Malaria / Self-reactive forbidden clones / Cytotoxicity against malaria infected red blood cells / Leishmaniasis / Visceral larve migrans / 原虫感染 / ネズミマラリア / 蠕虫感染 / イヌ蛔虫 / IL-4産生細胞 / サイトカイン産生細胞 / NK細胞 |
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| Research Abstract |
In a series of recent studies, we have demonstrated that the liver is an important immune organs that produces extrathymic T cells in mice and humans. These T cells are distinguished from thymus-derived T cells by many properties. Some of these properties include the intermediate density of TCR-CD3 complex on their surface and constitutive expression of interleukin-2Rbeta-chain.
The development of protective immunity to parasitic infection requires the presence of T cells. In this project, we investigated the role of extrathyinic T cells in mice during infection with murine malaria (P.yoelli), Leishmania (L.major) and Ascaris larvae (T.canis).
1) Visceral larva migrans model In early phase of T.canis infection (on day 1), unique population of hepatic T cells were observed, i.e., double-positive (DP) CD4^+CD8^+ cells. The proportion of extrathymic T cells was also elevated therafter.
2) Leishmaniasis model In mice infected with L.major, the levels of extrathymic T cells in the liver increased. The produciblity of IL-4 in these T cells elevated in the liver. These observations indicate that the induction of Th2 type immune response is dominant in murine Leishmaniasis.
3) Murine malaria model Expansion of extrathymic T cells were observed with flowcytometric analysis of lymphocytes from liver, spleen and thymus. They possessed self-reactive forbidden clones and cytotoxicity against parasitized RBC.Deletion of TL-2Rbeta^+ cells resulted in early exacerbation of infection of the non-lethal strain malaria. These data indicate the extrathymic T cells play a role during the erythrocytic stage of the rodent malaria infection.
These results suggest that the expanding extrathymic T cells in various organs play an important role of protective immunity during parasitic infection.
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