IL-7R Target Deep Dive
Autoimmune Disease Targeting
Biological Context
Interleukin-7 Receptor alpha (IL-7Rα, CD127) is a cytokine receptor subunit essential for T-cell development, B-cell lymphopoiesis, and memory T-cell homeostasis. It pairs with the common γ-chain (γc) on lymphocyte surfaces and signals through JAK1/JAK3 when IL-7 binds.
Why it matters: Dysregulated IL-7 signaling is a driver in T-cell acute lymphoblastic leukemia (T-ALL) — gain-of-function IL-7Rα mutations are found in a subset of pediatric T-ALL patients. It is also implicated in autoimmune disease, where blocking IL-7Rα can test whether pathogenic T-cell survival depends on this pathway. The antagonist antibody GSK2618960 was evaluated in phase I; a planned phase IIa Sjögren study (NCT03239600) was withdrawn before enrollment. A de novo binder here is a research hypothesis, not an established clinical-development path.
The Goal: Design a high-affinity binder that occupies IL-7Rα’s ligand-binding groove, preventing native IL-7 from engaging.
Interactive Structure
The viewer below shows IL-7Rα (Chain B) bound to its cytokine IL-7 (Chain A).
Non-interactive alternative: The target-specification table below describes the relevant chains and interface residues. You can also open the 3DI2 structure record or download its PDB coordinates. Manipulating the 3D viewer is optional.
- Rotate: Left-click and drag
- Zoom: Scroll wheel
- Pan: Right-click (or Ctrl+Left-click) and drag
Design Mission
Create a binder that occupies the cytokine-binding groove of IL-7Rα, preventing IL-7 from docking.
Target Specifications
| Feature | Detail |
|---|---|
| Target Name | IL-7Rα (CD127) extracellular domain |
| PDB ID | 3DI2 |
| Target Chain | Chain B |
| Binder to mimic | Chain A (IL-7) |
| Entry caveat | Target chain B carries I118V; ligand chain A carries E106A. The course steering set does not include either position. |
| PDB-derived interface contacts (≤5 Å) | S31, L57, V58, E59, K77, K78, F79, L80, L81, I82, T104, K138, Y139, H191, Y192, F193 |
| Candidate steering set | B80,B81,B82,B192,B193 (L80, L81, I82, Y192, F193), spanning the hydrophobic ridge and aromatic contact cluster |
These are every IL-7Rα residue with any heavy atom within 5 Å of IL-7 in 3DI2. The smaller course set samples two contact clusters, but proximity does not establish energetic-hotspot status. Treat the set as a geometry-derived starting point and compare alternative subsets.
Strategy Tips
- Download PDB
3DI2. - Clean the structure: Keep Chain B (IL-7Rα). Remove Chain A (IL-7) and any crystallographic partners (chains C, D).
- Define steering residues: Begin with
B80,B81,B82,B192,B193in RFdiffusion / BindCraft, then inspect whether the resulting interfaces cover both clusters. - Size matters: IL-7 itself is small (~150 aa) and compact. A 60–100 aa minibinder is a reasonable teaching-scale hypothesis. Potential clash with the nearby γc subunit must be modeled separately because γc is absent from 3DI2.
Reference
- McElroy, C.A. et al. (2009). Structural and biophysical studies of the human IL-7/IL-7Rα complex. Structure 17, 54–65. doi:10.1016/j.str.2008.10.019 — primary citation for 3DI2.