Persistence of Memory CD8 T Cells in MHC Class I-Deficient Mice

Abstract

An understanding of how T cell memory is maintained is crucial for the rational design of vaccines. Memory T cells were shown to persist indefinitely in major histocompatibility complex (MHC) class I–deficient mice and retained the ability to make rapid cytokine responses upon reencounter with antigen. In addition, memory CD8 T cells, unlike naı̈ve cells, divided without MHC–T cell receptor interactions. This “homeostatic” proliferation is likely to be important in maintaining memory T cell numbers in the periphery. Thus, after naı̈ve CD8 T cells differentiate into memory cells, they evolve an MHC class I–independent “life-style” and do not require further stimulation with specific or cross-reactive antigen for their maintenance.