NEW VACCINE STRATEGIES TARGETING CELLULAR AND TRAINED IMMUNITY AGAINST INTRACELLULAR BACTERIA IN FISH

Area of Science:

• Aquaculture
• Immunology
• Microbiology

Background:

• Aquaculture expansion increases susceptibility to intracellular bacterial pathogens like Piscirickettsia salmonis and Edwardsiella spp.
• Intracellular pathogens evade humoral immunity, rendering conventional inactivated vaccines ineffective due to poor cell-mediated immunity (CMI) and trained immunity induction.
• Current disease control relies heavily on antibiotics, posing risks to sustainability and public health.

Purpose of the Study:

• To review and analyze novel strategies for stimulating CMI and trained immunity in fish against intracellular bacterial infections.
• To explore the mechanisms of these emerging immunotherapies and their potential applications in aquaculture.
• To discuss advanced antigen discovery and delivery systems, including in silico methods, nanolipids (LNPs), and recombinant bacteria.

Main Methods:

• Literature review and analysis of emerging strategies in fish immunology.
• Examination of in silico platforms for antigen identification.
• Assessment of advanced delivery systems (LNPs, recombinant BCG) and trained immunity concepts.

Main Results:

• CMI and trained immunity offer promising avenues for controlling intracellular bacterial infections in fish.
• In silico antigen discovery combined with advanced delivery systems can enhance vaccine efficacy.
• Trained immunity, through epigenetic and metabolic reprogramming, provides broad-spectrum protection.

Conclusions:

• Innovative vaccine platforms stimulating CMI and trained immunity are crucial for sustainable aquaculture.
• Redefining vaccine efficacy to include functional memory parameters is essential.
• These advancements can significantly decrease reliance on antibiotics in aquaculture disease management.