An in vitro expansion process for rapid expansion of antigen specific T cells, such as allogeneic antigen specific T cells comprising the steps culturing in a gas permeable vessel a population of PBMCs (such as allogeneic PBMCs) in the presence of antigen, for example a peptide or peptide mix relevant to a target antigen(s), in the presence of an exogenous cytokine characterized in that the expansion to provide the desired population of T cells is 14 days or less, for example 9, 10, 11 or 12 days, such as 10 days. The disclosure also extends to T cell populations generated by and obtained from the method and the use of same in therapy.
