Inhibition of ehrlichial infection using effective proteins from tick, Ixodes ovatus

1.对2只SPF比格犬接种从日本硬蜱(Ixodes Ovatus)中分离到的HF565埃立克氏菌。他们都没有临床症状，用白细胞DNA进行的聚合酶链式反应结果均为阴性。这些结果表明，狗没有感染HF565.2埃立克氏菌。无临床症状，接种后存活4周。大鼠接种HF565后1周可见肝细胞坏死、淋巴样细胞浸润等组织病理学改变。内皮细胞内也可见大量的桑拿囊泡。从肝、脾、肾、肺组织中提取的DNA进行聚合酶链式反应，结果均为阳性。在实验过程中，杠杆的损伤变轻。从外周血中提取DNA进行聚合酶链式反应均为阴性。这些结果表明，HF565可以感染大鼠，但在感染后3~4周内被清除。3.研究犬埃立克体感染犬体内细胞因子mRNA的表达。感染后3~8d检测外周血单个核细胞干扰素-γ和肿瘤坏死因子-γ的表达。感染后持续表达2个月以上。犬E.canis感染犬外周血单个核细胞后产生干扰素-γ。实验还证实，犬艾美耳球虫感染犬的外周血单核细胞对犬艾美耳球虫的体外生长有抑制作用。提示干扰素-γ在埃立克病毒感染免疫中具有重要作用。

1.Two SPF beagle dogs were inoculated with HF565, Ehrlichia which was isolated from Japanese tick (Ixodes ovatus). They had no clinical signs and results of PCR using DNA from white blood cells were all negative. These results suggested that dogs are not infected with Ehrlichia HF565.2.Ten rats were inoculated with HF565. They had no clinical signs and survived 4 weeks after inoculation. Histopathological changes such as necrosis of liver cells and infiltration of lymphoid cells were observed in the rats 1 week after inoculation of HF565. Many ehrlichial morulae were also observed mainly in endothelial cells. PCR using DNA from liver, spleen, kidney and lung showed positive results. The lesion of lever turned to be light during experiment. PCR using DNA from peripheral blood were all negative. These results suggest that HF565 could infect to rats but they were eliminated during 3 to 4 weeks after infection.3.Expression of dog cytokine mRNA in Ehrlichia canis-infected dogs were investigated. Interferon-γ (IFN-γ) and tumor necrosis factor-αmRNA were detected in peripheral blood mononuclear cells on 3 to 8 days after infection. The expression continued for more than 2 months after infection. Production of IFN-γ after infection of E.canis to dog peripheral blood mononuclear cells in vitro was confirmed. It was also confirmed that addition of peripheral blood mononuclear cells from E.canis-infected dog inhibited the growth of E.canis in vitro. These results suggested that IFN-γ has a very important role in immunity of ehrlichial infection.