Human IL-2Rɑ subunit binding modulation of IL-2 through a decline in electrostatic interactions: A computational and...

Area of Science:

• Immunotherapy
• Computational Biology
• Protein Engineering

Background:

• High-dose Interleukin-2 (IL-2) demonstrates antitumor activity but is limited by severe toxicities, including Treg activation via high-affinity IL-2Rα binding.
• Therapeutic application of IL-2 is hampered by dose-limiting toxicities such as hypotension and vascular leak syndrome.

Purpose of the Study:

• To design and develop novel triple-mutant IL-2 variants using a rational computational approach.
• To improve the therapeutic index of IL-2-based immunotherapy by modulating its binding affinity to IL-2 receptor subunits.

Main Methods:

• Computational design of triple-mutant IL-2 variants.
• Molecular dynamic simulations and umbrella sampling to compute binding affinities to IL-2Rα.
• In vitro validation using flow cytometry to assess anti-CD25 mAb binding and IL-2 receptor subunit interactions.

Main Results:

• Novel triple-mutant IL-2 variants were successfully designed.
• Computed affinities indicated reduced binding of mutants to the IL-2Rα subunit compared to wild-type IL-2.
• In vitro experiments confirmed reduced binding to the IL-2Rα subunit without significantly disrupting interactions with IL-2Rβγc subunits.

Conclusions:

• Engineered triple-mutant IL-2 variants exhibit reduced affinity for IL-2Rα.
• These modifications hold potential for developing safer and more effective IL-2-based immunotherapies.
• Further studies are warranted to evaluate the in vivo efficacy and safety profile of these novel IL-2 variants.