Complement is the first line of the host innate immune response against bacterial and viral infections; however, its role in the development of the malaria liver stage remains undefined. We found that sporozoite infection by either a mosquito bite or intravenous injection activated systemic complement, but neither depletion of C3 nor knockout of C3 had a significant effect on malaria liver stage development. Incubation of mouse serum with trypsin-treated sporozoites, but not naive sporozoites, led to the deposition of a membrane attack complex (MAC) on the surface of sporozoites and greatly reduced the number of exo-erythrocytic forms (EEF). Further studies have shown that the recruitment of complement H factor (CFH) may be associated with the prevention of MAC deposition on the surface of naïve sporozoites. Our data strongly suggest that sporozoites can escape complement attacks and provide us with a novel strategy to prevent malaria infection.

中文翻译：

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疟疾子孢子逃避宿主补体攻击

补体是宿主针对细菌和病毒感染的先天免疫反应的第一道防线；然而，其在疟疾肝脏阶段发展中的作用仍不清楚。我们发现，通过蚊虫叮咬或静脉注射引起的子孢子感染会激活全身补体，但 C3 的耗竭和 C3 的敲除都对疟疾肝阶段的发展没有显着影响。将小鼠血清与经胰蛋白酶处理的子孢子（而非幼稚子孢子）一起孵育，导致膜攻击复合物（MAC）沉积在子孢子表面，并大大减少了外红细胞形式（EEF）的数量。进一步的研究表明，补体 H 因子 (CFH) 的募集可能与防止 MAC 在幼稚子孢子表面沉积有关。我们的数据强烈表明，子孢子可以逃避补体攻击，并为我们提供了预防疟疾感染的新策略。