Two subsets of memory T lymphocytes with distinct homing potentials and effector functions

F Sallusto, D Lenig, R Förster, M Lipp, A Lanzavecchia - Nature, 1999 - nature.com
F Sallusto, D Lenig, R Förster, M Lipp, A Lanzavecchia
Nature, 1999nature.com
Naive T lymphocytes travel to T-cell areas of secondary lymphoid organs in search of
antigen presented by dendritic cells,. Once activated, they proliferate vigorously, generating
effector cells that can migrate to B-cell areas or to inflamed tissues,,,. A fraction of primed T
lymphocytes persists as circulating memory cells that can confer protection and give, upon
secondary challenge, a qualitatively different and quantitatively enhanced response,,. The
nature of the cells that mediate the different facets of immunological memory remains …
Abstract
Naive T lymphocytes travel to T-cell areas of secondary lymphoid organs in search of antigen presented by dendritic cells,. Once activated, they proliferate vigorously, generating effector cells that can migrate to B-cell areas or to inflamed tissues,,,. A fraction of primed T lymphocytes persists as circulating memory cells that can confer protection and give, upon secondary challenge, a qualitatively different and quantitatively enhanced response,,. The nature of the cells that mediate the different facets of immunological memory remains unresolved. Here we show that expression of CCR7, a chemokine receptor that controls homing to secondary lymphoid organs, divides human memory T cells into two functionally distinct subsets. CCR7- memory cells express receptors for migration to inflamed tissues and display immediate effector function. In contrast, CCR7+ memory cells express lymph-node homing receptors and lack immediate effector function, but efficiently stimulate dendritic cells and differentiate into CCR7- effector cells upon secondary stimulation. The CCR7+ and CCR7- T cells, which we have named central memory (TCM) and effector memory (TEM), differentiate in a step-wise fashion from naive T cells, persist for years after immunization and allow a division of labour in the memory response.
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