IL-7 receptor expression levels do not identify CD8+ memory T lymphocyte precursors following peptide immunization.
Identification of the mechanisms underlying the survival of effector T cells and their differentiation into memory T lymphocytes are critically important to understanding memory development. Because cytokines regulate proliferation, differentiation, and survival of T lymphocytes, we hypothesized that cytokine signaling dictates the fate of effector T cells. To follow cytokine receptor expression during T cell responses, we transferred murine TCR transgenic T cells into naive recipients followed by immunization with peptide emulsified in adjuvant or pulsed on dendritic cells. Our findings did not correlate IL-7R alpha-chain and IL-2R beta-chain expression on effector CD8+ cells with the generation of memory T lymphocytes. However, we could correlate the extent of IL-7R alpha expression down-regulation on effector T cells with the level of inflammation generated by the immunization. Furthermore, our findings showed that the maintenance of a high level of IL-7R expression by effector T cells at the peak of the response does not preclude their death. This suggests that maintenance of IL-7R expression is not sufficient to prevent T cell contraction. Thus, our results indicate that expression of the IL-7R is not always a good marker for identifying precursors of memory T cells among effectors and that selective expression of the IL-7R by effector T cells should not be used to predict the success of vaccination.
Lacombe
Marie-Hélène
MH
Guy-Bernier Research Center, Maisonneuve-Rosemont Hospital and Department of Medicine, University of Montreal, Montreal, Quebec, Canada.
Hardy
Marie-Pierre
MP
Rooney
Julie
J
Labrecque
Nathalie
N
D019264:Adoptive Transfer; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000378:metabolism* / Q000637:transplantation; D007156:Immunologic Memory / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000008:administration & dosage* / Q000276:immunology*; D020395:Receptors, Interleukin-7 / Q000096:biosynthesis* / Q000235:genetics; D013234:Stem Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*
D010455:Peptides; D020395:Receptors, Interleukin-7