Production of biologically active equine interleukin 12 through expression of p35, p40 and single chain IL-12 in mammalian and baculovirus expression systems.
Authors: McMonagle E L, Taylor S, van Zuilekom H, Sanders L, Scholtes N, Keanie L J, Hopkins C A, Logan N A, Bain D, Argyle D J, Onions D E, Schijns V E, Nicolson L
Journal: Equine veterinary journal
Summary
# Editorial Summary Interleukin-12 (IL-12) is a critical cytokine for driving cell-mediated immunity, and its therapeutic potential in treating cancer, infection and inflammatory disease has been demonstrated across multiple species—yet equine-specific IL-12 had not been successfully produced until this work. McMonagle and colleagues expressed functional equine IL-12 using three approaches: separate p35 and p40 subunits in both mammalian and insect cell systems, and a single-chain fusion construct in mammalian cells, with biological activity confirmed by measuring interferon-gamma (IFN-γ) production in equine lymph node cells. All three expression strategies generated bioactive IL-12, with conditioned media from transfected mammalian cells and baculovirus-infected insect cells significantly enhancing both IFN-γ production and lymphocyte proliferation; blocking p40 subunits with monoclonal antibodies substantially reduced this immune-enhancing effect, confirming p40's essential role. These findings establish the technical foundation for investigating equine IL-12's potential as an immunotherapeutic agent—whether as a treatment for equine malignancy and infection or as a vaccine adjuvant—though clinical translation will require further evaluation of optimal dosing, delivery routes and efficacy in naturally occurring disease.
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Practical Takeaways
- •This research establishes the foundation for developing species-specific equine IL-12 therapeutics, which may eventually offer new treatment options for equine cancer, inflammatory, and infectious diseases
- •The successful production of bioactive equine IL-12 through multiple expression systems provides tools for future investigation of therapeutic applications in horses
- •Clinical applications remain investigational and require further in vivo studies before practical implementation in equine practice
Key Findings
- •Equine IL-12 was successfully produced through expression of p35 and p40 subunits in mammalian and insect cells, as well as a single chain p35:p40 fusion polypeptide in mammalian cells
- •Conditioned medium from transfected cultures expressing equine IL-12 enhanced IFN-gamma production in equine lymph node-derived cells
- •Anti-p40 monoclonal antibody preincubation significantly decreased IFN-gamma induction capacity, confirming p40 involvement
- •Baculovirus-expressed p35 and p40 enhanced target cell IFN-gamma production and proliferation in vitro