Memory phenotype CD8(+) T cells in IL-15 transgenic mice are involved in early protection against a primary infection with Listeria monocytogenes.
We recently constructed IL-15 transgenic (Tg) mice using cDNA encoding a secretable isoform of the IL-15 precursor protein under the control of an MHC class I promoter. The IL-15 Tg mice exhibited resistance against a primary infection with Listeria monocytogenes. The numbers of memory CD8(+) T cells were markedly increased in the IL-15 Tg mice following Listeria infection accompanied by sustained IL-15 production. The increased CD44(+)CD8(+) T cells in the infected IL-15 Tg mice were not specialized to recognize Listeria-specific antigen but produced a large amount of IFN-gamma in response to bystander stimulation exogenous IL-15 in combination with IL-12. Furthermore, Listeria-specific Th1 response by CD4(+) T cells was significantly augmented in the IL-15 Tg mice compared with control mice following Listeria infection. In vivo depletion of the CD8(+) T cells by anti-CD8 monoclonal antibody and adoptive transfer of the T cells from naive IL-15 Tg mice indicated that the CD8(+) T cells functioned not only to eliminate bacteria at the early stage of infection but also to promote Th1 response to L. monocytogenes. Overexpression of IL-15 shed light on a novel role of memory CD8(+) T cells in early protection and promotion of Th1 response against a primary infection with L. monocytogenes.
Laboratory of Host Defense and Germfree Life, Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, Nagoya, Japan.
T
T
Yajima
H
H
Nishimura
R
R
Ishimitsu
K
K
Yamamura
T
T
Watase
D H
DH
Busch
E G
EG
Pamer
H
H
Kuwano
Y
Y
Yoshikai
D019264:Adoptive Transfer; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D002478:Cells, Cultured; D007156:Immunologic Memory; D018664:Interleukin-12 / Q000494:pharmacology; D019409:Interleukin-15 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D007700:Kinetics; D008089:Listeria monocytogenes / Q000254:growth & development / Q000276:immunology; D008088:Listeriosis / Q000276:immunology* / Q000382:microbiology / Q000628:therapy; D008198:Lymph Nodes / Q000276:immunology; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D010537:Peritoneum / Q000276:immunology; D010641:Phenotype; D015996:Survival Rate; D016176:T-Lymphocyte Subsets / Q000145:classification
D000942:Antigens, Bacterial; D019409:Interleukin-15; D018664:Interleukin-12