β-Glucan as Trained Immunity-Based Adjuvants for Rabies Vaccines in Dogs.

Area of Science:

• Immunology
• Vaccinology
• Veterinary Medicine

Background:

• Trained immunity mechanisms, induced by compounds like beta-glucans, involve epigenetic and metabolic reprogramming of innate immune cells.
• Recent advances highlight the potential of trained immunity for developing novel vaccine adjuvants.
• Understanding trained immunity's role in vivo is crucial for translating in vitro findings.

Purpose of the Study:

• To evaluate the immune training effects of beta-glucans in dogs.
• To assess beta-glucans' capacity to enhance the adaptive immune response to an inactivated rabies vaccine (Rabisin®).
• To explore beta-glucans as potential trained immunity-based adjuvants (TIbAs).

Main Methods:

• Dogs were injected with beta-glucan from Euglena gracilis one month before rabies vaccination.
• Vaccination involved Rabisin® alone or supplemented with beta-glucan.
• Trained innate immunity parameters, B and T-cell responses, and cytokine secretion were assessed.

Main Results:

• Adjuvantation of Rabisin® with beta-glucan elicited a higher B-lymphocyte immune response, crucial for rabies protection.
• Beta-glucan showed a tendency to stimulate T-cell responses, indicated by cytokine secretion profiles.
• Preliminary results suggest beta-glucan administration enhances vaccine immunogenicity in dogs.

Conclusions:

• Beta-glucans demonstrate potential as trained immunity-based adjuvants (TIbAs) in dogs.
• Co-administration or pre-administration of beta-glucan with Rabisin® shows promising results for enhancing vaccine immunogenicity.
• These findings offer new insights into trained immunity's impact on adaptive immune responses to vaccines in canines.