title: A novel role of IL-15 in early activation of memory CD8+ CTL after reinfection.
abstract: A rapid induction of effector functions in memory T cells provides rapid and intensified protection against reinfection. To determine potential roles of IL-15 in early expansion and activation of memory CD8+ T cells in secondary immune response, we examined the cell division and cytotoxicity of memory CD8+ T cells expressing OVA(257-264)/Kb-specific TCR that were transferred into IL-15-transgenic (Tg) mice, IL-15 knockout (KO) mice, or control C57BL/6 mice followed by challenge with recombinant Listeria monocytogenes expressing OVA (rLM-OVA). In vivo CTL activities and expression of granzyme B of the transferred CD8+ T cells were significantly higher in the IL-15 Tg mice but lower in the IL-15 KO mice than those in control mice at the early stage after challenge with rLM-OVA. In contrast, there was no difference in the cell division in IL-15 Tg mice and IL-15 KO mice compared with those in control mice. In vivo administration of rIL-15 conferred robust protection against reinfection via induction of granzyme B in the memory CD8+ T cells. These results suggest that IL-15 plays an important role in early activation of memory CD8+ T cells.
authors.affiliation: Division of Host Defense, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan. yajimato@biored.kyushu-u.ac.jp
authors.forename: Toshiki
authors.initials: T
authors.lastname: Yajima
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nishimura
authors.forename: Subash
authors.initials: S
authors.lastname: Sad
authors.forename: Hao
authors.initials: H
authors.lastname: Shen
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; D007114:Immunization; D007156:Immunologic Memory; D019409:Interleukin-15 / Q000172:deficiency / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D008089:Listeria monocytogenes / Q000276:immunology / Q000472:pathogenicity; D008088:Listeriosis / Q000276:immunology / Q000517:prevention & control; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011994:Recombinant Proteins / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D019409:Interleukin-15; D011994:Recombinant Proteins