Long-Acting Human Interleukin 2 Bioconjugate Modified with Fatty Acids by Sortase A

Area of Science:

• Biotechnology
• Immunotherapy
• Protein Engineering

Background:

• Human Interleukin 2 (IL-2) is a potent therapeutic for cancer and autoimmune diseases.
• A key limitation of IL-2 therapy is its short in vivo half-life, leading to rapid renal clearance.
• Fatty acid modification is a strategy to enhance protein half-life and tissue penetration.

Purpose of the Study:

• To engineer a long-acting IL-2 bioconjugate with improved pharmacokinetic properties.
• To utilize sortase A (srtA) for site-specific fatty acid conjugation to IL-2.
• To evaluate the biological activity and pharmacokinetic profile of the novel IL-2 bioconjugate.

Main Methods:

• Designed and optimized IL-2 analogues with varying peptide linkers for srtA recognition.
• Conjugated six different fatty acid moieties with distinct hydrophilic spacers to the optimal IL-2 analogue (A3) via srtA.
• Screened resulting bioconjugates for in vitro biological activity and in vivo pharmacokinetic properties.

Main Results:

• Analogue A3 was selected as the optimal IL-2 construct for further modification.
• Bioconjugate B6, modified with fatty acids via srtA, demonstrated near-optimal in vitro biological activity.
• B6 exhibited enhanced albumin binding and significantly improved in vivo pharmacokinetic properties compared to native IL-2.

Conclusions:

• A novel IL-2 bioconjugate, B6, was successfully developed using srtA-mediated fatty acid conjugation.
• B6 demonstrates potential as a next-generation, long-acting IL-2 immunotherapeutic agent.
• Fatty acid modification via srtA is an effective strategy for improving IL-2 pharmacokinetics.