Predicting MHC-Ⅱ Binding Affinity Using DE And PSSM

T-cell epitope was referred as antigenic determinant. It can be recognized by specificmolecule and play an important role in response. according to different sources T-cellepitopes can be divided into two classes endogenous antigen and exogenous antigen,generation process of exogenous antigen: external antigen combines lysosome as internallysosome, it was dilacerated into pieces by the cathepsin and catalase then integrated withmajor histocompatibility complex (MHC) to MHC Ⅱcomplex and deliveried to the surfaceof antigen presenting cells (APC), recognized by T cell receptor (TCR), at last activatedassistant T-cell to response. Generation process of endogenous antigen: the antigen whichcame from cell will be decomposed into many small pieces by proteosome, these small piecescan combine with MHC-I into MHC complex and deliveried to antigen presenting cell (APC)recognized by T cell antigen receptor (TCR) and then activated T cell response. The abovedescription shows that the generation of T-cell epitope depends largely on how the antigenwas processed and presented, the combination of the MHC molecule and antigen was crucialin the processing and presenting process for antigen. Therefore, in-depth research to oneMHC molecule in conjunction with which kind of antigen peptide, Discovery the bindingcapacity between MHC molecule and antigen peptide can help us to know the immuneprocess more and develop vaccines. In this article, the study object was MHC-II molecules.The analysis method was the combination of Differential Evolution (DE) andposition-specific scoring matrix (PSSM). By means of building ligand model for17kinds ofMHC-Ⅱ, training and analysis the data, comparing it with other methods, the method in thispaper performed better.