Production of biologically active equine interleukin 12 through expression of p35, p40 and single chain IL-12 in mammalian and baculovirus expression systems.

This research article deals with the study of Interleukin-12 (IL-12) reproduction in horses, a process vital to the development of immune responses. The study seeks to determine the biological activity of the products derived from equine IL-12 and to analyze its expression as a p35/p40 fusion peptide, paralleling processes observed in several mammalian species.

Understanding Interleukin-12 and Its Function

• Interleukin-12 (IL-12) is a major factor for the development of cell-mediated immune responses. In layman’s terms, it is one of the proteins responsible for controlling and regulating our body’s defenses against foreign bodies and diseases.
• It is made up of two subunits, p35 and p40, which are linked through disulphide bonds. Hence, the production of IL-12 involves the expression of these constituent parts.

Objective and Method of the Study

• The primary purpose of this research was to decide on the biological activity of the products that came about as a result of the expression of equine IL-12 cDNA’s, p35 and p40.
• Researchers also aimed to figure out if equine IL-12 (that is, the IL-12 protein specifically from horses), could be expressed as a fusion polypeptide of p35/p40, analogous to what has been seen in other mammals.
• In order to carry out this study, the p35 and p40 subunits were expressed in both mammalian cells and insect cells along with a p35:p40 fusion polypeptide in mammalian cells.

Results and Implications of the Study

• Through the study, scientists managed to produce equine IL-12. Conditioned medium (medium recovered from cultures) that was transfected with constructs that encoded equine p35 and p40 subunits led to an increase in IFN-gamma production in cells from horse lymph nodes. IFN-gamma is another protein responsible for regulation and activation of the immune response, and is beneficial in combating diseases.
• The capacity to induce IFN-gamma was significantly reduced after this medium was treated with an anti-p40 monoclonal antibody.
• The medium recovered from baculovirus (a type of virus that affects insects) infected cultures expressing p35 and p40 also boosted the production and proliferation of the target cell’s IFN-gamma.
• Previous studies have shown that IL-12 has therapeutic benefits in cancer, infectious diseases, and inflammation and also serves as an enhancer or ‘adjuvant’ in preventive treatments in mice and other animals.
• The production of a bioactive and horse-specific IL-12 is the first step to investigating its potential benefits and applications in equine diseases.