That is correct! This protocol is carried out in serum free medium. Treg differentiation can be carried out like this but it is NOT OK for effector T cells as they will die unless serum is present. You can also differentiate Tregs in medium with serum. We have done it in 2%FCS containing medium and has given us great results. The proteins present in the serum can however retain TGFb and can thus impact negatively on the differentiation efficiency.
Write if you have any other doubts!
2015-09-22 08:30:08