| Vaccine is an efficient measure to prevent and control infectious disease. Usingschistosomasis japonicum vaccine for prophylaxis as a relatively cheap and long-effectivemeasure, is a goal for people to pursue. The study of schistosomasis japonicum vaccineundergoes three stages: inactivated vaccines, attenuated live vaccines, subunit vaccines andgenetic engineering vaccines. DNA vaccine is an important field of schistosomasis japonicumvaccine research. Because of low immunoprotection of studied candidate-molecule vaccines,it is necessary to study how to improve their immune efficacy and find new candidatemolecule vaccines with high immune efficacy against challenge infection.1. To detect the protection in mice induced by DNA vaccine encoding SjIR3 against thechallenge of Sj in this research, SjIR3 was amplified by PCR from adult worm cDNA libraryand the recombinant plasmid SjIR3/pC was constructed by routine methods. Fifty-four femalemice were randomly divided into 3 groups (each 18 immunized with normal saline (100μl),pcDNA3.0 and SjIR3/pC (50μg) respectively. The all groups immunized three times withinterval of two weeks. The mice were infected by (40±1) Sj cercariae per mouse 2w after finalimmunization. Forty-five days later, mice were sacrificed and perfused, the adult worms andeggs were counted. Sera were collected before the every immunization and challengeinfection.The serum 1gG were detected by ELISA, and the spleenocytes of mice werecollected before challenge infection. The proliferation activity of spleen T lymphocyteinduced by ConA or rSjIR3 was detected by MTT assay. The results of ELISA showed nosignificant change of sera 1gG level group A and B, but considerable increase in experimentalgroup immunized by SjIR3/pC (0.78±0.05). And the proliferation activity of spleen Tlymphoeytes detected by MTT assay increased with induction of ConA or recombinantproteins rSjIR3 after final immunization. The A570 is 0.57±0.02, and 0.684±0.01, respectively,with significant difference compared with two control groups (P＜0.01). The worm reductionrate and the egg reduction rate in experimental group were 29.42％and 36.56％respectively.2.mGM-CSF was amplified by PCR with specific primers. The recombinant plasmidSjIR3-GMCSF/pC and mGM-CSF/pC was constructed by routine methods. Ninety femalemice were randomly divided into 5 groups immunized with normal saline (100μl),pcDNA3.0(50μg), SjIR3/pC(50μg), mGM-CSF/pC(50μg) and SjIR3-GMCSF/pC (50μg)respectively. Protocal of immunization and animal challenge infection experiment was same as the above. The results of ELISA showed the level of 1gG in sera of two control groups hadno changes, and the level of sera 1gG in groups immunized by SjIR3/pC or SjIR3-GMCSF/pCincreased (0.78±0.04,0.91±0.03) and had significant difference compared with that in controlgroups (P＜0.01). And the proliferation activity of spleen T lymphocytes detected by MTTassay increased after induction of ConA or recombinant proteins rSjIR3. A570 is 0.56±0.07 and0.68±0.05, 0.56±0.07 and 0.77±0.04, respectively, with significant difference compared withthree control groups (P＜0.01). The worm reduction rate and the egg reduction rate in groupsimmunized by SjIR3/pC or SjIR3-GMCSF/pC were 39.81％and 34.75％, 33.96％and 28.43％,respectively. In conclusion, DNA vaccine encoding SjIR3 induced humoral and cell-mediatedimmune response and partial immune protection against the challenge infection in mice.mGM-CSF improved the humoral and cell-mediated immune response induced by DNAvaccine encoding SjIR3 and immunoprection against challenge infection in mice. It was worthfurther studying induction of immune response and immunoprotection against challengeinfection in livestock. This data also showed SjIR3 DNA vaccine become possible asingredient of Schistosomasis "cocktail vaccine".
|
PDF Full Text Request