Interleukin-3/erythropoietin fusion proteins: in vitro effects on hematopoietic cells
| Autor: | N S, Weich, J, Tullai, E, Guido, M, McMahon, L K, Jolliffe, A F, Lopez, M A, Vadas, P A, Lowry, P J, Quesenberry, J, Rosen |
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| Rok vydání: | 1993 |
| Předmět: |
Erythroid Precursor Cells
Base Sequence Macrophages Recombinant Fusion Proteins Molecular Sequence Data Bone Marrow Cells Cell Differentiation CHO Cells DNA Hematopoietic Stem Cells Colony-Forming Units Assay Cricetinae Animals Humans Interleukin-3 Erythropoietin Cell Division Cells Cultured Granulocytes Plasmids |
| Zdroj: | Experimental hematology. 21(5) |
| ISSN: | 0301-472X |
| Popis: | Erythropoietin (Epo) acts synergistically with interleukin-3 (IL-3) to induce proliferation and differentiation of erythroid progenitors. This synergy occurs at IL-3 concentrations that have little or no effect alone. To determine whether optimal expansion of erythroid cells results when they are targeted by a molecule with both IL-3 and Epo activities, fusion proteins were generated and analyzed. Expression vectors were constructed in which the coding regions of human IL-3 and Epo cDNAs were joined by either a short (2 to 3 amino acids) or long (23 amino acids) linker sequence and expressed in Chinese hamster ovary (CHO) cells. Analysis of equilibrium binding properties of the IL-3 and Epo moieties revealed that in all fusion proteins each retained the ability to bind receptor. When IL-3 was connected to Epo by a short linker, the binding affinity of the IL-3 moiety was lower. In vitro proliferative activity of each moiety was observed on cell lines responsive to IL-3, Epo or a combination of the two cytokines. Fusion of IL-3 to Epo through its amino terminus was found to result in partial loss of its function. All the fusion proteins were biologically active on human bone marrow. When IL-3 was located at the amino domain of the protein, induction of erythroid colonies was similar to that of a mixture of IL-3 and Epo. These results indicate that biological integrity of both IL-3 and Epo can be maintained when these cytokines are fused, but that enhancement of erythropoiesis over that observed with a mixture of the two cytokines cannot be achieved by their fusion alone. Other requirements such as the coexpression of the IL-3 and Epo receptors and the sharing of a receptor subunit are likely to be needed for an optimal cell response to the fusion growth factors. |
| Databáze: | OpenAIRE |
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