Activation of lymphocytes by mitogenic lectins initiates a sequence of events that culminates in DNA synthesis and cell proliferation. The mitogenic effects of lectins on T lymphocytes leads to the production of a group of lymphokines including the interleukins. The binding of interleukin 2 (IL 2) to its receptor results in activation of the cell leading to DNA synthesis. An increase in cytosolic-free Ca++ ([Ca++](i)) is associated with activation of lymphocytes by mitogenic lectins and also appears to be a prerequisite for induction of DNA synthesis and cell proliferation. We have dtermined whether the proliferative response triggered by IL 2 binding to its receptor is associated with or requires an increase in [Ca++](i). Using human and murine IL 2-sensitive cell lines, we have demonstrated that the IL 2-induced proliferative response, in contrast to that induced by mitogens such as phytohemagglutinin or concanavalin A, is not accompanied by an increase in [Ca++](i) as monitored by the fluorescent indicator quin-2. Furthermore, IL 2-dependent triggering of lymphoblasts occurs in the presence of extremely low extracellular calcium concentrations that prevent transmembrane calcium flux. Activation of IL 2 receptor-bearing T cells, therefore, does not appear to be associated with or to require an increase in [Ca++](i) as part of the activation and signaling process. The critical step requiring calcium flux in cell signaling by mitogenic lectins must therefore occur elsewhere in the activation cascade.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Immunology|
|State||Published - 1985|
ASJC Scopus subject areas
- Immunology and Allergy