演題詳細

一般口演 / Oral Session

一般口演 88 (Oral Session 88) :ITP・トロンボポエチン (ITP and Thrombopoietin)

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日程
2013年10月13日(日)
時間
09:15 - 10:45
会場
第13会場 / Room No.13 (札幌市教育文化会館 3F 研修室301)
座長・司会
宮崎 浩二 (Koji Miyazaki):1
1:北里大学医学部 血液内科学
 
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Analysis of thrombopoiesis in an antibody-induced immune-thrombocytopenic Xenopus model

演題番号 : OS-3-87

安川 賢 (Ken Yasukawa):1、谷崎 祐太 (Yuta Tanizaki):1,2、野村 一騎 (Ikki Nomura):3、大谷 崇仁 (Takato Otani):3、望月 瑶子 (Yoko Mochizuki):3、加藤 尚志 (Takashi Kato):1,3

1:Integrative Bioscience and Biomedical Engineering, Waseda University, Tokyo, Japan、2:Research Fellowships of Japan Society for the Promotion of Science、3:Department of Biology, School of Education, Waseda University, Tokyo, Japan

 

The mechanisms of immune-thrombocytopenia are complex. Thrombopoietin (TPO) is the key regulator of platelet production. It was reported that the patients administrated PEG-rHuMGDF become thrombocytopenia due to the development of neutralizing antibodies to endogenous TPO. In this typical case, the cause of production of neutralizing antibody is not clearly elucidated yet. In African clawed frog (Xenopus laevis), we have previously reported the thrombopoietic functions of Xenopus TPO (xlTPO) in vitro. However, the function of xlTPO in vivo is unclear. To generate anti-xlTPO polyclonal antibody, rabbit are immunized recombinant xlTPO expressed in Escherichia coli, and then we purified the antibodies by Protein A column chromatography. These antibodies specifically inhibited the formulation of thrombocytic colonies from liver cells on in vitro colony forming assay in the presence of xlTPO. To analyze the in vivo effects of the xlTPO, frogs were administrated anti-xlTPO polyclonal antibody (1.0 mg/kg B.W.) by intracardiac injection. After 4 days, anti-Xenopus thrombocytes monoclonal antibody positive cells in peripheral blood were decreased to 26.6% (±16.9%, p<0.01), and amount of these cells are recovered on day 6. We then analyzed the changes of the thrombocytic cells in the liver and spleen on the thrombocytopenic term and the convalescence. It is suggested that xlTPO is necessary for the homeostasis of thrombocyte number, but it is unnecessary for erythrocyte and leucocyte number. Finally, we discuss about the in vivo effects of xlTPO and its early thrombopoiesis.

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