Secretion of human interferon alpha 2b by Streptomyces lividans

Abstract.

Biologically active human interferon alpha 2b (HuIFNα-2b) was secreted into the culture medium by Streptomyces lividans transformed with recombinant plasmids coding for HuIFNα-2b fused to the Streptomyces exfoliatus M11 lipase A signal sequence. Levels were low, 15 or 100 ng/ml, depending on the plasmid used. Neither processed nor unprocessed HuIFNα-2b was detected in cell lysates of the transformants secreting the recombinant product. However, the secreted recombinant product was found to partially degrade when cultures reached the stationary phase by the action of an, as yet, unidentified mycelium-associated factor. Experimental evidence suggests that the degrading factor is related to mycelium-associated proteolytic activity.