FENG Yan,ZHU Shanli,LIN Xiaoyun, et al. Prediction and identification of linear B-cell epitopes within Tarp of Chlamydia trachomatis[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2014, 44(6): 395-400.
Abstract：Objective: To predict and identify the B-cell epitope of Chlamydia trachomatis Tarp. Methods: The amino acid sequence of Tarp was analyzed using computer-assisted techniques to scan B-cell epitopes, and 6 possible linear B-cell epitopes peptides (aa80-95, aa107-123, aa152-170, aa171-186, aa239-253 and aa497-513) with high predicted antigenicity and high conservation were investigated. After coupling to KLH, the synthetic peptides were emulsifield with Freund’s adjuvant. Then, BALB/c mice were randomly assigned to receive (subcutaneous injection) peptides-KLH, KLH or PBS (n=3, 100 μg/time/mouse), respectively, and the same immunization schedule was repeated third times at a 2-week interval. ELISA was used to detect the IgG and subtypes IgG1, IgG2a in the serum as well as the sIgA in the vaginal secretions. Furthermore, the specific binding of anti-sera produced by epitopes immunization to natural Tarp antigen was detected with indirect immunofluorescence assay (IFA), immunoprecipitated and Western blot analysis, respectively. Results: The epitope peptide F4 (aa171-186) was able to induce significant Tarp specific antibody IgG in serum and sIgA in vaginal wash as compared with KLH or PBS (1:100) (P<0.05), and the major IgG antibody subtype was IgG1. Western blot and IFA results confirmed that specific antibodies were induced by epitope aa171-186 recognized natural Tarp antigen. Conclusion: Our results demonstrated that the predictive epitopes (aa171-186) are immunodominant B-cell epitope of Tarp, and if proven protective and safe, in conjunction with others well-documented epitopes, they may be included into a candidate epitope-based vaccine.
