Pathogenesis of a nemia in Japanese bovine theileriosis

由红细胞内原生动物东方泰勒虫（Theileria orientes）引起的日本牛泰勒虫病（Japanese bovine theileriosis）的主要临床症状是贫血，但贫血的潜在发病机制尚不清楚。本研究从活性氧对红细胞（RBC）产生氧化应激的角度阐明了T细胞贫血的发生机制，结果发现：（1）T细胞贫血发生过程中，活性氧对红细胞的氧化应激作用与T细胞的氧化应激有关;结果表明：（1）红细胞免疫球蛋白G（IgG）抗体与红细胞的结合率随贫血的发生而增加;（2）红细胞免疫球蛋白G（IgG）抗体与经氧化剂处理的红细胞的结合率高于未经氧化剂处理的红细胞;（3）红细胞表面磷脂酰丝氨酸（PS）的表达随贫血的发生而增加;经氧化剂处理的红细胞与未经氧化剂处理的红细胞相比，在氧化剂处理的红细胞表面出现了明显的PS;红细胞内过氧化氢水平随贫血的发展而显著升高;在东方蜱感染的牛中，海因茨小体形成的水平随着贫血的发展成比例地增加;和（6）从感染牛的外周血中获得的巨噬细胞与来自未感染牛的巨噬细胞相比表现出增加的红细胞吞噬活性。红细胞氧化损伤的增加，在日本牛泰勒虫病贫血的发展中起重要作用。

The primary clinical symptom of Japanese bovine theileriosis, caused by the intraerythrocytic protozoan Theileria orientails, is anemia, but the underlying pathogenesis of the anemia still unknown. This study was carried out to clarify the mechanism of this anemia's development from the viewpoint of oxidative stress to red blood cells (RBC) exerted by reactive oxygen species.The new findings of this study are as follows : (1) during the progression of anemia in T. orientalis-infected cattle, the binding of immunoglobulin G (IgG) antibody to RBC showed a proportionate increase with the development of anemia; (2) binding of IgG in infected serum to oxidant-treated RBC was higher than that to untreated RBC;(3) phosphatidylserine (PS) expression on the surface of RBC in infected cattle began to increase markedly during the onset of anemia : the oxidant-treated RBC were compared with untreated RBC of the same infected individual, with remarkable appearance of PS on the surface of oxidant-treated RBC; (4) during the onset of anemia in T. orlentalis-infected cattle, peroxide levels, as indicator of intraerythrocytic oxidation, increased markedly with the development of anemia; (5) during the progression of anemia in T. orientalis-infected cattle, the levels of Heinz body formation increased in proportion with the development of anemia ; and (6) macrophages obtained from peripheral blood of infected cattle exhibited increased erythrophagocytic activity compared to those from non-infected cattle.In this study, it was revealed from the biochemical analysis of RBC that oxidative stress, i.e., an increase in oxidative damage to RBC, plays an important role in the development of anemia in Japanese bovine theileriosis.