Molecular pathogenetic analysis of blood vessels in toxoplasmic retinochoroiditis

弓形虫可导致严重的危及生命的疾病，特别是在免疫功能低下的患者中。在体内，速殖子通过血流和/或淋巴管从肠道传播到各种器官。尽管弓形虫能够在体内感染多种细胞类型并导致视网膜血管炎，但目前尚不清楚弓形虫栖息的外周血白细胞(PBL)中哪些亚群在弓形虫传播中起重要作用，哪些分子在视网膜血管炎中起重要作用。以干扰素γ基因敲除小鼠为免疫缺陷宿主模型，分析了体内细胞敏感性和血液中弓形虫的感染性。用10个弓形虫包囊经口感染同龄的野生型(WT)C57BL/6和WT BALB/c小鼠和GKO小鼠。感染后第7天，用磁性细胞分选系统将WBC分离成不同的亚群。用定量竞争聚合酶链式反应(QC-PCR)检测弓形虫的丰度。在WT和GKO小鼠中，所有WBC中都检测到弓形虫DNA，原虫的感染力没有差异。GKO WBC各亚群的原虫丰度均远高于WT小鼠。然后，将这些细胞注射到同一背景WT小鼠的腹膜腔内。用QC-PCR法检测注射PBL后4周小鼠脑内PI、弓形虫DNA。注射PBL后4周的小鼠脑内均可检出弓形虫DNA。尽管所有弓形虫感染小鼠的PBL亚群都具有体内感染能力，但不同PBL亚群之间的感染能力存在一定差异。我们现在正在分析被弓形虫感染的视网膜上的附着分子。

Toxoplasma gondii can cause severe, life-threatening disease, especially in immunocompromised patients. In vivo, tachyzoites are disseminated from the gut to a variety of organs by the blood stream and/or lymphatic vessels. Although Toxoplasma is capable of infecting a wide range of cell types in vivo and causes the retinal vasculitis, it is still uncertain as to which subsets of peripheral blood leukocytes (PBL) where T.gondii inhabits play an important role in dissemination of T.gondii and which molecules play an important role in retinal vasculitis. We analyzed the in vivo cell susceptibility and infectivity of T.gondii in the blood using interferon y knockout (GKO) mice as a model of immunocompromised hosts.T.gondii in the blood using interferon γ knockout (GKO) mice as a model of immunocompromised hosts. Wild type (WT) C57BL/6 and WT BALB/c mice and GKO mice of the same age with both backgrounds were infected perorally with 10 cysts of T.gondii. On day 7 post infection (PI) WBC were separated into subsets using a magnetic cell-sorting system. T.gondii abundance was evaluated with a quantitative competitive polymerase chain reaction assay (QC-PCR).In both WT and GKO mice T.gondii DNA was detected in all WBC and there was no differences in infectivity of the protozoan. The abundance of protozoan in each GKO WBC subset was much higher than in WT mice.Next, these cells were injected into the peritoneal cavity of the same background WT mice. Four weeks PI, T.gondii DNA was analyzed in the brain of the PBL injected mice by QC-PCR. Toxoplasma gondii DNA was detected in all brains of PBL-injected mice at 4 weeks PI. There were some differences in infectious ability among PBL subsets, although all subsets of PBL from T.gondii infected mice had the infectious ability in vivo. We are now analyzing the adherent molecules from the retina which was infected by T.gondii.