ABSTRACT
<p><b>OBJECTIVE</b>To obtain peptide mimicking epitopes of Schistosoma japonicum (S. japonicum) through screening of a phage peptide library and to test their potential for induction of protection.</p><p><b>METHODS</b>S. japonicum infected sera from Microtus fortis (IMFS) and normal sera from Microtus fortis (NMFS) were used respectively to screen a 12-mers random peptide library by testing the reactivity of anti-S. japonicum serum with the phagotopes. After three rounds of biopanning, the pooled phages were used to immunize mice, after which challenge infection was performed.</p><p><b>RESULTS</b>Of 12 randomly picked clones, 10 clones selected using IMFS and 7 clones selected using NMFS were shown to be antigenic. Significant reduction in adult worms (22.6%) and a high reduction (68.9%) in liver eggs were achieved following immunization with phages screened with IMFS. However, no protection was elicited by those selected with NMFS.</p><p><b>CONCLUSION</b>The results show that the phagotopes are both antigenic and immunogenic, suggesting a potential use of phage displayed peptide as novel vaccines against S. japonicum.</p>
Subject(s)
Animals , Arvicolinae , Parasitology , Epitopes , Helminth Proteins , Allergy and Immunology , Peptide Library , Schistosoma japonicum , Allergy and Immunology , Schistosomiasis japonica , Vaccines , Allergy and ImmunologyABSTRACT
Objective To obtain the short peptides mimicking antigenic epitopes of Trichinella spiralis ( T/^ ), and explore their cross protective immunity against Schistosoma japonicum ( S^j. ) in mice. Methods IgG antibodies were purified from sera of mice infected with T/^ . The purified IgG was used to immunoscreen a phage random peptide library of 7 amino\|acid residues displayed as a fusion to protein of filamentous phage. Positive clones were obtained by affinity selection, the reactivity of each clone binding to specific IgG was detected by ELISA. Kunming mice were immunized subcutaneously three times with mixed phage clones. The mice were sacrificed 45 days after challenge. The worms and the liver eggs were counted. Results After three rounds of panning, the relevant phages had been enriched approximately 150 times in production as compared to those from the first round. Of 24 phage clones randomly selected from the third round biopanning, 21 clones were shown to actually bind to the specific IgG. As compared with the control group, the worm and the liver egg reduction rates in vaccination group were 42^8% and 66^3% ( P
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ObjectiveTo explore the poss ib le mechanisms of killing effects of serum from Microtus fortis to Schistosoma japonicum schisto somula in vitro. MethodsSerum was separated into protein fraction and
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Objective To screen the 12 mers-phage random peptide library using the serum from the new model rabbit and to identify the immuno-protection of the positive phages. The new model infected with Schistosoma japonicum was proved that has a high protection against the challenge infection. Methods After being absorbed by E.coli antibody, the serum of the new model rabbit was used to screen the peptide library. Through three rounds of biopaning and enriching, lots of positive phages were obtained and their antigenic ability was tested. Every mouse was immunized by subcutaneously injecting 1?10 14 pfu positive phages from the new model rabbit serum respectively at 0-2-4 th week. After 4 weeks of the last immunization, the challenge infection was performed. At the same time, several control groups including the group immunized with the phages from the rabbit serum of the normal model infected with Schistosoma japonicum, the group immunized with the original 12 mers-phage random peptide library and the control group of challenge infection were arranged. Results ①The positive clones of phage(1?10 14) from the new model rabbit serum were strongly recognized by the rabbit serum of the new model, weakly recognized by the rabbit serum of the normal model infected with Schistosoma japonicum,but not recognized by the serum of healthy rabbit. ②The reduction rate of adult worms and liver eggs induced by phages screened with the rabbit serum of the new model group and the nomal model group and that induced by the original peptide library were respectively 27 2% and 38 8 %, 17 8% and 35 0%, 4 5% and 6 0% Conclusion The new model group obtained a higher reduction rate of adult worms than the nomal model group (P
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0.05). Conclusion pcDNA3.1/SjTs-1 induced the mucosal and systemic immune response and partial protection against the challenge of S.japonicum by the intranasal vaccinations of mice.
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0. 05) and the specificity is higher than that of the SEA-ELISA (P