title: High-affinity receptor-mediated internalization and degradation of interleukin 2 in human T cells.
abstract: Receptor-mediated internalization and degradation of IL-2 were investigated in cell lines carrying human T cell leukemia/lymphoma (lymphotrophic) virus type I (HTLV-I) and PHA-treated normal PBL. The HTLV-I-carrying cell lines ILT-Yan and TL-Mor, and the PBL expressed both high- and low-affinity IL-2-R. However, another HTLV-I-carrying T cell line, MT-1, expressed mainly low-affinity receptors. Greater than 50% of the IL-2 bound to high-affinity receptors was internalized within 10 min when these cells were incubated at 37 degrees C. The internalized IL-2 was rapidly degraded and the products were excreted into the culture fluid. The t1/2 of IL-2 degradation in these cells was estimated as 60-80 min at 37 degrees C. The internalization and degradation of IL-2 were both temperature dependent. Light-microscopic autoradiography with 3H-labeled IL-2 confirmed the internalization of IL-2, and suggested that some IL-2 might be carried to the nucleus.
mesh_terms: D002451:Cell Compartmentation; D002460:Cell Line; D002472:Cell Transformation, Viral; D017977:Deltaretrovirus; D004705:Endocytosis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007376:Interleukin-2 / Q000378:metabolism*; D007700:Kinetics; D011971:Receptors, Immunologic / Q000378:metabolism*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000378:metabolism*; D013696:Temperature
chemical_list: D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2