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)|
|Number of pages||4|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1985|
ASJC Scopus subject areas
- Immunology and Allergy