In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis

Background Mycobacterium tuberculosis (MTb) is a highly infectious pathogen and a global health threat due to its resilient cell wall and immune evasion strategies. Despite the availability of the antituberculosis Bacille Calmette-Guérin (BCG) vaccine, its efficacy varies (0%–80%) and gradually decr...

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Main Authors: Edward Kevin Bragais, Francisco M. Heralde III, Kim Claudette J. Fernandez, Salvador Eugenio C. Caoili, Leana Rich Herrera-Ong
Format: Article
Language:English
Published: Termedia Publishing House 2025-03-01
Series:BioTechnologia
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Online Access:https://www.biotechnologia-journal.org/-In-silico-screening-and-identification-of-CTL-and-HTL-epitopes-in-the-secreted-virulence,201461,0,2.html
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author Edward Kevin Bragais
Francisco M. Heralde III
Kim Claudette J. Fernandez
Salvador Eugenio C. Caoili
Leana Rich Herrera-Ong
author_facet Edward Kevin Bragais
Francisco M. Heralde III
Kim Claudette J. Fernandez
Salvador Eugenio C. Caoili
Leana Rich Herrera-Ong
author_sort Edward Kevin Bragais
collection DOAJ
description Background Mycobacterium tuberculosis (MTb) is a highly infectious pathogen and a global health threat due to its resilient cell wall and immune evasion strategies. Despite the availability of the antituberculosis Bacille Calmette-Guérin (BCG) vaccine, its efficacy varies (0%–80%) and gradually decreases over time. This study aimed to identify cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes in MTb secretory proteins using immunoinformatics tools. Material and methods The Protein Variability Server was used to identify highly conserved sequences, and epitope population coverage was estimated for the Southeast Asian (SEA) region. Selected epitopes were also docked to their major histocompatibility complex alleles. Results Five secretory proteins critical to MTb pathogenesis and virulence were identified as antigenic (antigenicity score > 0.4). Predicted epitopes had IC50 values ≤ 500 nM, indicating strong binding affinity, with an estimated 94% population coverage in SEA. All candidate epitopes were highly conserved (Shannon index ≤ 0.1) and showed no significant sequence similarity to human proteins, allergens, or toxic peptides. Docking analysis confirmed favorable binding to their corresponding HLA alleles, as indicated by low Gibbs free energy change (ΔG) values and dissociation constants (KD nM). Conclusions Overall, this study identified immunoactive CTL and HTL epitopes that could serve as promising candidates for future antiTB vaccine development. Further in vitro and in vivo studies are required to validate these preliminary findings.
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spelling doaj-art-a680475acffc407b8cebcaeac6430aab2025-08-20T02:30:32ZengTermedia Publishing HouseBioTechnologia0860-77962353-94612025-03-011061637610.5114/bta/201461201461In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosisEdward Kevin Bragais0Francisco M. Heralde III1Kim Claudette J. Fernandez2Salvador Eugenio C. Caoili3Leana Rich Herrera-Ong4Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Manila, PhilippinesDepartment of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Manila, PhilippinesDepartment of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Manila, PhilippinesDepartment of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Manila, PhilippinesDepartment of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Manila, PhilippinesBackground Mycobacterium tuberculosis (MTb) is a highly infectious pathogen and a global health threat due to its resilient cell wall and immune evasion strategies. Despite the availability of the antituberculosis Bacille Calmette-Guérin (BCG) vaccine, its efficacy varies (0%–80%) and gradually decreases over time. This study aimed to identify cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes in MTb secretory proteins using immunoinformatics tools. Material and methods The Protein Variability Server was used to identify highly conserved sequences, and epitope population coverage was estimated for the Southeast Asian (SEA) region. Selected epitopes were also docked to their major histocompatibility complex alleles. Results Five secretory proteins critical to MTb pathogenesis and virulence were identified as antigenic (antigenicity score > 0.4). Predicted epitopes had IC50 values ≤ 500 nM, indicating strong binding affinity, with an estimated 94% population coverage in SEA. All candidate epitopes were highly conserved (Shannon index ≤ 0.1) and showed no significant sequence similarity to human proteins, allergens, or toxic peptides. Docking analysis confirmed favorable binding to their corresponding HLA alleles, as indicated by low Gibbs free energy change (ΔG) values and dissociation constants (KD nM). Conclusions Overall, this study identified immunoactive CTL and HTL epitopes that could serve as promising candidates for future antiTB vaccine development. Further in vitro and in vivo studies are required to validate these preliminary findings.https://www.biotechnologia-journal.org/-In-silico-screening-and-identification-of-CTL-and-HTL-epitopes-in-the-secreted-virulence,201461,0,2.htmlmycobacterium tuberculosiscytotoxic t-cell epitopeshelper t-cell epitopesimmunoinformatics
spellingShingle Edward Kevin Bragais
Francisco M. Heralde III
Kim Claudette J. Fernandez
Salvador Eugenio C. Caoili
Leana Rich Herrera-Ong
In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis
BioTechnologia
mycobacterium tuberculosis
cytotoxic t-cell epitopes
helper t-cell epitopes
immunoinformatics
title In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis
title_full In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis
title_fullStr In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis
title_full_unstemmed In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis
title_short In silico screening and identification of CTL and HTL epitopes in the secreted virulence factors of Mycobacterium tuberculosis
title_sort in silico screening and identification of ctl and htl epitopes in the secreted virulence factors of mycobacterium tuberculosis
topic mycobacterium tuberculosis
cytotoxic t-cell epitopes
helper t-cell epitopes
immunoinformatics
url https://www.biotechnologia-journal.org/-In-silico-screening-and-identification-of-CTL-and-HTL-epitopes-in-the-secreted-virulence,201461,0,2.html
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