Oxidatively stressed lymphocytes remain in Go/Gla on mitogenic stimulation

✍ Scribed by Duncan, David D. ;Lawrence, David A.

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 793 KB
• Volume: 5
• Category: Article
• ISSN: 0887-2082
• DOI: 10.1002/jbt.2570050405

✦ Synopsis

Thiol modifiers and oxidants inhibit lymphocyte activation. To investigate which of the many cell functions sensitive to oxidation are critical in this inhibition, mouse splenic lymphocytes were treated with oxidants prior to exposure to mitogen, and progression into the cell cycle was assayed. Different treatments were used to chemically dissect different potential targets within the cell: copper phenanthroline (CUP), to oxidize surface sulfhydryls; N-ethyl maleimide (NEM), to alkylate extra-and intracellular thiols; and hydrogen peroxide, which generates the highly reactive hydroxyl radical within the cell. Progression into the cell cycle was assayed with acridine orange (AO) and assays of interleukin-2 (IL-2) production and IL-2 receptor (ILQR) expression. The contribution of ADP-ribosylation to inhibition of mitogenesis was assessed using baminobenzamide (3AB) to inhibit adenosine 5-diphosphate (ADP)-ribose transferases. The results indicate that the CUP and NEM treatments both produce two independent inhibitory effects, that is, a failure in the production of and response to IL-2. Cells treated with these compounds were able to progress only through Gla upon mitogenic stimulation. H,O, had more complex effects. Both ADP-ribosylation and modulations of cytosolic Ca2+ were involved in the inhibitory effects. With lower inhibitory doses of H,O,, lymphocytes were completely unresponsive to mitogen and failed to exit Go upon mitogenic stimulation. If intra-and extracellular CaZ+ were buffered before treatment with H,O,, higher concentrations were required, and under these conditions cells were able to enter Gla but could not progress into Glb. Under neither of these conditions could cells produce IL-2 or express IL-2R.