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T cells shoot from the waist: low dose IL‐15 induces snap arming of CD44low T lymphocytes in the absence of antigen.
Author(s) -
Tamang David L,
Alves Bryce,
Elliot Viki,
Fraiser Stephanie,
Redelman Doug,
Hudig Dorothy
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.663.18
Subject(s) - cytotoxic t cell , granzyme b , antigen , cytotoxicity , population , cd8 , granzyme , biology , t cell , il 2 receptor , interleukin 21 , immunology , antigen presenting cell , effector , microbiology and biotechnology , chemistry , immune system , perforin , in vitro , medicine , biochemistry , environmental health
The current paradigm for lymphocyte activation is that T cells require two signals, antigen recognition and co‐stimulation, to become cytotoxic over the course of 3–5 days. This report describes a novel observation whereby freshly isolated splenocytes without prior exposure to specific antigen became functionally cytotoxic within 24 hours after culture with low‐dose IL‐15 (7x10‐10 M). The observed cytotoxicity was great enough so that one P815 target was killed per CD8+ T cell. Cytotoxicity was T cell dependent, as measured by anti‐CD3 redirected 51Cr release to detect the activity of all T cells. Furthermore, the effector T cell population killed P815 targets even when CD44hi (memory effector‐associated phenotype) CD8+ T cells were depleted. Cytotoxic capacity was gained before granzyme B could be detectable by flow cytometry. Phenotypic markers for the T cell population resembled that of resting T cells. Since IL‐15 is physiologically bound to IL‐15 receptors of dendritic cells and IL‐15 message is produced by a variety of peripheral tissues, this work suggests that effector T cells may gain cytotoxic potential earlier than currently thought.