Do CD8 effector cells need IL-7R expression to become resting memory cells?
The role for IL-7R expression in the differentiation of effector T cells into resting memory remains controversial. Here, using a conditional IL-7R transgenic model, we were able to test directly whether CD8 effector T cells require IL-7R expression for their differentiation into resting memory cells. In the absence of IL-7R expression, effector cells transferred into "full" hosts underwent a protracted and unremitting contraction compared with IL-7R-expressing control cells and were unable to develop into long-term resting memory cells. Surprisingly, when the same effector cells were transferred into empty T-cell-deficient hosts, they could generate long-lived fully functional resting memory cells independently of IL-7R expression. Formation of these latter cells was found to be dependent on IL-15, because the same IL-7R-deficient effector cells were rapidly lost from IL-15-deficient hosts, having a half-life of less than 40 hours. Therefore, our data suggest that, under physiological conditions, both IL-7 and IL-15 synergize to promote the formation of memory cells directly by limiting the contraction of effectors that occurs following an immune response and that reexpression of IL-7R is a key checkpoint in the regulation of this process.
Buentke
Eva
E
Division of Immune Cell Biology, National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK.
Mathiot
Anne
A
Tolaini
Mauro
M
Di Santo
James
J
Zamoyska
Rose
R
Seddon
Benedict
B
D019264:Adoptive Transfer; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D007156:Immunologic Memory; D019409:Interleukin-15 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018345:Mice, Knockout; D008822:Mice, Transgenic; D020395:Receptors, Interleukin-7 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
D019409:Interleukin-15; D020395:Receptors, Interleukin-7