Immuno-Protection Of SJIR-2 DNA Vaccine With Microspheres Adjuvant In Mice Challenged With Schistosoma Japonicum

Objective Schistosomiasis japonicum is seriously damage to human health, to research effective vaccine to prevent and control this disease has become a hotspot in the field of this disease.This study intends to make schistosoma japonicum insulin receptor-2 nanometer microspheres nucleic acid vaccine (SJIR-2) and research the immuno-protection of this vaccine against Schistosoma japonicum infection in mice,so as to provide an effective new way for the prevention and control of schistosomiasis japonicum Methods to collect adult schistosomas from rabbit body which was infected schistosoma japonicum cercaria 45 days ago, the total RNA of Schistosomiasis japonica was extracted by Trizol and then translate RNA into cDNA with retrovirus kit,PCR was used to amplification SJIR-2 gene with the cDNA as template,then construct eukaryotic expression plasmid pEGFP-SJIR-2, identified by double digestion,PCR and sequenced delivery, the recombinant plasmid was transfected into 293 T cells and Westernblot was used to identify its expression in eukaryotic cells. The recombinant plasmid pEGFP-SJIR-2 was extracted and was encapsulated into PLGA nanometer microspheres which were modified by CHS for the preparation of SJIR-2 nanometer microspheres vaccine.40 female BALB/c mice were randomly divided into 4 groups (n=10), each group of mice were injected with PBS, empty pEGFP plasmid, CHS-PLGA nanometer microspheres and CHS-PLGA-pEGFP-SJIR-2 nanometer microspheres 100 μg, respectively. Two weeks after the last immunization, each mouse was infected by cercaria of S.japonicum, sera of mice in each group were collected before each immunization and challenge infection. ELIS A was used to detect the change of IgG in each group of mice sera.42 days later, all mice were sacrificed, the adult worms and eggs were collected and counted, the worm and egg reduction rates were calculated as well. Results The total RNA of Schistosomiasis japonica was extracted and translated into cDNA successfully, SJIR-2 gene was amplificated successfully and the recombinant plasmid pEGFP-SJIR-2 was constucted too, both the results of double digestion and PCR identification were correct. The recombinant plasmid was transfected into 293 T cells successfully and Westernblot results showed that the recombinant proteins can be expressed in eukaryotic cells. There was significant difference in the numbers of worm and egg between CHS-PLGA-pEGFP-S JIR-2 group and PBS group (P<0.01), the worm and egg reduction rates in CHS-PLGA-pEGFP-SJIR-2 group were 37.36% and 46.82% respectively, the IgG leveals in mice sera of CHS-PLGA-pEGFP-SJIR-2 group were remarkably higher (P<0.01) compared with PBS group, on the contrary, there were no significant difference between both pEGFP plasmid group and CHS-PLGA group in the numbers of worm and egg compared with PBS group. Conclusion SJIR-2 nanometer microspheres nucleic acid vaccine has some immuno-protection against Schistosoma japonicum infection in BALB/c mice, while it is worth further studying for it’s potential value to be a candidate antigen molecule of Schistosoma japonicum vaccine.