Pathogenesis of a nemia in Japanese bovine theileriosis

点击翻译按钮获取中文摘要

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.