Objective: To establish a method based on repetitive protein sequences and linear B cell epitope to predict and screen specific peptides of Plasmodium vivax.
Methods: A P. vivax protein sequence database was reconstructed based on PlasmoDB data, and a customized software for searching of repetitive sequences was used to count the repetition times of each 16 aa peptide in the whole database, and the highly repetitive peptides were chosen to predict the potential linear B cell epitopes. The repetitive peptides with P. vivax specificity were selected as candidate antigen peptides to synthesize and to couple with KLH carrier protein for immunizing BALB/c mice. After the immunization, the antibody titers of the immunized mice were detected.
Results: The repetitive information of 16 aa peptides was analyzed by screening of the total 5 432 peptide sequences in the P. vivax database. A total of 22 peptides were identified as candidate peptides from the top 1 000 repetitive peptides by linear B cell epitope prediction on the BcePred website. Through clustering analysis and similarity comparison, five potential P. vivax specific peptides were selected, synthesized and then coupled with KLH to immunize the mice. The antibody titers of the immunized mice induced by the 5 peptides were all above 1 : 9 000.
Conclusion: The method for predicting and screening of specific peptides of P. vivax based on repetitive protein sequences and linear B cell epitope has been established successfully, and all the 5 peptides obtained by the method can induce the high titer antibody in mice.