Hemocyte-mediated phagocytosis and melanization in the mosquito Armigeres subalbatus following immune challenge by bacteria
Hemocyte-mediated phagocytosis and melanization in the mosquito Armigeres subalbatus following immune challenge by bacteria
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DOI：
10.1007/s00441-003-0744-y
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发表时间：
2003-07-01
影响因子：
3.6
通讯作者：
Christensen, BM
中科院分区：
文献类型：
--
作者：
Hillyer, JF;Schmidt, SL;Christensen, BM
蚊子是重要的疾病传播媒介。这些昆虫对入侵的生物体有强烈的细胞和体液免疫反应，与脊椎动物的免疫系统有许多相似之处。这些反应的强度和特异性与蚊子传播疾病的能力直接相关。在目前的研究中，我们的特点是血细胞的形态（超微结构），凝集素结合，酶活性，免疫细胞化学和功能的阿蚊subalbatus。我们发现了四种血细胞类型：粒细胞、类卵细胞、脂肪血细胞和类血小板细胞。粒细胞含有酸性磷酸酶活性，并结合外源凝集素苹果凝集素，雪花莲凝集素，麦胚凝集素。细菌接种后，粒细胞安装了一个强大的吞噬反应，早在5分钟后xexadium。细菌还引起血细胞介导的黑化反应。酚氧化酶是黑化途径中的限速酶，仅存在于oenocytoids和许多包裹细菌的黑色素囊中。针对不同细菌的免疫应答不相同;革兰氏（-）大肠杆菌主要被吞噬，革兰氏（+）藤黄微球菌被黑化。这些研究表明血细胞是抵抗细菌的主要防线。
Mosquitoes are important vectors of disease. These insects respond to invading organisms with strong cellular and humoral immune responses that share many similarities with vertebrate immune systems. The strength and specificity of these responses are directly correlated to a mosquito's ability to transmit disease. In the current study, we characterized the hemocytes (blood cells) of Armigeres subalbatus by morphology (ultrastructure), lectin binding, enzyme activity, immunocytochemistry, and function. We found four hemocyte types: granulocytes, oenocytoids, adipohemocytes, and thrombocytoids. Granulocytes contained acid phosphatase activity and bound the exogenous lectins Helix pomatia agglutinin, Galanthus nivalis lectin, and wheat germ agglutinin. Following bacteria inoculation, granulocytes mounted a strong phagocytic response as early as 5 min postexposure. Bacteria also elicited a hemocyte-mediated melanization response. Phenoloxidase, the rate-limiting enzyme in the melanization pathway, was present exclusively in oenocytoids and in many of the melanotic capsules enveloping bacteria. The immune responses mounted against different bacteria were not identical; gram(-) Escherichia coli were predominantly phagocytosed and gram(+) Micrococcus luteus were melanized. These studies implicate hemocytes as the primary line of defense against bacteria.