A method of treating a cancer in a subject is disclosed, comprising: (1) isolating T cells from a subject; generating or expanding a population of T cells specific for a virus by a method comprising: stimulating T cells by culture in the presence of antigen presenting cells (APCs) presenting a peptide of the virus, wherein 10 to 25% of the media in which the cells are cultured is conditioned media obtained from a stimulation culture comprising T cells and APCs presenting a peptide of the virus; and (3) administering the generated or expanded population of T cells to a subject. Also disclosed are methods for generating or expanding a population of T cells specific for a virus.