A soluble interleukin 2 receptor produced by a normal alloreactive human T cell clone binds interleukin 2 with low affinity.

摘要: Several alloreactive human T cell clones derived from a rejected kidney graft were found to produce in their culture supernatants soluble interleukin 2 receptors (IL-2R) upon specific antigenic challenge (irradiated B line the graft's donor). Among them, 2B11, high producer clone, was used purify IL-2R preparation which analyzed, comparison with and low affinity cell-surface expressed by 2B11 cells, for its parameters of interaction set anti-IL-2R monoclonal antibodies (mAb) IL-2. This receptor purified chromatography (anti-IL-2R mAb column) sodium dodecyl sulfate gel electrophoresis is composed single chain 35,000 45,000 Da. Immunoradiometric assays (IRMA) at equilibrium up, using pairs directed against two separate epitopes on Tac antigen IL-2R, measure respective dissociation constant these IL-2R. They be identical those A 1:1 stoichiometry between both membrane species. Competition experiments binding allowed quantitative analysis concentration without need amino acid material up IRMA (detection limit 5 pM). The IL-2 determined various techniques including an radiolabeled results obtained led us conclude that binds (KD = 30 nM) (Tac antigen). Whereas 2.5% days after stimulation cells 25 pM), no (less than 0.07%) sites could detected therefore likely corresponds truncated, extracellular part antigen. amounts produced clone did not exceed 1 nM and, as expected studies, affect IL-2-induced proliferation. physiologic pathologic implications our are discussed.