| Schistosomiasis is a serious threat to the public health, social and economic development. Although great achievements on prevention and treatment of Schistosomiasis have been obtained in our country, Schistosomiasis is still epidemic seriously in some areas. The effect of molluscicidal is diffcult to protract and steady, but can bring about the ecosystem pollution of the environment. Moreover, some schistosome strains of praziquantel-resistant to the drug have been observed recently in several countries. As the complement to chemotherapy and other approaches, the development of anti-Schistosomiasis vaccines is necessary to effectively combat the disease. So far, the current status in the development of Schistosoma japonicum vaccines will then be discussed. New approaches that adjuvants and the understanding of immune mechanism may improve on the efficacy of available vaccines.In this study, the recombinant proteins LHD-Sj23and SjTSP2were purified using GST-Binding-resin affinity chromatography. BALB/c mice as animal model were immunized with purifeid LHD-rSj23and rSjTsp2emulsified with FA or ISA206or ISA70M adjuvant for3times, then challenged with40±2cercariae,and6weeks later, the adult worms were recovered by perfusion from the mice’s hepatic portal vein. Total adult worm burdens and liver eggs were counted. The level of protection of vaccinated group was calculated as a percentage based on the reduction in worm burdens or liver eggs per female worm was also calculated according to the control group. In animal experiments, the recombinant antigen LHD-Sj23could induce a certain effect on protecting from infecting with Schistosoma japonicum in BALB/c mice. The protections against Schistosoma japonicumin generated by the antigen rSjTSP2were related with the type of adjuvants in BALB/c mice. ISA206adjuvant group which received the highest protective effect, followed by Freund’s adjuvant group, but ISA70M adjuvant without protecton. We are still in the dark when it comes to the desired protective mechanisms required to engineer an efficacious recombinant vaccine for schistosomiasis. To study the mechanisms preliminarily, this experiment detected the cellular and humoral response which generated by the antigens immunization by flow cytometry (FCM) and enzyme-linked immune assay (ELISA). One week after the time when the mice were injected three times, the lymphocyte subsets CD4+,CD8+cells and the intracellular cytokines IL2, IL4, IL10, IFNy, IL12were determined when the mice were injected three times. The mice serum samples were collected at week1before immunization, at week6(one week after the last injection) and at week13(the mice were sacrificed for6weeks). The level of specific IgG and subtypes IgG1, IgG2a, IgG2b, IgG3,and specific IgE, IgA, IgM in the serum against LHD-rSj23and rSjTsp2was determined by ELISA. Compared with the control group, the changes of the CD4+,CD8+values, the calculated ratio of CD4+/CD8+and the changes in the values of IL2, IL4, IL10, IFNy, IL12indicated that the mice in experimental groups induced a mixed Th1/Th2immune response and Thl appears to be the dominant of the two. The ELISA results showed that there were a strong humoral response in the experimental groups mice. The antibody type against the recombinant antigens LHD-Sj23and SjTSP2in the serum was mainly IgG and subtype IgGl, IgG2a, IgG2b, IgG3.This experiment illustrated the immune protective effect created by the antigens LHD-Sj23and SjTSP2were the result of both cellular and humoral response. This paper could provide a sense of reference for the development of a successful anti-schistosomiasis vaccine. |
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