Preparative in vitro synthesis of bioactive human interleukin-2 in a continuous flow translation system.

Recombinant human interleukin-2 has been synthesized in vitro in a continuous flow translation system based on the wheat germ extract. In the course of translation of mRNA the interleukin-2 becomes aggregated due to the adsorption of this protein onto the ribonucleoprotein complex. This process correlates with the cessation of translation that is usually observed in 25-30 min. This can be prevented by the use of a flow system that allows continuous removal of the synthesized protein and maintains a steady concentration of all the necessary components. This approach permitted a yield of 1,500 protein molecules per mRNA molecule. The interleukin obtained promotes the proliferation of the interleukin-2-dependent CTLL-2 cell line. The biological activity of interleukin-2 not subjected to oxidative refolding was 10(5) units per milligram of protein.