The role of glutathione in lymphocyte activation--II. Effects of buthionine sulfoximine and 2-cyclohexene-1-one on early and late activation events.
Depletion of intracellular glutathione (GSH) inhibits the lectin-induced activation response of human T lymphocytes. GSH-depleted lymphocytes undergo a partial activation response to lectins but fail to undergo blast transformation. Several lines of evidence indicate that the inhibition of lymphocyte activation in GSH-depleted lymphocytes involves relatively late activation events. Firstly, lectin stimulation induces significant 14C-AIB uptake, IL-2 production and expression of IL-2 receptor but a near complete inhibition of 3H-uridine and 3H-thymidine incorporation. Comparable levels of IL-2 production and IL-2 receptor expression are seen in GSH-depleted lymphocytes allowed to recover from GSH depletion during lectin stimulation. However, in the latter case, 3H-uridine and 3H-thymidine incorporation are normal, and activation is completely restored. Exogenous IL-2 cannot restore activation in GSH-depleted lymphocytes. Furthermore, lymphocytes remain highly susceptible to inhibition by GSH depletion even after 48 h of lectin stimulation which is sufficient to induce early activation events in the Go----G1 transition, such as IL-2 receptor expression and IL-2 production. Exogenous GSH partially restores intracellular GSH levels and completely restores lymphocyte activation in GSH-depleted lymphocytes. Despite comparable degrees of GSH depletion, DL-buthionine-SR-sulfoximine and 2-cyclohexene-1-one inhibit lymphocyte activation to different degrees. The inhibition by 2-cyclohexene-1-one is consistently greater than would be predicted based on glutathione depletion per se. We conclude that GSH-dependent processes are important in relatively late steps of the activation sequence characterized by nuclear events with relative sparing of essential early steps in activation, such as IL-2 receptor expression and IL-2 production. The approximate minimal intracellular GSH concentration necessary to sustain a normal activation response is 2 nmol per 10(7) lymphocytes.
Hamilos
D L
DL
National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206.
Mascali
J J
JJ
Wedner
H J
HJ
D000621:Aminoisobutyric Acids / Q000493:pharmacokinetics; D019328:Buthionine Sulfoximine; D003512:Cyclohexanones / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D005978:Glutathione / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000096:biosynthesis / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000502:physiology*; D008717:Methionine Sulfoximine / Q000031:analogs & derivatives / Q000494:pharmacology; D012313:RNA / Q000096:biosynthesis; D015375:Receptors, Interleukin-2 / Q000187:drug effects / Q000378:metabolism; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
D000621:Aminoisobutyric Acids; D003512:Cyclohexanones; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D008717:Methionine Sulfoximine; C028215:2-cyclohexen-1-one; D019328:Buthionine Sulfoximine; D012313:RNA; D004247:DNA; D005978:Glutathione