Studies On Biological Properties Of The Lectin In Serum Of Eriocheir Sinensis

Methods of microagglutination assay, orthogonal expetimental design, SDS-PAGE, dot-ELISA were used for biological characterization of lectin in serum of river crab, Eriocheir sinensis.A microagglutination assay was carried out on serum lectin activity of crab. The results of showed that the serum could agglutinate ervthrocytes of chicken, rabbit, culver, mouse, human (A,B,O type), but not these of crucian and turtle. It could also agglutinate bacteria such as Sarcina and Aeromonas hydrophila (J-l) excluding E.coli,parvobacteriaî–ºaphylococcus aureus, Vibrio mimicus H7 and Pseudomonas 1.2. Moreover, a significantly higher liter was observed in the microagglutination assay between crab serum and mouse cells or Sarcina than and other kinds of animal erythrocytes or bacteria (p<0.01). The agglutination titers were obviously variable among the individual crabs, but not significantly different between male and female crabs (p>0.05).Presence of a concentration with 0.01M Ca2+or with 0.3M NaCl could not influence the activity of agglutinating mouse cell in crab serum, but with 0.6M NaCl the hemagglutination liter could be decreased. The serum treated by 0.1-0.4M EDTA al pH 5.0 lost ils hemagglulinating aclivity.A 3 X 3 design of orthogonal experimenl was used lo delecl Ihe effecl of ihree kinds of factors on Ihe agglulinaling activity of Ihe crab serum. The resull showed lhal Ihe aclivity didn'l change when waler temperature was altered (p>0.05) and expressed no difference belween groups wilh differenl weighl of crabs. However, injection of Sarcina or saline could induce crab significantly to increase ihe liter of agglulinaling bacteria (p<0.05) . 1~2 d after injecting Ihe agglutination tiler was increased highly and then restored to normal level up lo 12d -14d. In addition, repealed injections of bacteria every 5d-7d would keep liter level of agglulinaling bacteria.Erythrocyte membrane of mouse was used as Ihe affinity malrix for isolation of lectin from crab serum. The Ireated lectin had agglutinating activity againsl mouse erylhrocyle and showed ihree bands aboul 120 100, 117 300 and 114 600 in 10% SDS-PAGE profile.Mice were injected with Isolated lectin. The lectin immunogenity was detected by antibody titers of mice antiserum by hemaggluting inhibition assay and dot-ELISA. The result showed that the crab serum letin could be also an immunogen.