[Prediction of Antigen Epitopes of Associated Protein Rv2004c Latent-infected by Mycobacterium Tuberculosis].

To screen new tuberculosis diagnostic antigens and vaccine candidates,we predicted the epitopes of Mycobacterium tuberculosis latent infection-associated protein Rv2004 cby means of bioinformatics.The homology between Rv2004 cprotein and human protein sequences was analyzed with BLAST method.The second structures,hydrophilicity,antigenicity,flexibility and surface probability of the protein were analyzed to predict B cell epitopes and T cell epitopes by Protean software of DNAStar software package.The Th epitopes were predicted by RANKPEP and SYFPEITHI supermotif method,the CTL epitopes were predicted by means of combination analyses of SYFPEITHI supermotif method,BIMAS quantitative motif method and NetCTL prediction method.The peptide sequences with higher scores were chosen as the candidate epitopes.Blast analysis showed that Rv2004 cprotein had low homology with human protein.This protein had abundant secondary structures through analysis of DNAStar software,the peptide segments with high index of hydrophilicity,antigenicity,surface probability and flexibility were widely distributed and were consistent with segments having beta turn or irregular coil.Ten candidates of B cell epitopes were predicted.The Th epitopes of Rv2004 cprotein were located after the 200 th amino acid.Of 37 Th cell epitopes predicted,there were more epitopes of HLA-DRB1*0401and HLA-DRB1*0701phenotypes,and the MHC restrictive types of some Th cell epitopes exist cross overlap.Of 10 CTL epitopes predicted,there were more number and higher score of HLA-A2 restricted epitopes.Therefore MycobacteriumtuberculosisRv2004 cprotein is a protein antigen with T cell and B cell epitopes,and is expected to be a new target protein candidate for tuberculosis diagnosis and vaccine.