title: Regulation of interleukin 2 receptor expression on a human cytotoxic T lymphocyte clone, synergism between alloantigenic stimulation and interleukin 2.
abstract: A human T cell clone (termed 40.2.6) established from a rejected human kidney allograft has been studied for its ability to express membrane IL 2 receptors in response to antigen (irradiated cells from the graft's donor) and recombinant IL 2 (rec-IL 2). On antigenic stimulation, the 40.2.6 clone produced low levels (0.15 U/ml) of IL 2 (peak at 24 hr) and incorporated (3H)thymidine (peak at 48 hr). This incorporation was strongly enhanced on addition of rec-IL 2 and was inhibited by the 33B31 antibody, an anti-human IL 2 receptor monoclonal antibody (Mab). The 125I-labeled 33B31 Mab has been used to quantify the density of IL 2 receptors on 40.2.6 cells. Cells not re-exposed to antigen or rec-IL 2 had a level of 33B31-binding sites which declined rapidly (10% of starting value after 2 days). This level remained much more stable when rec-IL 2 (1 U/ml) was present in the medium (80% at day 2). Antigen induced a three- to eightfold increase in the level of 33B31-binding sites which peaked at 24 hr and then declined. When a similar antigenic stimulation was performed in the presence of rec-IL 2 (1 U/ml), the level of 33B31-binding sites peaked at a higher value (eight- to 20-fold increase at day 2), and its subsequent decline was slower. These potentiating effects of rec-IL 2 were dose-dependent and occurred at low concentrations corresponding to the saturation by rec-IL 2 of high affinity IL 2 receptor sites. Finally, high affinity IL 2 receptors, as measured by the binding of 35S-labeled rec-IL 2, were found to be similarly up-regulated by antigen and rec-IL 2. Together, our results obtained on a monoclonal human T cell population with highly purified rec-IL 2 demonstrate that rec-IL 2 and antigen act in synergy to induce the expression of both high and low affinity membrane IL 2 receptors.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D001667:Binding, Competitive; D002470:Cell Survival; D002999:Clone Cells / Q000276:immunology / Q000378:metabolism; D004306:Dose-Response Relationship, Immunologic; D004357:Drug Synergism; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism* / Q000502:physiology; D007519:Isoantigens / Q000276:immunology*; D007959:Lymphocyte Culture Test, Mixed; D051381:Rats; D011971:Receptors, Immunologic / Q000032:analysis / Q000378:metabolism*; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins / Q000502:physiology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D007519:Isoantigens; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins