Cloning of porcine interleukin (IL)-12 receptor β2 (IL-12Rβ2) gene and its application to a rapid biological assay for human/porcine IL-12

Porcine IL-12Rβ2 gene was cloned from mRNA preparation of mitogen-activated peripheral blood mononuclear cells (PBMCs), and its complete nucleotide sequence was determined. To confirm the biological function, the entire open reading frame (ORF) was re-cloned into a mammalian expression vector, pcDNA3.1/Zeo(+), at the downstream of CMV promoter, and introduced to a Th1-like human lymphoma cell line, Jurkat E6-1. Antibiotic-resistant cells retaining the expression construct were selected then, isolated by the limiting dilution method. An established clone (10B10) constitutively expressed chimeric IL-12Rs composed of intrinsic (human) β1 and extrinsic (porcine) β2 subunits, and produced interferon (IFN)-γ in response to IL-12 of both species with optimal PHA/PMA stimulation. The production of IFN-γ was observed as early as 42 h after culture and appeared to be dose-dependent within the range between 20 and 2000 pg/ml. Thus, this clone not only reacts with IL-12 of both species but also provides a useful tool for quick and sensitive detection of IL-12 bioactivity.