Interleukin 2 binding molecule distinct from the Tac protein: analysis of its role in formation of high-affinity receptors
| Autor: | Richard J. Robb, Cynthia M. Rusk, Junji Yodoi, Warner C. Greene |
|---|---|
| Rok vydání: | 1987 |
| Předmět: |
Interleukin 2
Receptor complex Cellular immunity T-Lymphocytes Receptors Antigen T-Cell Antigen-Antibody Complex Biology Antibodies Cell Line medicine Humans Receptors Immunologic Binding site Receptor Multidisciplinary Binding protein Lymphokine Receptors Interleukin-2 Tumor Necrosis Factor Receptor Superfamily Member 7 Kinetics Biochemistry Cell culture Antigens Surface Interleukin-2 Research Article medicine.drug |
| Zdroj: | Proceedings of the National Academy of Sciences. 84:2002-2006 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.84.7.2002 |
| Popis: | Interleukin 2 (IL-2) receptors on activated T cells exist in high- and low-affinity configurations, both of which share a ligand-binding component known as the Tac protein. Although almost all binding of IL-2 to such cells was inhibited by an antibody to Tac, the predominant component of binding on the natural killer (NK)-like cell line YT was resistant to this reagent. The ligand-binding component on YT cells also differed from Tac in its affinity constant (Kd approximately 8.2 X 10(-10) M vs. Kd approximately equal to 1.1 X 10(-8) M for low-affinity Tac sites) and in its susceptibility to inhibition by certain antibodies to IL-2. When the YT cells were stimulated in a manner that induced expression of the Tac protein, the IL-2 binding sites were converted to a high-affinity configuration (Kd approximately 1.8 X 10(-11) M). Thus, the original binding component on unstimulated YT cells appeared to combine with Tac and IL-2 to produce a high-affinity receptor complex. Use of bifunctional crosslinking agents following ligand binding to unstimulated YT cells yielded covalent IL-2-receptor complexes of 83 and 90 kDa. These complexes were similar in size to those derived from high-affinity receptors on activated T cells and shared a similar fragmentation pattern upon proteolysis. These results demonstrate the existence of a second IL-2 binding component in addition to the Tac protein and suggest that this component combines with Tac and IL-2 to form high-affinity receptor sites. |
| Databáze: | OpenAIRE |
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