title: Insufficient interleukin-2 production from splenic CD4+ T cells causes impaired cell proliferation and early apoptosis in SAMP1, a strain of senescence-accelerated mouse.
abstract: We examined the proliferative and cytokine-producing activities of CD4+ T cells from young mice of the senescence-accelerated mouse strain SAMP1, which had shown markedly low T-dependent antibody-producing responses. When splenic T cells were cultured with concanavalin A (Con A), the percentage of CD4+ cells decreased earlier in SAMP1 than in C3H/He mice. At 40 hr of culture, the percentage of BrdU-labelled proliferating CD4+ cells increased strongly in C3H/He, but only slightly in SAMP1. When purified CD4+ T cells were cultured with Con A, the percentage of 5-bromo-2'-deoxyuridine (BrdU)-labelled cells peaked at around 48 hr of culture in both strains, but decreased significantly at 64 hr in SAMP1. The production of interleukin (IL)-2 but not IL-4 or interferon-gamma (IFN-gamma) was significantly lower in SAMP1 than in C3H/He at 48 hr of culture. IL-2 production was also markedly low in SAMP1, even under the stimulation of anti-CD3 with anti-CD28 antibodies. The frequency of cells producing IL-2 was significantly lower in SAMP1 than in C3H/He at 6-24 hr of culture with Con A. The percentage of annexin-positive and propidium iodide (PI)-negative apoptotic cells was significantly higher in SAMP1 than in C3H/He at 96 hr of culture. Exogenous IL-2 prevented the decrease in BrdU-labelled cells and the increase in apoptotic cells in the SAMP1 cell culture. These results indicate that SAMP1 CD4+ T cells cannot produce IL-2 at levels sufficient to support cell proliferation and survival. This may account for the weak T-dependent antibody response in SAMP1 mice.
authors.affiliation: Field of Regeneration Control, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Yasumitsu
authors.initials: Y
authors.lastname: Nishimura
authors.forename: Tomohide
authors.initials: T
authors.lastname: Hosokawa
authors.forename: Masamichi
authors.initials: M
authors.lastname: Hosono
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Baba
authors.forename: Masanori
authors.initials: M
authors.lastname: Hosokawa
mesh_terms: D019588:Aging, Premature / Q000276:immunology*; D000818:Animals; D017209:Apoptosis / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018929:Cell Culture Techniques; D002455:Cell Division / Q000276:immunology; D003208:Concanavalin A / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis*; D015847:Interleukin-4 / Q000096:biosynthesis; D051379:Mice; D008809:Mice, Inbred C3H; D008815:Mice, Inbred Strains; D013154:Spleen / Q000276:immunology*
chemical_list: D007376:Interleukin-2; D003208:Concanavalin A; D015847:Interleukin-4; D007371:Interferon-gamma