Identification of Immunodominant Th1-type T cell Epitopes from <italic>Schistosoma japonicum</italic> 28 kDa Glutathione-S-transferase, a Vaccine Candidate

Abstract

Th1-type cytokines produced by the stimulation of Th1-type epitopes derived from defined schistosome-associated antigens are correlated with the development of resistance to the parasite infection. Schistosoma mansoni 28 kDa glutathione-S-transferase (Sm28GST), a major detoxification enzyme, has been recognized as a vaccine candidate and a phase II clinical trial has been carried out. Sheep immunized with recombinant Schistosoma japonicum 28GST (Sj28GST) have shown immune protection against the parasite infection. In the present study, six candidate peptides (P1, P2, P3, P4, P7 and P8) from Sj28GST were predicted, using software, to be T cell epitopes, and peptides P5 and P6 were designed by extending five amino acids at the N-terminal and C-terminal of P1, respectively. The peptide 190-211 aa in Sj28GST corresponding to the Th1-type epitope (190-211 aa) identified from Sm28GST was selected and named P9. The nine candidate peptides were synthesized or produced as the fusion protein with thioredoxin in the pET32c(+)/BL21(DE3) system. Their capacity to induce a Th1-type response in vitro was measured using lymphocyte proliferation, cytokine detection experiments and flow cytometry. The results showed that P6 (73-86 aa) generated the strongest stimulation effect on T cells among the nine candidate peptides, and drove the highest level of IFN-gamma and IL-2. Therefore, P6 is a functional Th1-type T cell epitope that is different from that in Sm28GST, and will be useful for the development of effective vaccines which can trigger acquired immunity against S. japonicum. Moreover, our strategy of identifying the Th1-type epitope by a combination of software prediction and experimental confirmation provides a convenient and cost-saving alternative approach to previous methods.

Molecular cloning, expression, IgE binding activities and in silico epitope prediction of Per a 9 allergens of the American cockroach

“…Although this method decreases the possibility of missed epitopes, it needs to synthesize lots of peptides and is very costly and time-consuming (49). In silico prediction has already become a familiar and useful tool for selecting epitopes from immunologically relevant proteins, which can save the expense of synthetic peptides and the working time (50). A previous study demonstrated that the use of the bioinformatics approach to predict B cell epitopes correlated well with the experimental approach (51).…”

In SilicoPrediction of T and B Cell Epitopes of Der f 25 inDermatophagoides farinae

“…In silico prediction has already become a familiar and useful tool for selecting epitopes from immunological relevant proteins, which can save the expense of synthetic peptides and the working time [44]. Recently, many algorithms have been developed to predict B cell epitopes on a protein sequence based on propensity values of amino acid properties of hydrophilicity, antigenicity, segmental mobility, flexibility, and accessibility [45].…”

CD4+CD25+ Treg induction by an HSP60‐derived peptide SJMHE1 from Schistosoma japonicum is TLR2 dependent

“…Epitope prediction was carried out as described previously [52][53][54]. Briefly, the amino acid sequences of SjHSP60 (GenBank accession no.…”