首页>
外文期刊>journal of cellular physiology
>Specific binding, internalization, and degradation of human recombinant interleukin‐3 by cells of the acute myelogenous, leukemia line, KG‐1
【24h】
Specific binding, internalization, and degradation of human recombinant interleukin‐3 by cells of the acute myelogenous, leukemia line, KG‐1
展开▼
机译：Specific binding, internalization, and degradation of human recombinant interleukin‐3 by cells of the acute myelogenous, leukemia line, KG‐1
AbstractWe have studied the interaction of35S‐labeled recombinant IL‐3 with the acute myelogenous leukemia cell line, KG‐1.35S‐IL‐3 bound to these cells in a time dependent, saturable, and specific manner at 4°C. Scatchard transformation of binding isotherms demonstrated the existence of a small number (200) of binding sites, with an apparent dissociation constant of 70‐105 pM. After a temperature shift from 4°C to 37°C, surface‐bound35S‐IL‐3 was rapidly internalized and processed into a trichloroacetic acid soluble form that was released into the medium. Experiments to address the specificity of the IL‐3 binding site revealed that neither human IL‐2, M‐CSF, erythropoietin, transferrin, bovine insulin, nor murine nerve growth factor compete with IL‐3 for binding to KG‐1 cells. Both human and gibbon recombinant IL‐3 and, surprisingly, human recombinant GM‐CSF effectively competed the binding of the labeled IL‐3 to these cells at 4°C. The competition by GM‐CSF was found to be concentration dependent, but much higher concentrations were required to achieve the levels obtained with IL‐3. These results suggest that GM‐CSF may also interact with the high‐affinity IL‐3 binding site on KG‐1 cells or, alternatively, that GM‐CSF binding to its own receptor may decrea
展开▼
