Date of Completion

2025

Document Type

Thesis

Degree Name

Bachelor of Science in Biochemistry

Keywords

Vaccine, Bioinformatics

Abstract

Leptospirosis is a globally neglected zoonotic disease caused by the spirochete bacterium Leptospira interrogans, posing a significant public health burden in tropical and subtropical regions. Although antibiotic therapy remains the primary treatment for most bacterial infections, Leptospira interrogans has exhibited increasing resistance to antimicrobial agents in recent years. This escalating resistance reinforces the demand for alternative prophylactic strategies, prompting further research into B-cell peptide epitope-based vaccines as a long-term solution for disease control. This study investigated the outer membrane proteins LIC11574 and LIC13411 from L. interrogans as potential sources of B-cell peptide epitopes for the rational development of an anti-L. interrogans vaccine. This study utilized bioinformatic tools to identify candidate B-cell epitopes derived from proteins based on predicted antigenicity, non-allergenicity, and immunogenicity. A total of 69 16-mer and 68 18-mer epitopes were identified in LIC11574, while LIC13411 yielded 112 16-mer and 123 18-mer epitopes. Structural investigation revealed that the identified B-cell peptide epitopes were predominantly located within α-helical regions, whereas the remaining sequences were distributed across β-sheet structures and loop regions. This distribution suggests favorable exposure for molecular and immunological recognition. The topranked B-cell peptide epitopes of LIC11574 and LIC13411, selected for their antigenic and nonallergenic characteristics, were successfully docked with the HLA-DRB1*15 molecule, exhibiting promising binding affinity values ranging from -12.6 to -14.9 kcal/mol. Immune simulations also revealed that the multi-epitope vaccines constructed using the selected peptides were able to induce B-cell and helper T-cell activity, indicating a favorable host immune response. Overall, these findings suggest that LIC11574 and LIC13411 are viable sources of B-cell peptide epitopes for the design and development of multi-epitope vaccines against leptospirosis. Further studies should focus on investigating the in vivo immunological landscape following exposure to these peptide epitopes, optimizing their delivery, and assessing safety.

First Advisor

Nedrick T. Distor, RCh, MSc

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