| Co-Investigator(Kenkyū-buntansha) |
KAKUDA Tsutomu KITASATO UNIVERSITY, SCHOOL OF VETERINARY MEDICINE AND ANIMAL SCINECES, ASSISTANT PROFESSOR, 獣医畜産学部, 助手 (80317057)
TAKAI Shinji KITASATO UNIVERSITY, SCHOOL OF VETERINARY MEDICINE AND ANIMAL SCINECES, ASSOCIATE PROFESSOR, 獣医畜産学部, 助教授 (80137900)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Immunization with live virulent R. equi conferred protection against virulent organisms in mice, whereas heat-killed virulent or live avirulent bacteria offered no protection. The protective immunity was observed 5 days after the sublethal inoculation with live ATCC 33701, and the most effective clearance of challenged bacteria was found in the mice primed at 9 days before the challenge. Immune memory by the live virulent R. equi reduced for a few weeks. The purpose of this study is to elucidate the mechanism of the reduction of R. equi-specific immune memory in mice model. To measure the production of IFN-γ and TNF-α from immune spleen cells, mice were immunized with live virulent R. equi for 7, 17, 21, and 28 days. The highest production of IFN-γ and TNF- a from immune spleen cells after stimulation with R. equi antigens was observed in mice immunized for 7 days, and the production level of the spleen cell from mice immunized for 17 days became the same as that from normal mice. Sple
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en cells from mice immunized for 7 or 14 days were transfer to normal mice and the mice were challenged with virulent R. equi. The transfer immunity was effective in mice received spleen cell primed for 7 days, but not for 14 days. Immunized mice for 7 or 21 days with virulent R. equi were inoculated with anti-IL10 monoclonal antibody, and then challenged with virulent R. equi. There was no effect of anti-IL-10 antibody on the clearance of R. equi in the organs as compared with those of none-treated immune mice. On the other hand, in vitro experiment with anti-IL-10 monoclonal antibody showed effective function of IL-10 on the production of IFN-γ and TNF-α from immune spleen cells. Expression of CD44, CD62L, and CD45RB antigens on the spleen cells were analyzed by flow cytometory analysis using anti-CD44, CD62L, and CD45RB antibodies. However, there was no change between spleen T cells from immunized mice for 7 and 21 days. In conclusion, IL-10 might play a key role in the establishment and reduction of immune memory in R. equi infection in mice, however, the mechanism of inactivation or tolerance of T cells by R. equi infection remain unclear. Less
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