title: Overexpression of IL-15 in vivo increases antigen-driven memory CD8+ T cells following a microbe exposure.
abstract: 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 LLO(91-99)-positive memory CD8+ T cells were significantly higher at 3 and 6 wk after infection than those in non-Tg mice. The LLO(91-99)-positive CD8+ T cells produced IFN-gamma in response to LLO(91-99), 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.
authors.affiliation: Laboratory of Host Defense, Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, Nagoya 466-8550, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yajima
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nishimura
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Ishimitsu
authors.forename: Taketo
authors.initials: T
authors.lastname: Watase
authors.forename: Dirk H
authors.initials: DH
authors.lastname: Busch
authors.forename: Eric G
authors.initials: EG
authors.lastname: Pamer
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kuwano
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Yoshikai
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000276:immunology*; D001427:Bacterial Toxins; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology / Q000473:pathology / Q000637:transplantation; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006360:Heat-Shock Proteins / Q000008:administration & dosage / Q000276:immunology*; D006460:Hemolysin Proteins; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D007156:Immunologic Memory / Q000235:genetics; D007274:Injections, Intraperitoneal; D019409:Interleukin-15 / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D007700:Kinetics; D008088:Listeriosis / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010446:Peptide Fragments / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000382:microbiology / Q000473:pathology / Q000637:transplantation
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D018984:Epitopes, T-Lymphocyte; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D015395:Histocompatibility Antigens Class I; D019409:Interleukin-15; D010446:Peptide Fragments; C038705:hlyA protein, Listeria monocytogenes