Prokaryotic expression of C-type lectin gene of Litopenaeus vannamei and immunologic activity evaluation of recombinant protein

The studies on innate immune responses of Litopenaeus vannamei C-type lectin, were gained by recombinant C-type lectin protein through expressed in Escherichia coli. We used cell suspension culture to study the effect of C-type lectin on the cellular immune response of Litopenaeus vannamei. The experiment was divided into two groups control group and recombinant protein (1.0 mg/mL). After 0, 3, 6, 9, 12, 24 hours, we harvested the solutions and then assessed parameters respectively. The results showed that SDS-PAGE revealed the molecular weight of LvLec protein was 39KD, which was consistent with the predicted size. Western blot revealed it could bind to anti-His antibody, which proved that C-lectin recombinant protein in Escherichia coli succeeded in expression. For the hemagglutination assay, massive agglutination could be observed after Escherichia coli was incubated with LvLec for 1 h. At the same time, Lvlec protein had a significant effect on haemocyte count, cell viability and phagocytic activity of white shrimp Litopenaeus vannamei(P<0.05). The extracelluar phenoloxidase activity of the Lvlec protein group showed peak changes during 3-12h, at 9h the extracelluar phenoloxidase activity was highest, then recovered to the control level(P<0.05). Therefore, crustacean C-type lectin not only had the function of hemagglutination , but also activated prophenoloxidase activating system, and probably played an important role in immune response.