Purification And Characterization Two New Lectin From The Hemolymph Of The Shrimp Fenneropenaeus Chinensis And Litopenaeus Vannamei

Shrimp is a very important commercial animal on Chinese mariculture, however,the shrimp industry has always been affected by infectious diseases, mainly ofbacterial and viral etiology, causing great loss of production. In order to promote theresearch on shrimp disease defense and genetic breeding, the knowledges on theimmunity mechanisms of shrimp become an urgent and basic need. The immunityindexes of cellular and humoral immune system were investigated to find the mosteffective one for the selection of immunostimulants .To explain the causes of theimmune response about the shrimp, several methods were tried to purify thelectin-one of the important pattern recognition protein (PRPs) in shrimp.In this study a natural lectin from the serum of the shrimp Fenneropenaeuschinensis was purified by three different affinity chromatography usingN-acetylglucosamine-coupled agarose, Fetuin-coupled agarose and Bovine mucin(BSM)-coupled Sepharose 4B.This lectin was named FCL-1 and its inactive form hada molecular mass estimate of 168 kDa .We also purified this lectin by fresh red bloodcells (RBC) from mouse. In hemagglutinating activity (HA) inhibition assaysperformed with several carbohydrates and glycoproteins FCL-1 showed a distinctspecificity for acetyl group in carbohydrates and Sia-group in sialoglycoconjugates.It's activity specifically dependent on Ca²⁺ and reversibly sensitive to EDTA. The HAactivity of FCL-1 was also susceptible to inhibition by temperature and pH. It'sactivity would lost when the temperature was over 75℃. And the HA activity ofFCL-1 would be inhibited when the pH was under 4 or above 11. It could cause slightagglutination of cell from the stomach cancer and liver cancer. And the lectin FCL-1could have a strong interact with bacterias that were closely related to the shrimp orfish disease. Peptide mass fingerprinting attested this lectin was a new protein inshrimp Fenneropenaeus chinensis.A natural lectin LVL from the serum of the shrimp Litopenaeus vannamei waspurified by a single-step affinity chromatography using Fetuin–coupled agarose. Thepurified serum lectin (LVL) showed a strong affinity for human A/B/O erythrocytes(RBC), chicken RBC and its hemagglutinating (HA) activity was specificallydependent on Ca2+. LVL in active form has a molecular mass estimate of 172 kDa andis composed of two non-identicalsubunits (32 and 38 kDa) cross-linked by interchaindisulfide bonds. Significant VLV activity was observed between pH 7-11. InHA-inhibition assays performed with several carbohydrates and glycoproteins, VLVshowed a distinct and unique specificity for GalNAc/GluNAc and glycoproteins richin Sialic Acid. The HA activity of FCL-1 was also susceptible to inhibition bytemperature and pH. It's activity would lost when the temperature was over 75℃. Andthe HA activity of FCL-1 would be inhibited when the pH was under 4 or above 11. Itcould cause slight agglutination of cell from the stomach cancer and liver cancer. TheLitopenaeus vannamei lectin LVL was also recognize lipopolysaccharides fromdiverse bacteria which caused shrimp and fish disease.