A new fibrinogen-related protein from Argopecten irradians (AiFREP-2) with broad recognition spectrum and bacteria agglutination activity

作者：Yang Chuanyan; Wang Leilei; Zhang Huan; Wang Lingling; Huang Mengmeng; Sun Zhibin; Sun Ying; Song Linsheng^*

来源：Fish & Shellfish Immunology, 2014, 38(1): 221-229.

DOI：10.1016/j.fsi.2014.03.025

• Argopecten irradians
• FREP
• Innate immunity
• Pattern recognition receptor
• Agglutination activity

Fibrinogen-related proteins (FREPs) are a kind of pattern recognition receptors (PRRs) containing fibrinogen-like (FBG) domains, and they play curial roles in the innate immune response. In the present study, a new FREP protein was identified from bay scallop Argopecten irradians (designated as AiFREP-2). The full-length cDNA of AiFREP-2 was of 1299 bp with an open reading frame of 762 bp encoding a polypeptide of 253 amino acids, including a signal sequence and an FBG domain. The FBG domain in AiFREP-2 was highly similar to those of ficolins, tenascins and other FREPs. The mRNA expression of AiFREP-2 could be detected in all the examined tissues with the highest level in gill. The mRNA expression of AiFREP-2 in hemocytes was significantly up-regulated post the stimulation of lipopolysaccharide (LP5), peptidoglycan (PGN) and beta-glucan (GLU) (P < 0.01). The recombinant AiFREP-2 (rAiFREP-2) could bind not only different PAMP ligands including LPS, PGN and GLU, but also various microbes including Gram-negative bacteria (Vibrio anguillarum), Gram-positive bacteria (Staphylococcus aureus) and fungus (Pichia pastoris and Yarrowia lipolytica). Additionally, rAiFREP-2 exhibited obvious agglutination activity towards Gram-negative bacteria V. anguillarum and Gram positive bacteria S. aureus. The results indicated that AiFREP-2 was involved in the immune response against Gramnegative bacteria, Gram-positive bacteria and fungus as a PRR in bay scallop, and the information was helpful to understand the innate immune defense mechanisms of mollusks.

• 出版日期2014-5
• 单位中国科学院大学; 中国科学院海洋研究所