Identification of linear B-cell epitopes within Tarp of Chlamydia trachomatis.
Chlamydia trachomatis is one of the most prevalent sexually transmitted pathogens. There is currently no commercially available vaccine against C. trachomatis. Chlamydial translocated actin-recruiting phosphoprotein (Tarp) can induce cellular and humoral immune responses in murine models and has been regarded as a potential vaccine candidate. In this report, the amino acid sequence of Tarp was analyzed using computer-assisted techniques to scan B-cell epitopes, and six 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. Sera from mice immunized with these potential immunodominant peptides was analyzed by ELISA, which showed that epitope 152-170 elicited serum immunoglobulin G (IgG) response and epitope 171-186 elicited both serum IgG and mucosal secretory immunoglobulin A response. The response of immune sera of epitope 171-186 to endogenous Tarp antigen obtained from the Hela229 cells infected with C. trachomatis was confirmed by Western blot and indirect fluorescence assay. In addition, binding of the antibodies against epitope 171-186 to endogenous Tarp was further confirmed by competitive ELISA. Our results demonstrated that the putative epitope (aa171-186) was an immunodominant B-cell epitope of Tarp. If proven protective and safe, this epitope, in combination with other well-documented epitopes, might be included into a candidate epitope-based vaccine against C. trachomatis.
Department of Microbiology and Immunology, Wenzhou Medical University, Wenzhou, 325000, China.
Shanli
S
Zhu
Yan
Y
Feng
Jun
J
Chen
Xiaoyun
X
Lin
Xiangyang
X
Xue
Shao
S
Chen
Xiaozhi
X
Zhong
WenShu
W
Li
Lifang
L
Zhang
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000737:chemistry* / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry*; D002692:Chlamydia trachomatis / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D000939:Epitopes; D007074:Immunoglobulin G
B-cell epitope; Chlamydia trachomatis; immune response; translocated actin-recruiting phosphoprotein (Tarp)