Immunity in Harmony: Utilizing Overlapping Epitopes for Tuberculosis and COVID-19 Protection

Area of Science:

• Immunology
• Vaccinology
• Infectious Disease Research

Background:

• The Bacillus Calmette-Guérin (BCG) vaccine, used for tuberculosis (TB), is associated with reduced incidence of other infections, including viral respiratory illnesses.
• BCG vaccination has been linked to lower COVID-19 rates in TB-endemic regions, suggesting potential cross-protective immunity.

Purpose of the Study:

• To investigate shared epitopes between Mycobacteria and SARS-CoV-2 using immunoinformatics.
• To evaluate the immunogenicity of identified shared epitopes.

Main Methods:

• Bioinformatic analysis to identify overlapping CD4, CD8, and B-cell epitopes between Mycobacteria and SARS-CoV-2.
• Synthesis and experimental validation of the most immunodominant T-cell epitope.
• Assessment of T-cell proliferation and inflammatory molecule expression.

Main Results:

• Identification of multiple overlapping T-cell and B-cell epitopes between Mycobacteria and SARS-CoV-2.
• Demonstrated promiscuous binding, high immunogenicity, and strong affinity of T-cell epitopes for HLA alleles.
• Experimental validation confirmed the ability of a key T-cell epitope to induce T-cell proliferation in COVID-19-vaccinated individuals.

Conclusions:

• Shared epitopes between Mycobacteria and SARS-CoV-2 may confer broader protection than virus-specific antigens alone.
• This cross-reactivity could explain enhanced immunity in BCG-vaccinated populations during pandemics.
• The identified epitopes represent a promising strategy for developing novel vaccines against emerging pathogens.