Granzyme-B (gzm-B) production following short-term in vitro stimulation, however, is a distinguishing feature of virus-specific effector CD8+ T-cells that have recently encountered antigen in vivo, through either infection or vaccination (with induction from memory CD8+ T-cells requiring >24 h of in vitro stimulation)16–18. The gene discussed is CD8A; the disease is infection.