Plasmodial Proteins Expressed on The Surface of Infected Hepatocytes

为了提高子孢子体的体外感染效率，我们建立了小规模的原代肝细胞培养方法。将蚊子的腹腔腺、胸腺和唾液腺分离，每隔一天血餐后计数感染子孢子的数量。血餐后12天，从腹腔子孢子的数量最多。血餐后第18天，从胸腺和唾液腺获得的子孢子数最多。血餐后14~16天获得的子孢子对小鼠具有感染性。为了寻找获得大量子孢子的更好的实验条件，我们以DBA/1和C5缺陷的DBA/2小鼠为实验宿主，测定补体对疟疾寄生虫对蚊虫感染性的影响。饲喂DBA/1小鼠的卵囊对斯氏按蚊的感染力明显低于饲喂DBA/2小鼠的斯氏按蚊。DBA/2小鼠注射DBA/1热灭活血清不能降低卵囊的感染力。与对照组相比，DBA/2小鼠注射新鲜DBA/1血清后，其感染性显著降低。此外，用人C5恢复的雄性DBA/2小鼠血清显著降低了感染性。与传染性的降低相反，受感染的蚊子数量并没有减少。总之，小鼠血清中补体的替代途径显著降低了约氏疟原虫对斯氏疟原虫的感染力，但并未消除。感染力的降低主要是由于受精卵不能转化为蚊子中肠内的动细胞。DBA/2小鼠可能是获得大量子孢子进行体外感染的合适小鼠品系。

We established the small scale method of primary hepatocyte culture, in order to increase the efficiency of in vitro infection of sporozoites. The abdominal cavity and thorax and salivary glands of the mosquitoes were separated each other, and then the infected numbers of sporozoites were counted every other day after blood meal. The number of sporozoites obtained from the abdominal cavity were maximal 12 days after blood meal. The number of sporozoites obtained from the thorax and salivary gland were maximal 18 days after blood meal. The sporozoites obtained 14 to 16 days after blood meal were infectious to mice. To look for the better experimental conditions for obtaining a lot of sporozoites, we used DBA/1 and C5-deficient DBA/2 mice for the experimental host to determine the effects of complement on the infectivity of malaria parasites to mosquitoes. The infectivity of oocysts to Anopheles stephensi fed on DBA/1 mice was significantly less than those fed on DBA/2 mice. Heat inactivated DBA/1 sera injected into DBA/2 mice did not reduce the infectivity of oocysts. By comparison to these controls, fresh DBA/1 sera injected into DBA/2 mice significantly reduced the infectivity. Moreover, male DBA/2 mouse sera restored with human C5 significantly reduced the infectivity. In contrast to the reduction of infectivity, the numbers of infected mosquitoes were not reduced. In conclusion, the alternative pathway of complement in the mouse serum significantly reduced, but did not eliminate, the infectivity of Plasmodium yoelii to A.stephensi. The reduction of the infectivity is mainly due to the inability of the zygote to transform into the ookinete in the mosquito midgut. And DBA/2 mouse seems to be a suitable mouse strain to obtain a lot of sporozoites for in vitro infection.