Enhanced immunogenicity in mouse by recombinant BCG prime and protein boost based on latency antigen Rv1733c and/or...

Area of Science:

• Immunology
• Vaccinology
• Microbiology

Background:

• Bacillus Calmette-Guérin (BCG) is the sole licensed tuberculosis (TB) vaccine but has limitations in preventing latent TB.
• Overexpressing latency and reactivation antigens in BCG may improve its efficacy against latent TB.
• This study aimed to create recombinant BCG (rBCG) strains overexpressing Rv1733c and/or RpfE.

Purpose of the Study:

• To construct and characterize recombinant BCG strains (rBCGs) overexpressing the latency antigen Rv1733c and/or the resuscitation antigen RpfE.
• To evaluate the immunogenicity of these rBCGs in a mouse model using a prime-boost vaccination strategy.

Main Methods:

• Engineered BCG strains using episomal or integrative plasmids encoding Rv1733c and/or RpfE.
• Administered a prime-boost vaccination regimen in BALB/c mice with rBCGs and recombinant proteins.
• Assessed immune responses by measuring cytokine production (IFN-γ, TNF-α, IL-10, IL-4) from splenocytes stimulated ex vivo.

Main Results:

• rBCGs expressing Rv1733c or RpfE induced higher antigen-specific interferon-gamma (IFN-γ) levels.
• Integrative rBCG strains enhanced tumor necrosis factor-alpha (TNF-α) production.
• Favorable IFN-γ to interleukin-10 (IL-10) ratios were observed with rBCGs expressing target antigens.

Conclusions:

• The study demonstrates the immunogenicity of Rv1733c and RpfE antigens.
• These antigens show potential for enhancing BCG efficacy in a prime-boost vaccination strategy.
• Further development could lead to improved TB vaccines.