Overexpression of interleukin (IL)-7 leads to IL-15-independent generation of memory phenotype CD8+ T cells.
Transgenic (TG) mice expressing a high copy number of interleukin (IL)-7 cDNA under the control of the major histocomaptability complex (MHC) class II promoter display a 10-20-fold increase in total T cell numbers. Here, we show that the increase in T cell numbers in IL-7 TG mice is most apparent at the level of memory phenotype CD44hi CD122hi CD8+ cells. Based on studies with T cell receptor (TCR) TG mice crossed to IL-7 TG mice, increased levels of IL-7 may provide costimulation for TCR recognition of self-MHC ligands and thus cause naive CD8+ cells to proliferate and differentiate into memory phenotype cells. In addition, a marked increase in CD44hi CD122hi CD8+ cells was found in IL-7 TG IL-15(-) mice. Since these cell are rare in normal IL-15(-) mice, the dependency of memory phenotype CD8+ cells on IL-15 can be overcome by overexpression of IL-7.
Kieper
William C
WC
Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Tan
Joyce T
JT
Bondi-Boyd
Brea
B
Gapin
Laurent
L
Sprent
Jonathan
J
Ceredig
Rhodri
R
Surh
Charles D
CD
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000502:physiology*; D005434:Flow Cytometry; D007156:Immunologic Memory / Q000502:physiology*; D016130:Immunophenotyping; D019409:Interleukin-15 / Q000502:physiology*; D015851:Interleukin-7 / Q000235:genetics / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic
D019409:Interleukin-15; D015851:Interleukin-7