Frevert Ute
Department of Medical and Molecular Parasitology, New York University School of Medicine, 341 E 25 Street, New York, NY 10010, USA.
Trends Parasitol. 2004 Sep;20(9):417-24. doi: 10.1016/j.pt.2004.07.007.
Malaria infection is caused by sporozoites, the life cycle stage of Plasmodium that is transmitted by female anopheline mosquitoes. The inoculated sporozoites migrate in the skin, enter a capillary and use the bloodstream for the long haul to the liver. Here, the parasites invade hepatocytes and differentiate to thousands of merozoites that specifically infect red blood cells. Hepatocytes, however, are not directly accessible to sporozoites entering the liver sinusoid. The liver phase of the malaria life cycle can occur only if the parasites first cross the layer of sinusoidal cells that line the liver capillaries. Experimental observations show that sporozoite entry into the liver parenchyma involves a complex cascade of events, from binding to extracellular matrix proteoglycans via passage through Kupffer cells and transmigration through several hepatocytes, until the final host cell is found. By choosing the liver as their initial site of replication, Plasmodium sporozoites can exploit the tolerogenic properties of this unique immune organ to evade the host's immune response.
疟疾感染是由子孢子引起的，子孢子是疟原虫的生命周期阶段，由雌性按蚊传播。接种的子孢子在皮肤中迁移，进入毛细血管，并利用血液循环长途跋涉到达肝脏。在这里，寄生虫侵入肝细胞并分化为数千个裂殖子，这些裂殖子专门感染红细胞。然而，进入肝血窦的子孢子无法直接接触到肝细胞。只有当寄生虫首先穿过排列在肝毛细血管内的窦状细胞层时，疟疾生命周期的肝脏阶段才会发生。实验观察表明，子孢子进入肝实质涉及一系列复杂的事件，从通过库普弗细胞与细胞外基质蛋白聚糖结合，到穿过几个肝细胞进行迁移，直到找到最终的宿主细胞。通过选择肝脏作为它们最初的复制部位，疟原虫子孢子可以利用这个独特免疫器官的致耐受性特性来逃避宿主的免疫反应。
