Study of opsonin-like molecule from coelomic fluid of Strongylocentrotus intermedius

In order to study the immune mechanism of coelomic fluid of Strongylocentrotus intermedius,we researched the phagocytosis activity in different media and different treatments of yeast cell.Then we analysed the non-cell coelomic fluid and ingredient which was isolated from regulating yeast cells and non-regulating yeast cells with SDS-PAGE,and the non-cell coelomic fluid was dialysed,SephadexG-200 gel chromatography,and SDS-PAGE;In isotonic buffer and cell-free coelomic fluid by yeast cell adsorption,we determined the phagocytosis effected by opsonin-like molecule of different concentration and different time.The result showed that isotonic buffer,cell-free coelomic fluid by yeast cell adsorption and non-cell coelomic fluid all can regulate phagocytosis,and the ratio was 1.00:1.11:1.94,and the phagocytosis rate of regulating yeast cells was 1.61 times of non-regulating yeast cells in isotonic buffer;There was a new opsonin-like molecular band from ingredient which was isolated from regulating yeast cells,and the molecular weight is 250.62 ku.We also found the molecular weight is 250.62 ku after dialysis,SephadexG-200 gel chromatography;In tested concentration range,the greater the opsonin-like concentration,the higher the phagocytosis and 5.0 and 10.0 μg/mL groups were higher than control group in each test time.In isotonic buffer,10.0 and 5.0 μg/mL groups had very significant difference(P<0.01)compared to control group in 30 min after reaction.In cell-free coelomic fluid by yeast cell adsorption,10.0 μg/mL group had significant difference compared to control group(P<0.05)in 30 min after reaction.These results indicate that there is a kind of new opsonin-like molecule in coelomic fluid of S.intermedius and the molecular weight is 250.62 ku which can promote phagocytosis.