Efficiency of salivary gland invasion by malaria sporozoltes is controlled by rapid sporozoite destruction in the mosquito haemocoel
Efficiency of salivary gland invasion by malaria sporozoltes is controlled by rapid sporozoite destruction in the mosquito haemocoel
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DOI：
10.1016/j.ijpara.2006.12.007
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发表时间：
2007-05-01
影响因子：
4
通讯作者：
Vernick, Kenneth D.
中科院分区：
文献类型：
--
作者：
Hillyer, Julian F.;Barreau, Catherine;Vernick, Kenneth D.
为了成功地传播到脊椎动物宿主，疟疾子孢子必须从蚊子中肠迁移到唾液腺。在这里，使用纯化的子孢子接种到蚊子血腔，我们表明，唾液腺入侵是低效的，子孢子有一个狭窄的窗口唾液腺入侵的机会。只有19%的子孢子侵入唾液腺，所有的侵入都发生在8小时内，每小时约200个子孢子，在这段时间内未能侵入的子孢子迅速死亡并降解。然后，使用自然释放的子孢子从卵囊，我们表明，血淋巴流通过背血管促进适当的入侵。大多数蚊子循环子孢子的稳态数量较低，这是显着的，因为每个卵囊释放了数千个子孢子，并表明子孢子降解是一个快速的免疫过程，在血淋巴流量高的地区最有效。只有2%的冈比亚按蚊血细胞吞噬伯氏疟原虫子孢子，这一比率不足以解释子孢子清除的程度。超过95%的血细胞吞噬大肠杆菌或乳胶颗粒，表明它们未能隔离大量的子孢子不是由于不能进行吞噬作用。这些结果揭示了蚊子血腔内有效的子孢子杀灭和降解机制的运作，这极大地限制了蚊子唾液腺中感染性子孢子的数量。(c)2006年澳大利亚寄生虫学会由爱思唯尔有限公司出版。保留所有权利。
For successful transmission to the vertebrate host, malaria sporozoites must migrate from the mosquito midgut to the salivary glands. Here, using purified sporozoites inoculated into the mosquito haemocoel, we show that salivary gland invasion is inefficient and that sporozoites have a narrow window of opportunity for salivary gland invasion. Only 19% of sporozoites invade the salivary glands, all invasion occurs within 8 h at a rate of approximately 200 sporozoites per hour, and sporozoites that fail to invade within this time rapidly die and are degraded. Then, using natural release of sporozoites from oocysts, we show that haemolymph flow through the dorsal vessel facilitates proper invasion. Most mosquitoes had low steady-state numbers of circulating sporozoites, which is remarkable given the thousands of sporozoites released per oocyst, and suggests that sporozoite degradation is a rapid immune process most efficient in regions of high haemolymph flow. Only 2% of Anopheles gambiae haemocytes phagocytized Plasmodium berghei sporozoites, a rate insufficient to explain the extent of sporozoite clearance. Greater than 95% of haemocytes phagocytized Escherichia coli or latex particles, indicating that their failure to sequester large numbers of sporozoites is not due to an inability to engage in phagocytosis. These results reveal the operation of an efficient sporozoite-killing and degradation machinery within the mosquito haemocoel, which drastically limits the numbers of infective sporozoites in the mosquito salivary glands. (c) 2006 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.