The Choice Of Multivalent Protein Vaccines Against Schistosomiasis And Research Of Prokaryotic Expression

Schistosome Japanicum is a worldwide problem, which endangers the human healthand even affects the development of civilization severely. The conventional methods ofSchistosome prevention and control have many disadvantages and cannot control thesevere epidemic situation. One of the most effective methods to prevent fromSchistosome Japanicum is to design vaccines. At present protein vaccines and DNAvaccines are two main vaccine types. Although DNA vaccines against schistosomiasiscan provide animals with protection, their safety cannot be confirmed in a short time.However, compared with DNA vaccines, the technic of protein vaccines is more matureand its safety has been verified. As a result, it is more likely that protein vaccines againstschistosomiasis will be in industrialization firstly. There are monovalent protein vaccinesand multivalent protein vaccines, and producing multivalent protein vaccines can reducethe cost and simplify the production process. However, whether the synthesis of fusingprotein will be affected due to its bigger fragment is a problem that need be studied. Forthat, this research has constructed prokaryotic expression systems to do more research ofmonovalent and multivalent protein vaccines against schistosomiasis and has obtainedthe following results:(1) On the basis of Antigens provided by WHO, we made use of the method ofbioinformatics to analyze the hydrophobicity and High-level structure of these antigensand selected out appropriate antigen genes (Sj26, SjGAPDH, Sj26.GAPDH) to do moreresearch.(2) Two monovalent antigen genes, Sj26and SjGAPDH, and one multivalent antigengene Sj26.GAPDH were cloned. Antigen genes were connected with the prokaryoticexpression vector by the molecular method. After the restriction enzyme digestion andsequencing validation, the recombinant vector was constructed successfully. Then we separated and purified these target proteins by nickel ion affinity chromatography column,and found out the best elution condition for these proteins.(3) The quantity of these three antigens was measured by the technique of ELISA. Theanalysis of statistics showed that the quantity of fusing protein expressed by prokaryoticexpression system had no significant difference with the quantity of monovalent proteinexpressed by prokaryotic expression system. Because of it, we could make a decision onthe selection of protein vaccines against schistosomiasis.