Embodiments of the disclosure encompass methods for generating or expanding a population of immune cells specific for a virus, comprising stimulating immune cells specific for a virus by culturing peripheral blood mononuclear cells (PBMCs) in cell culture medium comprising human platelet lysate in the presence of: (i) one or more peptides corresponding to all or part of one or more antigens of the virus; or (ii) antigen presenting cells (APCs) presenting one or more peptides corresponding to all or part of one or more antigens of the virus. In particular embodiments, the cell culture medium comprises a particular percentage of human platelet lysate and/or the PBMCs are depleted of CD45RA-positive cells, for example.