Immune aging in two windows

A large single‑cell study finds immune cells do not age steadily but instead show two prominent remodeling events around the 40s and the 60s. These events are cell‑type specific (helper versus killer T cells), differ by sex, and coincide with a decline in cells' protein‑synthesis machinery. — If immune competence shifts in discrete age windows, public‑health interventions (vaccination schedules, screening, and anti‑inflammatory or rejuvenation therapies) could be timed and targeted to those windows for greater effectiveness and equity.