Development of a multi-epitope vaccine candidate targeting blood-stage of malaria through immunoinformatics approach

Malaria, a potentially fatal disease caused by various Plasmodium species, continues to be a significant global health burden, with Plasmodium falciparum responsible for over 90% of malaria mortality worldwide (Snow, 2015). Current treatments, primarily relying on chemotherapy, face challenges due to drug resistance and severe side effects, highlighting the need for more effective and sustainable solutions. Vaccine-based approaches offer a promising alternative, providing potential long-term immunity with reduced risk of resistance. This study aims to develop a robust multi-epitope vaccine targeting four key Plasmodium falciparum 3D7 proteins: PfPHB1, PfPHB2, PfHSP70, and PfGARP. These proteins were selected based on their crucial roles in the parasite's survival and pathogenicity, as well as their conserved sequences present during the blood stage of infection. Using an array of bioinformatics tools, we identified B cell epitopes, HTL epitopes, and CTL epitopes, ensuring their antigenicity, non-toxicity, and non-allergenicity. These epitopes were then assembled into a vaccine construct, enhanced with the FliC protein of Salmonella typhimurium as an adjuvant to boost the immune response. The vaccine construct's secondary and tertiary structures were predicted and refined using PSIPRED and AlphaFold2, respectively. Molecular docking studies demonstrated strong interactions between the vaccine and TLR5, indicating potential efficacy in inducing an immune response. Codon optimization and in silico cloning in Escherichia coli K12 ensured efficient expression of the vaccine construct. Immune simulation using the C-ImmSim server predicted a robust and comprehensive immune response, further validating the vaccine's potential. This in-silico study represents a significant step towards developing a multi-epitope vaccine for malaria, addressing the limitations of current treatments and paving the way for experimental validation and future clinical trials.