Innate Immunity Trained in the Protective Response of Vaccine Candidates Against Intracellular Pathogens

Area of Science:

• Immunology
• Infectious Diseases
• Vaccinology

Background:

• Trained innate immunity enhances immune cell responsiveness to pathogens.
• Stimuli like beta-glucan can induce trained immunity for improved defense.
• Understanding trained immunity is key for developing novel infection control strategies.

Purpose of the Study:

• To investigate if trained innate immunity enhances vaccine efficacy against Brucella ovis and Listeria monocytogenes.
• To evaluate the impact of beta-glucan and zymosan on vaccine models.
• To assess the protective effects against bacterial infections.

Main Methods:

• In vivo induction of trained innate immunity using beta-glucan or zymosan.
• Vaccination with attenuated or inactivated Brucella ovis and Listeria monocytogenes formulations.
• Challenge with target pathogens and assessment of vaccine-induced protection and immune responses.

Main Results:

• Beta-glucan demonstrated significant in vitro and in vivo reduction of bacterial infection compared to zymosan.
• Beta-glucan enhanced protection with inactivated Brucella ovis vaccines but not with attenuated ones.
• Beta-glucan did not improve Listeria monocytogenes vaccine efficacy, though some trained mice showed no detectable bacteria.

Conclusions:

• Trained innate immunity improves the protective efficacy of inactivated vaccines against Brucella ovis and Listeria monocytogenes.
• Live attenuated Brucella ovis vaccine efficacy was detrimentally affected by trained innate immunity.
• Overstimulation through increased beta-glucan doses may impair infection control, highlighting dose-dependency.