Expression of bioactive porcine interferon-gamma by recombinant Lactococcus lactis

Lactococcus lactis is an immunomodulator and candidate live mucosal delivery vehicle for vaccine antigens and for biologically active molecules, including immunoregulatory cytokines such as interferon-gamma (IFN-γ). To provide a tool for investigating downregulation of allergic predisposition of pigs to experimental food allergy, porcine IFN-γ was cloned and expressed as a fusion protein with the usp45 secretion signal. Immunoblot analysis with polyclonal anti-pIFN-γ-antibody demonstrated that the recombinant porcine IFN-γ (rpIFN-γ) protein was expressed in the L. lactis transformants as a secreted product. Activity of rpIFN-γ was confirmed by ability to upregulate class II major histocompatibility complex (MHC) on cells of the porcine monocytic cell line 3D4/31. The L. lactis producing biologically active rpIFN-γ will be used to investigate its possible ability to modulate the allergic immune response phenotype of pigs.