Structural and functional characterisation of ferret interleukin-2

Area of Science:

• Immunology
• Structural Biology
• Virology

Background:

• Ferrets are vital models for human viral infections like influenza, Hendra, and Nipah.
• Lack of species-specific immunological reagents hinders cellular immune response evaluation in ferrets.
• Interleukin 2 (IL-2) is a key cytokine for immune response assessment.

Purpose of the Study:

• To develop and characterize ferret recombinant Interleukin 2 (IL-2).
• To elucidate the three-dimensional structure of ferret IL-2.
• To assess the biological activity of ferret IL-2.

Main Methods:

• Expression and purification of ferret recombinant IL-2 with a C-terminal histidine tag.
• X-ray crystallography to determine the three-dimensional structure at 1.89 Å resolution.
• Stimulation of ferret lymph node cells with recombinant ferret IL-2 and analysis of mRNA expression.

Main Results:

• The first non-human IL-2 structure was determined at high resolution (1.89 Å).
• Ferret IL-2 exhibits the characteristic four-helix bundle cytokine fold but with conformational flexibility.
• This flexibility may affect receptor binding interactions, suggesting differences from human IL-2.
• Recombinant ferret IL-2 induced lymph node cell proliferation and expression of IFN-γ and Granzyme A mRNA.

Conclusions:

• Ferret IL-2 has been successfully produced, structurally characterized, and shown to be biologically active.
• The structural flexibility of ferret IL-2 may explain subtle differences in receptor binding compared to human IL-2.
• This work provides a critical reagent for advancing research on ferret immunology and viral pathogenesis.