Macrophage assays test inflammatory hysteresis

This proposed study asks whether ageing makes human immune cells harder to guide out of inflammation. Macrophages are immune cells that can enter an inflammatory M1 state; cells from 20 younger and older donors would be tested along both directions. Resting cells would receive 11 doses of LPS, a bacterial signal that triggers inflammatory activation, for 24 hours. Matched M1 cells would then receive 11 doses of IL-4, an immune signal that promotes resolution, for 24 hours. For each donor, the team would compare the doses producing half of the maximum response. A gap wider than 1.0 log10 unit would indicate that cellular history shapes switching. An older-to-younger gap of at least 1.5-fold would support age-associated inflammatory entrenchment; similar curves would support reversible, dose-dependent switching.