Molecular cloning, expression and antiviral activity of porcine interleukin-29 (poIL-29)

Human interleukin-29 (IL-29) is a recently discovered cytokine displaying antiviral activity against a broad spectrum of viruses, designated as interferon (IFN)-λ1. We here report the molecular cloning, expression and antiviral activity of porcine IL-29 (poIL-29). The full-length poIL-29 cDNA sequence encoded 191 amino acids with a 19 amino acid signal peptide. Sequence alignments showed that poIL-29 had amino acid sequence similarity to wolf (76%), bear (75%), horse (75%), orangutan (73%), human (72%), cat (72%) and dog (70%) IL-29. The poIL-29 without signal anchor sequence was efficiently expressed as a 6×HIS fusion protein in Escherichia coli and the antiviral activity of the purified recombinant protein was 1.8 × 103 U/mg protein. The purified recombinant poIL-29 also exhibited significant antiviral effects against porcine reproductive and respiratory syndrome virus and pseudorabies virus in a dose-dependent manner, suggesting that poIL-29 is a potential antiviral agent against swine infectious diseases.