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The human papillomavirus (HPV) vaccine has not been widely used in developing countries because of its high cost and multiple subtype restrictions. The present study aimed to develop an ec...

To prepare the dominant multiepitope fusion antigen ROP2-SAG1 (RSmultiepitope) from Toxoplasma gondii in a prokaryotic system, the major immunodominant region (MIR) of the human hepatitis B virus core antigen (HBcAg(MIR)) was used as a delivery vector. The gene encoding the RSmultiepitope was inserted into HBcAg(MIR), and rHBcAg(MIR)-RSmultiepitope was prepared, purified, and administered to BALB/c mice through intradermal injection. An indirect enzyme-linked immunosorbent assay analysis based on a multiepitope peptide facilitated the specific differentiation of sera obtained from mice immunized with the rHBcAg(MIR)-RSmultiepitope protein, and high titers (greater than 1:6,400) of specific anti-RSmultiepitope antibodies were obtained. Immunized splenocytes demonstrated enhanced IFN-γ production. Based on these results, the HBcAg(MIR) vector is easily applied in vitro for targeting the RSmultiepitope and efficiently presents this target epitope for the induction of significant humoral and cellular immune responses. This study offers a novel strategy for the design of a target epitope delivery system for a toxoplasmosis vaccine.

The purpose of this study was to screen and identify the linear B-cell epitopes of Epstein-Barr virus (EBV) latent membrane protein 2 (LMP2). The secondary structure and surface properties of EBV LMP2A protein were analyzed. In combination with hydrophilicity, accessibility, flexibility, and antigenicity analysis, and average antigenicity index (AI) of epitope peptide investigation, three peptides were selected as potential candidates of linear B-cell epitopes. The peptides were 199-209 (RIEDPPFNSLL), 318-322 (TLNLT), and 381-391 (KSLSSTEFIPN). The fragments encoding potential B-cell epitopes were cloned and overexpressed in an E. coli system. The immune sera of these fusion proteins were collected from BALB/c mice by subcutaneously immunizing them three times. Western blotting results showed that these epitope recombinant proteins could be recognized by the serum antibodies against the whole LMP2 from nasopharyngeal carcinoma (NPC). Indirect ELISA measuring individual sera from 196 NPC patients, 44 infectious mononucleosis (IM) patients, 253 healthy adults, and 61 healthy children, indicated that NPC patients had significantly higher reactivity to these epitope-fused proteins compared with IM and healthy individuals (p 0.05). In addition, all the immune sera of peptide-fused proteins responded to native LMP2A antigen obtained from the EBV prototype strain, B95-8 cells. IFA results confirmed that specific antibodies induced by epitope peptide-fused proteins recognized intracellular regions of LMP2A. These results demonstrated that these three predictive epitopes not only were immunodominant B-cell epitopes of LMP2A, but also may be potential targets for applications in the design of diagnostic tools.