CD8A and viral infectious disease: Equally important, if cells activated physiologically behave like in vitro stimulated cells, T cells responding to antigen in vivo (for example tumor-specific CD8 T cells in tumor infiltrating lymphocytes preparations or antiviral CD8 T cells retrieved from the blood of a patient with active viral infection) may be vulnerable to bead-induced AICD or growth retardation during even an initial round of ex vivo stimulation.