Immulectin-2, a pattern recognition receptor that stimulates hemocyte encapsulation and melanization in the tobacco hornworm, Manduca sexta
Immulectin-2, a pattern recognition receptor that stimulates hemocyte encapsulation and melanization in the tobacco hornworm, Manduca sexta
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DOI：
10.1016/j.dci.2004.02.005
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发表时间：
2004-07-01
影响因子：
2.9
通讯作者：
Kanost, MR
中科院分区：
文献类型：
--
作者：
Yu, XQ;Kanost, MR
在昆虫中，包裹之后的黑化是抵御后生动物寄生虫的主要防御机制。然而，昆虫在发动免疫反应之前必须识别和区分非我。昆虫对病原体的识别是通过一组模式识别受体(PRRs)来完成的。PRRs与病原体的结合与多种免疫反应有关，包括吞噬、结节形成、包裹和酚氧化酶原激活。到目前为止，人们对PRRs识别病原体如何触发不同的免疫反应知之甚少。在这篇文章中，我们报道了一种C型凝集素imulectin-2，它促进了烟草角虫的包膜和黑化过程。在琼脂糖珠上包裹IMMLECTIN-2的重组羧基末端碳水化合物识别结构域(CRD2-II)，可以在体外促进血细胞对珠子的包裹，并在体内促进六分枝杆菌幼虫对珠子的黑化。重组CRD2-II也可直接与颗粒细胞和类卵泡细胞结合，但不与浆细胞或球状细胞结合。六条线虫幼虫血淋巴中的免疫凝集素-2与线虫线虫表面结合，重组CRD2-II直接与线虫和人类丝虫马来丝虫结合。CRD2-II与线虫结合可促进线虫体内黑化。我们的结果表明，免疫凝集素-2与寄生虫表面的结合可以触发六分枝杆菌的包膜和黑化反应。(C)2004爱思唯尔有限公司。保留所有权利。
In insects, encapsulation followed by melanization is a major defense mechanism against metazoan parasites. However, insects must recognize and differentiate nonself before they mount an immune response. Recognition of pathogens in insects is accomplished by a set of pattern recognition receptors (PRRs). Binding of PRRs to pathogens is linked to a variety of immune responses including phagocytosis, nodule formation, encapsulation, and prophenoloxidase activation. So far, little is known about how recognition of pathogens by PRRs triggers different immune responses. In this article, we report that immulectin-2, a C-type lectin, enhances encapsulation and melanization processes in the tobacco hornworm, Manduca sexta. Coating of agarose beads with recombinant carboxyl-terminal carbohydrate-recognition domain (CRD2-II) of immulectin-2 enhanced encapsulation of the beads in vitro by hemocytes and melanization of the beads in vivo in M. sexta larvae. Recombinant CRD2-II also directly bound to granular cells and oenocytoids, but not to plasmatocytes or spherule cells. Immulectin-2 in hemolymph of M. sexta larvae bound to the surface of a nematode, Caenorhabditis elegans, and recombinant CRD2-II directly bound to C. elegans and a human filarial nematode, Brugia malayi. Binding of CRD2-II to C. elegans enhanced melanization of the nematode in vivo. Our results suggest that binding of immulectin-2 to the surface of parasites can trigger encapsulation and melanization responses in M. sexta. (C) 2004 Elsevier Ltd. All rights reserved.