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Site-Specific POxylation of Interleukin-4
Tessa Lühmann1, Marcel Schmidt1, Meike N Leiske2,3
1Institute of Pharmacy and Food Chemistry, University of Würzburg, Am Hubland, DE-97074 Würzburg, Germany.
ACS Biomaterials Science & Engineering
|January 20, 2021
Summary
Polymer conjugation is crucial for biologics. This study introduces poly(2-oxazoline) (POx) as a superior alternative to poly(ethylene glycol) (PEG), demonstrating enhanced synthesis and preserved biological activity for interleukin-4 (IL-4) conjugates.
Area of Science:
- Bioconjugation Chemistry
- Polymer Science
- Protein Engineering
Background:
- Poly(ethylene glycol) (PEG) dominates the polymer-bioconjugate market but faces immunological concerns.
- There is a growing need for alternative polymers to PEG in biologic drug development.
- Site-specific conjugation strategies are essential for creating well-defined bioconjugates.
Purpose of the Study:
- To develop and evaluate poly(2-oxazoline) (POx) as an alternative to PEG for conjugating to biologics.
- To utilize genetically engineered interleukin-4 (IL-4) with unnatural amino acids for site-specific POx conjugation.
- To compare the conjugation efficiency, stability, and biological activity of POx-IL-4 conjugates against PEG-IL-4 conjugates.
Main Methods:
- Genetically engineered interleukin-4 (IL-4) incorporating an unnatural amino acid.
- Bioorthogonal copper-catalyzed azide-alkyne cycloaddition (CuAAC) for site-specific conjugation.
- Electrophoresis, size exclusion chromatography, and analytical ultracentrifugation for conjugate characterization.
- TF-1 cell proliferation and STAT-6 phosphorylation assays to assess IL-4 biological activity.
- Thermal and chemical stability assessments.
Main Results:
- Poor conjugation yields were observed for IL-4-PEG conjugates.
- Poly(2-oxazoline) (POx) conjugation to IL-4 resulted in homogeneous conjugates with high yields.
- POxylation did not compromise the thermal or chemical stability of IL-4.
- POx-IL-4 conjugates retained wild-type IL-4 biological activity, confirmed by cell proliferation and signaling assays.
- Size exclusion chromatography and analytical ultracentrifugation confirmed conjugate homogeneity.
Conclusions:
- Poly(2-oxazoline) (POx) offers a promising alternative to poly(ethylene glycol) (PEG) for biologic conjugation.
- POxylation via CuAAC provides superior synthesis yields and conjugate homogeneity compared to PEGylation.
- POx conjugates exhibit excellent stability and preserve the biological activity of the therapeutic protein IL-4.
