BCG vaccination stimulates integrated organ immunity by feedback of the adaptive immune response to imprint prolonged innate antiviral resistance.

ABSTRACT: Bacille Calmette-Guérin (BCG) vaccination can confer nonspecific protection against heterologous pathogens. However, the underlying mechanisms remain mysterious. We show that mice vaccinated intravenously with BCG exhibited reduced weight loss and/or improved viral clearance when challenged with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 B.1.351) or PR8 influenza. Protection was first evident between 14 and 21 d post-vaccination and lasted ∼3 months. Notably, BCG induced a biphasic innate response and robust antigen-specific type 1 helper T cell (T_H1 cell) responses in the lungs. MyD88 signaling was essential for innate and T_H1 cell responses, and protection against SARS-CoV-2. Depletion of CD4⁺ T cells or interferon (IFN)-γ activity before

SUBMITTER: Lee A 

PROVIDER: S-EPMC10932731 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature