Designing a Multiple-Epitope Vaccine Candidate against Leishmania major and Leishmania infantum for Monocyte-Derived Exosome Preparation

Background: Leishmania is a vector-borne protozoon, which causes visceral, cutaneous and mucocutaneous leishmaniosis in human and animals. Monocyte-derived exosome vaccines can be used as prophylaxis and immunotherapy strategies. The aim of this study was to design a multiple-epitope candidate vaccine using leishmaniolysin (GP63) and rK39 proteins against Leishmania major and L. infantum for monocyte-derived exosome preparation. Methods: This study was carried out in Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran, 2023–2024. Effective immunodominant epitopes were selected from two antigenic proteins of GP63 and rK39 using various immunoinformatics and bioinformatics approaches. Vibrio cholerae β-subunit was used as an adjuvant to stimulate immune responses. Then, appropriate linkers were selected for the fusion of epitopes. The 3D model of candidate vaccine was predicted and validated. Results: This designed candidate vaccine could effectively be used as a prophylaxis strategy against leishmaniosis. Conclusion: A candidate vaccine was designed using bioinformatic and immunoinformatic studies with virtual acceptable quality; however, effectiveness of this vaccine should be verified through further in-vitro and in-vivo studies.