Construction Of Recombinant Plasmid Co-encoding SjFer And GM-CSF And Its Elicited Immunoprotection In Mice

Schistosomasis japonicum is a kind of serious, worldwide zoonoses. The schistosomasisvaccine researches is an important field of probing control of schistosomsis. For decades'effort, the great achievement in Schistosoma japonicum(Sj.) vaccine research had been made.But the immunoprotection of these studied vaccines was low to control the spread andpathogenesis of S.j. It is nessesary to study how to increase the immunoprotection of thesevaccines. The aim of this study was to test immunoprotection elicited by EukaryoticExpression Vector co-encoding SjFerritin and GM-CSF against Schistosoma japonicum(Sj)inmice to make out improvement of GM-CSF as adjuvant.The special primers were designed according to the sequence of SjFer gene in GeneBank.SjFer was amplified using Sj. adult worm cDNA library as temple. Reconstructed plasmidswere constructed by routine methods. Eighty-five female mice were randomly divided into 5groups, 17 each group. Group A. B as control were immunized with 50μl normal salt waterand 50μg pcDNA3.0 respectively and Groups C,D,E were immunized with 50μgpcDNA3.0/GM-CSF,50μg pcDNA3.0/SjFer and 50μg pcDNA3.0/SjFer-GM-CSF per mouseand times respectively in 0-2-4th week. Sera were collected before immunization andchallenge infection. Levels of specific antibody were detected by ELISA. Lymph-spleencytesof mice were collected two weeks after final immunization. Proliferation activity ofLymph-spleencytes proliferation was detected by MTT assay. The mice were challenged with40±1 S. j cercariae per mouse 2 weeks after the final vaccination. Forty-five days later, micewere killed and perfused, and the adult worms, eggs were counted. Results showed:pcDNA3.0/SjFer,pcDNA3.0/GM-CSF and pcDNA3.0/SjFer-GM-CSF could express inmuscle cells of mice. The sera IgG level increased significantly in group D, E. And that ingroup E were higher than in group D. The proliferation activity of spleen T lymphocytesdetected by MTT assay increased significantly in group D and E atter induced by ConA orrecombinant proteins rSjFer before challenge infection, and had significant differencecompared with A, B, C groups. That in group E were higher than in group D. The adult wormreduction rate of group D and E was 36.27％and 39.22％. The egg reduction rate of themwas 36.10％and 49.04％.In conclusion, GM-CSF stronged humoral and cellular immunity and immunoprotectionelicited by eucaryotic expression vector encoding SjFer in mice.