IL-15 is critical for the maintenance and innate functions of self-specific CD8(+) T cells.
IL-15 is a pleiotropic cytokine involved in host defense as well as autoimmunity. IL-15-deficient mice show a decrease of memory phenotype (MP) CD8(+) T cells, which develop naturally in naïve mice and whose origin is unclear. It has been shown that self-specific CD8(+) T cells developed in male H-Y antigen-specific TCR transgenic mice share many similarities with naturally occurring MP CD8(+) T cells in normal mice. In this study, we found that H-Y antigen-specific CD8(+) T cells in male but not female mice decreased when they were crossed with IL-15-deficient mice, mainly due to impaired peripheral maintenance. The self-specific TCR transgenic CD8(+) T cells developed in IL-15-deficient mice showed altered surface phenotypes and reduced effector functions ex vivo. Bystander activation of the self-specific CD8(+) T cells was induced in vivo during infection with Listeria monocytogenes, in which proliferation but not IFN-gamma production was IL-15-dependent. These results indicated important roles for IL-15 in the maintenance and functions of self-specific CD8(+) T cells, which may be included in the naturally occurring MP CD8(+) T-cell population in naïve normal mice and participate in innate host defense responses.
Itsumi
Momoe
M
Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
Yoshikai
Yasunobu
Y
Yamada
Hisakata
H
D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000382:microbiology; D049109:Cell Proliferation; D005260:Female; D005434:Flow Cytometry; D018960:Hyaluronan Receptors / Q000276:immunology; D007113:Immunity, Innate / Q000276:immunology*; D007156:Immunologic Memory / Q000276:immunology; D019409:Interleukin-15 / Q000172:deficiency / Q000235:genetics / Q000276:immunology*; D053646:Interleukin-2 Receptor beta Subunit / Q000276:immunology; D008089:Listeria monocytogenes / Q000276:immunology; D008088:Listeriosis / Q000276:immunology / Q000382:microbiology / Q000628:therapy; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000172:deficiency / Q000235:genetics / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology
C476399:Cd44 protein, mouse; D018960:Hyaluronan Receptors; C508022:Il2rb protein, mouse; D019409:Interleukin-15; D053646:Interleukin-2 Receptor beta Subunit; D011948:Receptors, Antigen, T-Cell