Department of Entomology, Iowa State University, Ames, Iowa, USA.
Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
mSphere. 2021 Mar 31;6(2):e00136-21. doi: 10.1128/mSphere.00136-21.
Mosquitoes may feed multiple times during their life span in addition to those times needed to acquire and transmit malaria. To determine the impact of subsequent blood feeding on parasite development in , we examined parasite infection with or without an additional noninfected blood meal. We found that an additional blood meal significantly reduced immature oocyst numbers, yet had no effect on the human parasite These observations were reproduced when mosquitoes were fed an artificial protein meal, suggesting that parasite losses are independent of blood ingestion. We found that feeding with either a blood or protein meal compromises midgut basal lamina integrity as a result of the physical distention of the midgut, enabling the recognition and lysis of immature oocysts by mosquito complement. Moreover, we demonstrate that additional feeding promotes oocyst growth, suggesting that human malaria parasites exploit host resources provided with blood feeding to accelerate their growth. This is in contrast to experiments with , where the size of surviving oocysts is independent of an additional blood meal. Together, these data demonstrate distinct differences in species in evading immune detection and utilizing host resources at the oocyst stage, representing an additional, yet unexplored component of vectorial capacity that has important implications for the transmission of malaria. Mosquitoes must blood feed multiple times to acquire and transmit malaria. However, the impact of an additional mosquito blood meal following malaria parasite infection has not been closely examined. Here, we demonstrate that additional feeding affects mosquito vector competence; namely, additional feeding significantly limits infection, yet has no effect on infection of the human parasite Our experiments support that these killing responses are mediated by the physical distension of the midgut and by temporary damage to the midgut basal lamina that exposes immature oocysts to mosquito complement, while human malaria parasites are able to evade these killing mechanisms. In addition, we provide evidence that additional feeding promotes oocyst growth. This is in contrast to , where oocyst size is independent of an additional blood meal. This suggests that human malaria parasites are able to exploit host resources provided by an additional feeding to accelerate their growth. In summary, our data highlight distinct differences in malaria parasite species in evading immune recognition and adapting to mosquito blood feeding. These observations have important, yet previously unexplored, implications for the impact of multiple blood meals on the transmission of malaria.
蚊子在其生命周期中除了需要获取和传播疟疾之外，还可能多次吸血。为了确定随后的吸血对疟原虫发育的影响，我们检查了有无额外未感染的血餐的情况下寄生虫的感染情况。我们发现，额外的血餐显着减少了不成熟的卵囊数量，但对人类寄生虫没有影响。当蚊子喂食人工蛋白质餐时，观察到了这些观察结果的重现，这表明寄生虫的损失与血液摄入无关。我们发现，无论是用血还是蛋白质喂养都会破坏中肠基底膜的完整性，因为中肠的物理膨胀，从而使蚊子补体能够识别和溶解不成熟的卵囊。此外，我们证明额外的喂养会促进卵囊的生长，这表明人类疟原虫利用宿主资源来加速其生长，而这是通过吸血来提供的。这与与实验形成对比，在实验中，幸存的卵囊的大小与额外的血液摄入无关。这些数据共同表明，在逃避免疫检测和利用卵囊阶段的宿主资源方面，与疟原虫不同，这是蚊子传播能力的另一个，尚未探索的组成部分，对疟疾的传播具有重要意义。蚊子必须多次吸血才能获取和传播疟疾。但是，疟疾寄生虫感染后额外的蚊子血餐的影响尚未得到密切研究。在这里，我们证明了额外的喂养会影响蚊子的媒介能力；即，额外的喂养显着限制了感染，但对感染人类寄生虫没有影响。我们的实验支持这些杀伤反应是由中肠的物理膨胀和暂时破坏中肠基底膜介导的，这使不成熟的卵囊暴露于蚊子补体中，而人类疟原虫能够逃避这些杀伤机制。此外，我们提供了证据表明，额外的喂养会促进卵囊的生长。这与疟原虫不同，其中卵囊的大小与额外的血液摄入无关。这表明人类疟原虫能够利用额外的血液喂养提供的宿主资源来加速其生长。总之，我们的数据突出了疟原虫在逃避免疫识别和适应蚊子吸血方面的明显差异。这些观察结果对于多次血液摄入对疟疾传播的影响具有重要的，但以前尚未探索过的意义。
