Improvement of human interferon alpha secretion by Lactococcus lactis.

To improve the secretion and expression of human interferon alpha 2b (IFN) in Lactococcus lactis, a synthetic pro-peptide, LEISSTCDA (LEISS), was fused to the N-terminus of IFN. This gave a higher secretion efficiency (12% vs. 5%) and yield (approximately 2.8-fold) of IFN. The signal peptide, SP(SlpA) (SlpA, an S-layer protein of Lactobacillus brevis), was also tested to secrete IFN instead of SP(Usp45) (Usp45, the main secreted protein in L. lactis). This gave increased IFN secretion (approximately 3-fold) but lower total production. All the recombinant IFN had appropriate bioactivities in an antiviral assay.