2 weeks is ideal, but you will also need to optimize/limit the strength of stimulus and il-2 concentration to avoid AICD. Antigen + APC and low il-2 is the most natural and gentle stimulation to avoid AICD. Anti cd3/28 or strong antigenic peptides are more likely to cause AICD.

Thank you Joseph michael Cantor sir for your answer. If we culture those stimulated T cells in the absence of IL-2 . does it causes problem?

One more question; after the stimulated cell enter into log phase can we use those stimulated cell to perform other invitro assays or those T cell have still chance for AICD?