NKT cells are relatively resistant to apoptosis

CD1d-restricted natural killer T (NKT) cells are relatively resistant to activation-induced apoptosis, a characteristic that seems to be acquired in the late stage of intrathymic development. On strong antigen stimulation, peripheral NKT cells respond by downregulating their antigen receptor, while preserving their functional activities. Receptor downregulation might contribute to the homeostasis of the peripheral NKT-cell population and thus has an important regulatory role in the immune system.