Designing a Recombinant Multi-epitope DNA Vaccine as Candidate for Protection against Pathogenic Leptospira Infection in Animals

Leptospirosis can cause severe disease and probable death in humans. Antigenic epitopes from pathogenic strains of the bacteria have shown potential for serving as vaccine candidates and play a key role in the sensitivity and specificity of immunodiagnostic tests. This in-vitro analysis was undertaken to develop a prototype recombinant DNA vaccine using in-silico epitope prediction method. Epitope prediction software programs predicted the most antigenic linear B-cell epitopes of OmpL1, LipL32, LipL41, Loa22, and LigA. Thirteen epitopes were predicted, connected by the Gly-Ser linker, and synthesized. The purity of the concentrated recombinant multi-epitope protein was assessed by restriction enzyme digestion and gel electrophoresis. In-vitro expression on mammalian Chinese Hamster Ovary cell line indicated strong cytoplasmic fluorescence produced based on an indirect immunofluorescence antibody test. The green color of the cytoplasm indicates successful transcribed and translated DNA as against the blue-stained nucleus observed in the un-transfected control group based on the indirect immunofluorescence antibody test. The findings of the current study showed high antibody binding potentials of the vaccine constructs, which could be used for diagnostic applications or as polyvalent vaccine candidates.