Shandong Marine Fisheries Research Institute, Yantai 264006, China.
Fish Shellfish Immunol. 2012 Jan;32(1):132-40. doi: 10.1016/j.fsi.2011.11.001. Epub 2011 Nov 9.
C-type lectins play crucial roles in innate immunity to recognize and eliminate pathogens efficiently. In the present study, two C-type lectins from shrimp Litopenaeus vannamei (designated as LvLectin-1 and LvLectin-2) were identified, and their expression patterns, both in tissues and toward pathogen stimulation, were then characterized. The full-length cDNA of LvLectin-1 and LvLectin-2 was 567 and 625 bp, containing an open reading frame (ORF) of 471 and 489 bp, respectively, and deduced amino acid sequences showed high similarity to other members of C-type lectin superfamily. Both two C-type lectins encoded a single carbohydrate-recognition domain (CRD). The motif of Ca(2+) binding site 2 in CRD, which determined carbohydrate-binding specificity, was QPN (Gln(122)-Pro(123)-Asn(124)) in LvLectin-1, but QPD (Gln(128)-Pro(129)-Asp(130)) in LvLectin-2. Two C-type lectins exhibited similar tissue expression pattern, for their mRNA were both constitutively expressed in all tested tissues, including hepatopancreas, muscle, gill, hemocytes, gonad and heart, furthermore they were both mostly expressed in hepatopancreas, though the expression level of LvLectin-2 was much higher than LvLectin-1. The expression level of two C-type lectins mRNA in hemocytes varied greatly after the challenge of Listonella anguillarum or WSSV. After L. anguillarum challenge, the expression of both C-type lectins were significantly (P<0.01) up-regulated compared with blank group, and LvLectin-1 exhibited higher level than LvLectin-2; while after the stimulation of WSSV, the expression of LvLectin-2 was significantly up-regulated at 6 h (P<0.01) and 12 h (P<0.05), but the expression level of LvLectin-1 down-regulated significantly (P<0.01) to 0.4-fold at 6 and 12 h post-stimulation. The results indicated that the two C-type lectins might be involved in immune response toward pathogen infection, and they might perform different recognition specificity toward bacteria or virus.
C 型凝集素在先天免疫中发挥着至关重要的作用，能够有效地识别和清除病原体。本研究从凡纳滨对虾（Litopenaeus vannamei）中鉴定了两种 C 型凝集素（命名为 LvLectin-1 和 LvLectin-2），并对其组织表达模式以及对病原体刺激的反应进行了表征。LvLectin-1 和 LvLectin-2 的全长 cDNA 分别为 567 和 625 bp，包含一个 471 和 489 bp 的开放阅读框（ORF），推导的氨基酸序列与其他 C 型凝集素超家族成员具有高度相似性。两种 C 型凝集素均编码一个单一的碳水化合物识别结构域（CRD）。CRD 中 Ca(2+)结合位点 2 的基序决定了碳水化合物结合特异性，在 LvLectin-1 中为 QPN（Gln(122)-Pro(123)-Asn(124))，而在 LvLectin-2 中为 QPD（Gln(128)-Pro(129)-Asp(130)）。两种 C 型凝集素表现出相似的组织表达模式，其 mRNA 在所有检测的组织中均持续表达，包括肝胰腺、肌肉、鳃、血细胞、性腺和心脏，此外，它们在肝胰腺中的表达水平最高，尽管 LvLectin-2 的表达水平远高于 LvLectin-1。血细胞中两种 C 型凝集素 mRNA 的表达水平在受到鳗弧菌或 WSSV 攻击后差异很大。在鳗弧菌刺激后，与空白组相比，两种 C 型凝集素的表达均显著上调（P<0.01），且 LvLectin-1 的表达水平高于 LvLectin-2；而在受到 WSSV 刺激后，LvLectin-2 的表达在 6 h（P<0.01）和 12 h（P<0.05）时显著上调，但 LvLectin-1 的表达水平在刺激后 6 和 12 h 时显著下调（P<0.01）至 0.4 倍。结果表明，这两种 C 型凝集素可能参与了对病原体感染的免疫反应，并且它们可能对细菌或病毒具有不同的识别特异性。
