Immunologists map unknown biological machinery to produce memory T cells Immunologists at St. Jude Children's Research Hospital have mapped the previously unknown biological machinery by which the immune system generates T cells that kill bacteria, viruses, and tumor cells. The findings have multiple implications for how the adaptive immune system responds to infections to generate such memory T cells. The experiments revealed mechanisms that inhibit the development of the long-lived memory T cells that continually renew to protect the body over time. Blocking these inhibitory mechanisms with pharmacological or genetic approaches could boost protective immunity against infection and cancers. The researchers also discovered a subtype of memory T cells that they named terminal effector prime cells. Mapping the pathway that controls these cells raises the possibility of manipulating this pathway to enhance the ability of the immune system to kill microbes and cancer cells.