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Updated: Aug 8, 2026
An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions
Published on: March 14, 2016
Comparison of interleukin-22 and interleukin-10 soluble receptor complexes
Naomi J Logsdon1, Brandi C Jones, Kristopher Josephson
1Department of Microbiology and Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, AL 35294, USA.
Insights
Interleukin-22 (IL-22) and Interleukin-10 (IL-10) bind differently to their receptor chains. Specific receptor interactions, particularly involving IL-10R2, are crucial for IL-22 and IL-10 signaling pathways.
Area of Science:
- Immunology
- Structural Biology
- Biochemistry
Background:
- Interleukin-22 (IL-22) and Interleukin-10 (IL-10) are cytokines with distinct biological functions.
- Both IL-22 and IL-10 initiate cellular responses through receptor engagement, sharing the IL-10 receptor 2 (IL-10R2) chain but utilizing unique ligand-specific receptor chains (IL-22R and IL-10R1, respectively).
Purpose of the Study:
- To analyze the quaternary structures of IL-22 and IL-10 in complex with their soluble receptor chains.
- To elucidate the binding kinetics and affinities of IL-22 and IL-10 for their respective receptor components, including the shared IL-10R2.
Main Methods:
- Size exclusion chromatography was employed to determine the quaternary structures of IL-22 and IL-10 with soluble receptor chains.
- Surface plasmon resonance was utilized to measure the kinetic binding constants (kon/koff) and equilibrium dissociation constants (Keq) between the cytokines and receptor chains.
Main Results:
- IL-22 exists as a monomer and forms a 1:1 complex with soluble IL-22 receptor (sIL-22R) with a nanomolar binding affinity.
- IL-10, a homodimer, binds to a monomeric isomer (IL-10M1) with high affinity via soluble IL-10 receptor 1 (sIL-10R1).
- IL-10R2 shows low affinity for IL-22 or IL-10 alone but significantly increased affinity for the pre-formed IL-22/sIL-22R and IL-10/sIL-10R1 complexes, with specific receptor residues identified as key determinants of affinity differences.
Conclusions:
- The distinct quaternary structures and differential affinities for receptor chains underlie the specific signaling capabilities of IL-22 and IL-10.
- The shared IL-10R2 chain plays a critical role in potentiating ligand-receptor interactions, with specific residues mediating affinity variations crucial for cytokine function.
Abstract:
Interleukin-22 (IL-22) is a cellular homolog of IL-10 that stimulates the production of acute-phase reactants. IL-22 and IL-10 require different ligand-specific receptor chains (IL-22R and IL-10R1) but share a second receptor chain (IL-10R2) to initiate cellular responses. The quaternary structures and the ability of IL-22 and IL-10 to engage soluble (s) IL-10R1, IL-22R, IL-10R2 receptor chains were analyzed using size exclusion chromatography and surface plasmon resonance techniques. In contrast to IL-10, which is a homodimer, IL-22 is a monomer in solution that forms a 1:1 interaction with sIL-22R. Kinetic binding data reveal sIL-22R and sIL-10R1 exhibit specific nanomolar binding constants for IL-22 (k(on)/k(off) = 14.9 nM) and a monomeric isomer of IL-10 (IL-10M1) (k(on)/k(off) = 0.7 nM), respectively. In contrast, IL-10R2 exhibits essentially no affinity for IL-22 (K(eq) approximately 1 mM) or IL-10M1 (K(eq) approximately 2 mM) alone but displays a substantial increase in affinity for the IL-10/sIL-10R1 (K(eq) approximately 350 microM) and IL-22/sIL-22R (K(eq) approximately 45 microM) complexes. Three-dimensional models of IL-22 and IL-10 receptor complexes suggest two receptor residues (Gly-44 and Arg-96) are largely responsible for the marked differences in ligand affinity observed for sIL-10R1 and sIL-22R vs. sIL-10R2.
