Hillyer Julián F, Schmidt Shelley L, Christensen Bruce M
Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, 1656 Linden Drive, Madison, WI 53706, USA.
Cell Tissue Res. 2003 Jul;313(1):117-27. doi: 10.1007/s00441-003-0744-y. Epub 2003 Jun 28.
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.
蚊子是重要的疾病传播媒介。这些昆虫通过强大的细胞和体液免疫反应来应对入侵的生物体，这些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。在当前的研究中，我们通过形态学（超微结构）、凝集素结合、酶活性、免疫细胞化学和功能对骚扰阿蚊的血细胞进行了表征。我们发现了四种血细胞类型：粒细胞、绛色细胞、脂肪血细胞和血小板样细胞。粒细胞含有酸性磷酸酶活性，并与外源凝集素苹果蜗牛凝集素、雪花莲凝集素和麦胚凝集素结合。接种细菌后，粒细胞早在暴露后5分钟就产生了强烈的吞噬反应。细菌还引发了血细胞介导的黑化反应。酚氧化酶是黑化途径中的限速酶，仅存在于绛色细胞和许多包裹细菌的黑色包囊中。针对不同细菌的免疫反应并不相同；革兰氏阴性大肠杆菌主要被吞噬，而革兰氏阳性藤黄微球菌则被黑化。这些研究表明血细胞是抵御细菌的主要防线。
