Memory CD8(+) T cell differentiation: initial antigen encounter triggers adevelopmental program in naive cells

The rules that govern memory T cell differentiation are not well understood . This study shows that after antigenic stimulation naive CD8(+)T cells bec ome committed to dividing at least seven times and differentiating into eff ector and memory cells. Once the parental naive CD8(+) T cell had been acti vated, this developmental process could not be interrupted and the daughter cells continued to divide and differentiate in the absence of further anti genic stimulation. These data indicate that initial antigen encounter trigg ers an instructive developmental program that does not require further anti genic stimulation and does not cease until memory CD8(+) T cell formation.