Daily Plasmodium yoelii infective mosquito bites do not generate protection or suppress previous immunity against the liver stage.
Daily Plasmodium yoelii infective mosquito bites do not generate protection or suppress previous immunity against the liver stage.
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DOI：
10.1186/1475-2875-10-97
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发表时间：
2011-04-18
期刊：
影响因子：
3
通讯作者：
Rodriguez A
中科院分区：
文献类型：
--
作者：
Pollock T;Leitao R;Galan-Rodriguez C;Wong KA;Rodriguez A
尽管长期且频繁地接触疟原虫，但自然受到疟原虫感染的人群并未获得针对这种寄生虫肝脏阶段的完全保护。然而，反复暴露于辐射减毒子孢子后，可以实现针对疟原虫肝期的无菌免疫力。这种不同反应的原因在很大程度上仍不清楚，但血液阶段疟原虫感染的抑制作用已被认为是缺乏肝脏阶段保护的原因。使用约氏疟原虫 17XNL，比较了每天被正常或受辐射蚊子叮咬的小鼠产生的反应。还研究了每天感染的蚊子叮咬对先前针对约氏疟原虫肝脏阶段进行免疫的小鼠的影响。据观察，虽然正常受感染的蚊子的叮咬不会产生强烈的抗体反应和保护，但受辐射的蚊子的叮咬会产生高水平的抗子孢子抗体并防止肝期疟原虫感染。每天接触受感染的蚊虫叮咬并不会消除之前使用实验性肝阶段疫苗获得的保护作用。受辐射的约氏疟原虫感染的蚊子与正常的约氏疟原虫感染的蚊子产生的肝期免疫本质上是不同的，可能是因为正常蚊子叮咬但未受辐射后发生了血液期感染。虽然感染性蚊虫叮咬不会诱发保护性肝脏阶段反应，但它们也不会干扰先前获得的肝脏阶段保护性反应，即使它们会诱发完全血液阶段感染。考虑到最近生产的抗疟疾疫苗仅能提供部分针对感染的保护，令人鼓舞的是，至少在小鼠模型中，随后的接触和感染寄生虫不会对免疫力产生负面影响。
Human populations that are naturally subjected to Plasmodium infection do not acquire complete protection against the liver stage of this parasite despite prolonged and frequent exposure. However, sterile immunity against Plasmodium liver stage can be achieved after repeated exposure to radiation attenuated sporozoites. The reasons for this different response remain largely unknown, but a suppressive effect of blood stage Plasmodium infection has been proposed as a cause for the lack of liver stage protection. Using Plasmodium yoelii 17XNL, the response generated in mice subjected to daily infective bites from normal or irradiated mosquitoes was compared. The effect of daily-infected mosquito bites on mice that were previously immunized against P. yoelii liver stage was also studied. It was observed that while the bites of normal infected mosquitoes do not generate strong antibody responses and protection, the bites of irradiated mosquitoes result in high levels of anti-sporozoite antibodies and protection against liver stage Plasmodium infection. Exposure to daily infected mosquito bites did not eliminate the protection acquired previously with a experimental liver stage vaccine. Liver stage immunity generated by irradiated versus normal P. yoelii infected mosquitoes is essentially different, probably because of the blood stage infection that follows normal mosquito bites, but not irradiated. While infective mosquito bites do not induce a protective liver stage response, they also do not interfere with previously acquired liver stage protective responses, even if they induce a complete blood stage infection. Considering that the recently generated anti-malaria vaccines induce only partial protection against infection, it is encouraging that, at least in mouse models, immunity is not negatively affected by subsequent exposure and infection with the parasite.