Overexpression of IL-15 in vivo increases antigen-driven memory CD8+ T cells following a microbe exposure

Toshiki Yajima, Hitoshi Nishimura, Ryotaro Ishimitsu, Taketo Watase, Dirk H. Busch, Eric G. Pamer, Hiroyuki Kuwano, Yasunobu Yoshikai

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100 Citations (Scopus)


To elucidate potential roles of IL-15 in the maintenance of memory CD8+ T cells, we followed the fate of Ag-specific CD8+ T cells directly visualized with MHC class I tetramers coupled with listeriolysin O (LLO)91-99 in IL-15 transgenic (Tg) mice after Listeria monocytogenes infection. The numbers of LLO91-99-positive memory CD8+ T cells were significantly higher at 3 and 6 wk after infection than those in non-Tg mice. The LLO91-99-positive CD8+ T cells produced IFN-γ in response to LLO91-99, and an adoptive transfer of CD8+ T cells from IL-15 Tg mice infected with L. monocytogenes conferred a higher level of resistance against L. monocytogenes in normal mice. The CD44+CD8+ T cells from infected IL-15 Tg mice expressed the higher level of Bcl-2. Transferred CD44+CD8+ T cells divided more vigorously in naive IL-15 Tg mice than in non-Tg mice. These results suggest that IL-15 plays an important role in long-term maintenance of Ag-specific memory CD8+ T cells following microbial exposure via promotion of cell survival and homeostatic proliferation.

Original languageEnglish
Pages (from-to)1198-1203
Number of pages6
JournalJournal of Immunology
Issue number3
Publication statusPublished - Feb 1 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Immunology and Allergy
  • Immunology


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