Muscle macrophage regenerative response after squalene-adjuvanted influenza vaccination drives Th2-skewed response and is reduced with age.

ABSTRACT: Squalene-based adjuvants like MF59, and its research alternative AddaVax, induce transient muscle injury, but their working mechanisms downstream of muscle injury remain unclear. We show that an AddaVax-adjuvanted quadrivalent inactivated influenza virus vaccine (QIV) intramuscular injection triggers muscle regeneration-like immune processes and increases CX3CR1⁺Ly6C⁺ macrophages in the muscle and inguinal lymph nodes by day 4 post-injection. This leads to a Th2 skewed vaccine response with higher levels of vaccine specific IgG1 titers, and Th2-associated cytokines in the lungs 5 days after subsequent influenza viral challenge. In aged mice, the macrophage recruitment and polarization is diminished, which is consistent with age-associated muscle mass loss, reflecting

SUBMITTER: Noureddine M 

PROVIDER: S-EPMC11838721 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature