title: Impaired expression of high affinity interleukin 2 receptor on activated lymphocytes from patients with systemic lupus erythematosus.
abstract: Peripheral lymphocytes stimulated with phytohemagglutinin (PHA-blasts) were examined for their responsiveness to exogenous interleukin 2 (IL-2). The proliferative response of PHA-blasts to IL-2 was significantly lower in patients with systemic lupus erythematosus (SLE) than in normal subjects. To clarify the reason for this defect, the expression of IL-2 receptor (IL-2R) on PHA-blasts was investigated using anti-Tac antibody and purified IL-2. Cytofluorometric analysis showed no statistical differences in the Tac positivity of PHA-blasts among normal subjects and patients with active and inactive SLE. Scatchard analysis using 125I-labeled anti-Tac monoclonal antibody revealed that the number of Tac epitopes on PHA-blasts was also not different among them. Next, the affinity of IL-2R expressed on PHA-blasts was determined by Scatchard analysis using radiolabeled IL-2 as a ligand. The number of high affinity IL-2R on the PHA-blasts was significantly decreased in patients with active and inactive SLE, as compared with normal subjects. The responsiveness of PHA-blasts to exogenous IL-2 was well correlated to the number of high affinity IL-2R, but not to the number of Tac epitopes or total IL-2R. Inasmuch as high affinity components of IL-2R are functionally active, the defective expression of high affinity IL-2R may be responsible for the T cell dysfunctions in SLE.
mesh_terms: D000911:Antibodies, Monoclonal; D002455:Cell Division; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008213:Lymphocyte Activation; D011971:Receptors, Immunologic / Q000032:analysis / Q000502:physiology*; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000911:Antibodies, Monoclonal; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D011994:Recombinant Proteins