title: High affinity binding of human interleukin 4 to cell lines.
abstract: Purified human recombinant interleukin 4 (IL-4) was radio iodinated to high specific radioactivity without loss of biological activity. 125I-IL-4 bound specifically to the Burkitt lymphoma Jijoye cells and other cell lines. Jijoye cells showed a high affinity for 125I-IL-4 (Kd approximately equal to 7 10(-11) M) and displayed 1200-1400 specific receptors per cell at 4 degrees C or 37 degrees C. The equilibrium dissociation constant (Kd) corresponds to the IL-4 concentration which induces 50% maximal expression of the low affinity IgE receptor (Fc epsilon RL/CD23) on Jijoye cells. At 4 degrees C the rate constant of association K1 is 1.7 x 10(6) M-1 s-1 and the rate contant of dissociation k -1 is 1.3 x 10(-4) s-1 (t 1/2 = 91 min.) No human recombinant lymphokines other than IL-4 were able to compete for the binding of 125I-IL-4 to its receptor.
mesh_terms: D001667:Binding, Competitive; D006801:Humans; D015847:Interleukin-4; D007378:Interleukins / Q000378:metabolism*; D007700:Kinetics; D008222:Lymphokines / Q000378:metabolism; D011961:Receptors, Fc / Q000096:biosynthesis; D017455:Receptors, IgE; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured / Q000378:metabolism*
chemical_list: D007378:Interleukins; D008222:Lymphokines; D011961:Receptors, Fc; D017455:Receptors, IgE; D011994:Recombinant Proteins; D015847:Interleukin-4