Multiepitope-based vaccine design by exploring antigenic potential among leptospiral lipoproteins using comprehensive immunoinformatics and structure-based approaches.

Leptospirosis is a tropical and globally neglected zoonotic disease caused by pathogenic spirochetes, Leptospira. Although the disease has been studied for decades, a potent or effective vaccine is not available so far. Efforts are being made to design an efficient vaccine candidate using different approaches. Immunoinformatics approaches have been proven to be promising in terms of time and cost. Here, we used immunoinformatics and structure-based approaches to evaluate antigenic B- and T-cell epitopes present on the leptospiral lipoproteins (LipL). The promiscuous overlapping epitopes (B-cell, T-cell, interferon (IFN)-γ positive, and non-allergens), which can induce humoral, cell-mediated, and innate immunity, were selected to generate a multiepitope chimeric vaccine. To enhance the vaccine immunogenicity, a Toll-like receptor (TLR) agonist was fused to the vaccine with a suitable linker. The chimeric vaccine structure was predicted for molecular docking studies with immune receptors. Moreover, the stability of the vaccine-immune receptor complexes was analyzed by normal mode analysis (NMA). The potency of the vaccine construct was predicted by the immune simulation tool. The study provides additional information toward constructing peptide-based chimeric vaccines  against Leptospira.