Abstract：
Anti-lipopolysaccharide factors (ALFs) are a family of common innate immune effectors in crustaceans, and they exhibit broad spectrum antimicrobial activity. In this study, we identified and characterized five novel ALF genes (designated as LvALF1-5) from the Pacific white shrimp (Litopenaeus vannamei) to investigate their potential immune functions. The amino acid sequence alignments showed that LvALFs contained two conserved cysteine residues, a hydrophobic N-terminal region, and the conserved signature sequence W(T/K)CPG(S)WT(A). They all shared high similarity with previously reported ALFs and were clearly novel members of the ALF family. The mRNA transcripts of LvALFs were most highly expressed in hemocytes and the hepatopancreas. After shrimp were stimulated with Vibrio parahaemolyticus or white spot syndrome virus, expression of the LvALFs was significantly induced in hemocytes and the hepatopancreas with various expression profiles. Recombinant proteins of LvALFs exhibited potent bacteriostatic activity in vitro. Together, these results suggest that LvALF1-5 participate in the immune response of Pacific white shrimp against invading pathogens.
摘要：
抗脂多糖因子(ALFs)是甲壳类动物中一类常见的固有免疫效应因子,并且它们表现出广谱抗微生物活性。在这项研究中,我们从太平洋白虾（凡纳滨对虾）中鉴定并鉴定了五个新的ALF基因（命名为LvALF1-5），以研究其潜在的免疫功能。氨基酸序列比对显示LvALFs含有两个保守的半胱氨酸残基,疏水性N端区域，和保守签名序列W(T/K)CPG(S)WT(A)。它们都与先前报道的ALF具有高度相似性，并且显然是ALF家族的新成员。LvALF的mRNA转录本在血细胞和肝胰腺中最高表达。对虾用副溶血性弧菌或白斑综合征病毒刺激后，LvALFs的表达在血细胞和具有不同表达谱的肝胰腺中被显著诱导。LvALF的重组蛋白在体外表现出有效的抑菌活性。一起,这些结果表明，LvALF1-5参与了太平洋白对虾对入侵病原体的免疫反应。
