Immulectin, an inducible C-type lectin from an insect, Manduca sexta, stimulates activation of plasma prophenol oxidase
Immulectin, an inducible C-type lectin from an insect, Manduca sexta, stimulates activation of plasma prophenol oxidase
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DOI：
10.1016/s0965-1748(99)00036-3
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发表时间：
1999-07-01
影响因子：
3.8
通讯作者：
Kanost, MR
中科院分区：
文献类型：
--
作者：
Yu, XQ;Gan, H;Kanost, MR
免疫凝集素是一种来自烟草天蛾 Manduca sexta 的 C 型凝集素，是从幼虫脂肪体 cDNA 文库中克隆的。免疫凝集素 cDNA 编码 309 个残基的多肽。通过注射灭活的革兰氏阳性或革兰氏阴性细菌或酵母来诱导免疫凝集素合成。注射细菌后，脂肪体中出现免疫凝集素mRNA，血淋巴中检测到免疫凝集素蛋白。免疫凝集素含有两个碳水化合物识别域。羧基末端碳水化合物识别结构域与美洲大蠊（Periplaneta americana）的脂多糖结合蛋白最相似（36% 同一性）。它还与各种哺乳动物 C 型凝集素的碳水化合物识别域具有 26-35% 的同一性。在注射细菌的幼虫的血淋巴中鉴定出两种免疫凝集素亚型。重组免疫凝集革兰氏阳性和革兰氏阴性细菌和酵母。向 M. sexta 血浆中添加重组免疫凝集素可刺激酚氧化酶的活化。免疫粘素与来自大肠杆菌的脂多糖的组合比单独的免疫粘素更快地激活酚氧化酶并且达到更高的水平，而脂多糖本身对酚氧化酶的激活几乎没有影响。针对细菌或真菌感染而合成的免疫凝集素可能有助于以类似于甘露糖结合蛋白（一种在哺乳动物先天免疫系统中发挥作用的 C 型凝集素）的方式触发 M. sexta 的保护性反应。 (C) 1999 Elsevier Science Ltd. 保留所有权利。
Immulectin, a C-type lectin from the tobacco hornworm, Manduca sexta, was cloned from a larval fat body cDNA library. The immulectin cDNA encodes a 309 residue polypeptide. Immulectin synthesis was induced by injection of killed gram-positive or gram-negative bacteria or yeast. After injection of bacteria, immulectin mRNA appeared in fat body and immulectin protein was detected in hemolymph. Immulectin contains two carbohydrate recognition domains. The carboxyl-terminal carbohydrate recognition domain is most similar (36% identity) to a lipopolysaccharide-binding protein from the American cockroach, Periplaneta americana. It also shares 26-35% identity to carbohydrate recognition domains of various mammalian C-type lectins. Two immulectin isoforms were identified in the hemolymph of bacteria-injected larvae. Recombinant immulectin agglutinated gram-positive and gram-negative bacteria and yeast. Addition of recombinant immulectin to M. sexta plasma stimulated activation of phenol oxidase. A combination of immulectin with lipopolysaccharide from E. coli activated phenol oxidase more rapidly and to a higher level than immulectin alone, whereas lipopolysaccharide by itself had little effect on phenol oxidase activation. Immulectin synthesized in response to bacterial or fungal infection may help to trigger protective responses in M. sexta in a manner similar to mannose-binding protein, a C-type lectin that functions in the mammalian innate immune system. (C) 1999 Elsevier Science Ltd. All rights reserved.