Abstract
Activation of lymphocytes by mitogenic lectins results in the production of a group of soluble factors, the lymphokines. Proliferation of activated T cells requires interaction of one of these lymphokines, interleukin 2 (IL 2), with its receptor. The induction of IL 2 receptor expression and IL 2 production may involve different activation signals; some mitogens or antigens may activate both, whereas others may activate only one. An increase in cytosolic free calcium concentrations ([Ca++](i) is one of the signals involved in cellular activation by lectins. By using the fluorescent indicator quin-2, we have demonstrated that increases in [Ca++](i) accompany phytohemagglutinin induced proliferative responses of human T lymphocytes. Preventing the increase in [Ca++](i) also prevents proliferation. We demonstrate that an increase in [Ca++](i) is not required for the expression of the IL 2 receptor, which is expressed even in the presence of extremely low external calcium concentrations. In contrast, IL 2 production requires an increase in [Ca++](i) and does not occur in the absence of extracellular free calcium. IL 2 production appears to be the critical step requiring transmembrane calcium flux. In the absence of transmembrane calcium flux and subsequent IL 2 production, lectins are not able to trigger DNA synthesis and cell proliferation.
Original language | English (US) |
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Pages (from-to) | 1640-1643 |
Number of pages | 4 |
Journal | Journal of Immunology |
Volume | 134 |
Issue number | 3 |
State | Published - 1985 |
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology