The invention relates to a method of inducing Foxp3 expression in a T cell comprising(i) stimulating a T cell(ii) inhibiting signalling via PI3K alpha or PI3K delta or m-TOR or Akt in said T cell, wherein said inhibition is commenced 10 to 22 hours after the stimulation of (i). The invention also relates to certain uses of PI3K inhibitors, PI3K inhibitors for particular uses, and kits.展开▼