Designing a multi-epitope vaccine against the midgut-specific fibrinogen-related protein 1(FREP1) of Anopheles stephensi to enhance protection against the malaria parasite: a step beyond traditional vaccine development approaches.

Malaria has been a prominent health burden for decades globally. The complex life cycle of Plasmodium made numerous challenges in finding an effective candidate for developing a potent transmission-blocking vaccine (TBV) against malaria. A wide variety of genes of Anopheles mosquitoes' midgut and salivary gland play a pivotal role in the Plasmodium invasion and transmission inside the mosquito body. Targeting mosquitoes' genes offered new insights into developing a more efficient TBV with higher potential to impede the parasite transmission within the Anopheles. Fibrinogen-related protein 1(FREP1) is a mosquito midgut protein that plays a crucial role in parasite transmission. In this study, we opted for an immunoinformatic approach to target An. stephensi FREP1 protein for breaking the parasite cycle so that the life cycle of the parasite could be broken within the mosquito. The FREP1 vaccine was assessed for allergenicity, antigenicity, toxicity, immunogenicity, population coverage, conservancy, solubility, secondary and tertiary structure, which suggested the impeccable quality of the vaccine construct. The interaction between the vaccine and TLR4 receptor via molecular docking revealed an efficient, strong, and stable complex formation. The molecular dynamic simulation and in-silico immunization profiling indicated the remarkable free binding energy and higher potency of the vaccine to generate a significant immune response, respectively. Furthermore, codon optimization and in-silico cloning of the vaccine in Escherichia coli exhibited efficient protein expression. In summary, the FREP1 protein-based multiepitope vaccine can be considered an innovative formulation for targeting the parasite within the vector to impede malaria transmission and vector control as well.