title: IL 2 receptor induction on human T lymphocytes: role for IL 2 and monocytes.
abstract: In this report we studied the requirements for the activation and proliferation of highly purified human T lymphocytes. Purified T cells incubated for 3 days with PHA neither proliferate nor express IL 2 receptors as detected by FACS analysis with the use of anti-Tac antibodies. However, purified T cells incubated with Con A or anti-T3 moAb do not proliferate, albeit 30 to 35% T cells express Tac epitopes. The addition of IL 2, either natural purified or recombinant, resulted in both the appearance of Tac antigen and the proliferation of PHA-activated T cells. Much to our surprise, IL 2 did not induce proliferation of Tac-positive T cells activated by Con A or soluble anti-T3 unless monocytes were added to the cultures. These data suggested that two classes of IL 2 receptors might exist on T cells, one of which was not functionally involved in T cell proliferation. In keeping with this interpretation, we have been able to demonstrate, using a radiolabeled IL 2 binding assay, that anti-T3 moAb induced almost exclusively IL 2 receptors of low affinity (Kd = 30 to 70 X 10(-9) M) and that additional signals, provided by monocytes, are required for the acquisition of high affinity receptors. IL 2 itself can induce high affinity receptors on PHA-stimulated T cells but not on cells activated by Con A or anti-T3. In this latter case the physical presence of monocytes is required and cannot be substituted by IL 1, thus indicating a previously unreported role for monocytes. It is postulated that the contact of monocytes with T cells induces a switch from an inactive low affinity conformation of the IL 2 receptor to a functional high affinity one.
authors.forename: H
authors.initials: H
authors.lastname: Wakasugi
authors.forename: J
authors.initials: J
authors.lastname: Bertoglio
authors.forename: T
authors.initials: T
authors.lastname: Tursz
authors.forename: D
authors.initials: D
authors.lastname: Fradelizi
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D001665:Binding Sites; D003208:Concanavalin A / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology; D007376:Interleukin-2 / Q000378:metabolism / Q000502:physiology*; D008213:Lymphocyte Activation; D009000:Monocytes / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011971:Receptors, Immunologic / Q000032:analysis / Q000096:biosynthesis*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007375:Interleukin-1; D007376:Interleukin-2; D010835:Phytohemagglutinins; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7; D003208:Concanavalin A