Stimulation-dependent induction of CD154 on a subset of CD4+ FoxP3+ T-regulatory cells

► We define the abilities of CD4 T-cell subsets to induce the expression of CD154. ► Expression of CD154 was induced in 40-60% of total, and FoxP3− effector, CD4 T cells. ► The percentage of CD154 expression among CD4 FoxP3+ Treg cells was up to only ~ 8-9%. ► CD154 induction by CD4 FoxP3+ Treg cells is regulated by cell-intrinsic mechanisms. ► Differential CD154 induction may play a key role to distinguish CD4 subset functions.