The Prediction And Identification Of T Helper Cell Epitopes In Tegument Molecule Of Schistosomulum Of Schistosoma Japonicum

Schistosomiasis, as a parasitic disease of zoonotic, seriously affected the socio-economic sustainable development including agriculture and animal husbandry. The application of schistosome vaccine in humans and animals to block the transmission of schistosomiasis is recognized as the long-term effective control strategy. Research on security and efficient schistosomiasis vaccine has been difficult to have great progress, due to challenge of identification of protective antigen. One of the important breakthrough methods of vaccine development against schistosomiasisi is to emulate the high protective immune mechanisms induced by radiation-attenuated (RA) cercariae vaccine, mediated by Th cell in targeted schistosomulum. For theoretical guidance to reverse vaccine, our research predict candidated T helper cell epitopes in the tegument molecule of schistosomulum of Schistosoma japonicum identified from transcriptomic by using the online server resources, meanwhile, to validate the predicted Th cell antigens by lymphocyte proliferation assay, provide basis for further experimental identification of predicted Th cell antigens from the tegument molecule of schistosomulum.373 tegument sequences of schistosomulum japonicum in 18,579 hepatic phase of schistosomulum EST sequence were obtained from annotation data from both originals and the related sequence information of Chinese National Human Genome (South) Center. After its signal peptide and transmembrane structure were predicted, the 14 sequences were screened out by using prediction software of protein secondary structure based on artificial neutral network, HMM and weight matrix.The peptides of the above sequences binding to the MHC II molecules of human and mice were predicted using many severs based on binding motif, matrix, artificial natural network; The binding of above peptides to MHC II molecules was further optimized using docking simulation sever of receptor and ligand based on molecular dynamic algorithm. 5 promiscous candidated pentadeca-peptides binding to at least one MHC II molecules of mice were obtained by epitope prediction:NQFIRNLTLKIVLPE [resource sequence:AY813997; similar to dolichyl-diphosphooligosaccharide—protein glycosyl transferase]; SSTSQDFPGVCQLCV[resource sequence :AY815893; similar to Prosaposin]; SSLVISYSTVDRLVC[resource sequence :AY815893; similar to Prosaposin]; SRNLTVLRTNVALRL[resource sequence:AY811606; similar to NM₀69913 protein disulphide isomerase-related protein like in Caenorhabditis elegans] TVKFDKTVTCGGAYI[resource sequence:AAC00515; calreticulin family].Proliferation of spleen lymphocyte in mice vaccinated with candidated epitopes synthesized artificially (coupled with the poly-lysine skeleton) was validated using modified MTT method. Peptide SSLVISYSTVDRLVC [resource sequence: AY815893] was confirmed as the potential Th cell epitope of tegument molecule.In this study, Th cell epitopes in tegument Molecule of schistosomulum of Schistosoma japonicum were indentified by combination with the immunoinformatics theoretical prediction and in vitro detection technology, the result provide foundation for further study on screening out the new candidate protective T-cell epitopes against Schistosoma japonicum.