Effector memory CD8+ T cells are resistant to apoptosis

Based upon their migrating properties and effector functions, CD8(+) T cells have been further classified into central memory (T-CM) and two types of effector memory (T-EM and T-EMRA) cells. These memory cells display distinct replicative characteristics. Because apoptosis plays an important role in cellular homeostasis, we have examined the relative sensitivity of naive (T-N) and different memory CD8+ T cells to apoptosis. We show that both T-EM and T-EMRA CD8+ T cells are resistant to apoptosis, whereas T-N and T-CM CD8(+) T cells are sensitive to apoptosis.