Production of human interferon in E. coli under lac and tryplac promoter control

Production of two human 2',5'-oligoadenylate synthetase enzymes in Escherichia coli

We have isolated and characterized two types of cDNA clones corresponding to interferon (IFN)-induced 1.6- and 1.8-kb mRNAs, as encoding two different forms of the 2',5'-oligoadenylate (2'-5')A synthetase enzyme. Direct expression of the two cDNAs was obtained in Escherichia coli under the control of a trp-lac hybrid promoter strongly inducible in E. coli by IPTG. Bacterial extracts were tested for 2'-5'A synthetase activity after adsorption to immobilized poly(I).poly(C) or in solution. With either one of the cDNA constructions, IPTG induced 2'-5'A synthetase activity in the bacteria to levels 10 times higher per microgram of protein than those in SV80 cells treated by 500 U/ml of IFN-beta1 for 24 h. Both bacterially produced enzymes bind to double-stranded (ds)RNA and are maximally active at 100 micrograms/ml of poly(I).poly(C). Both enzymes synthesized similar 2'-5'(Ap)nA oligomers of 2 to 8 residues in length. Antibodies against a synthetic peptide common to the two enzymes were used to characterize the bacterial products on immunoblots and confirmed that the 1.6-kb RNA produces a 39-kD protein, whereas the 1.8-kb RNA encodes a 45- to 46-kD protein. The E. coli enzyme coded by the 1.6-kb mRNA was purified to nearly homogeneity. When immobilized on poly(I).poly(C) agarose, the enzyme produces, per milliliter of poly(I).poly(C), 10(3) times more 2'-5'(Ap)nA oligomer than the most active cellular extracts. Moreover, the immobilized enzyme remains stable for several months at 4 degrees C.

Recombinant interferon alpha-C for advanced hairy cell leukemia. An Israeli multicenter study

Thirteen patients with advanced hairy cell leukemia were treated with a new subspecies of interferon (IFN): recombinant IFN (rIFN)-alpha-C. The timing of the peripheral hematologic remission of individual blood elements was similar to that reported for other interferons, and 60% of patients attained a complete peripheral hematologic remission at 9 months. Two patients relapsed despite a good initial response to IFN. No anti-IFN antibodies could be detected in their sera. In vitro studies of colony formation from the peripheral blood of all responding patients showed that rIFN-alpha-C did not inhibit the growth of colonies but favorably affected the maturation of their elements towards monocytes, granulocytes, and erythroid elements. The relapsing patient examined initially experienced a similar beneficial in vitro response which paralleled his in vivo improvement. During relapse, rIFN-alpha-C inhibited both the colony formation and the myelomonocytic differentiation in the in vitro cultures. These findings may suggest that the acquired resistance to IFN in our patient could be due either to an acquired stem cell maturation arrest in response to IFN or to emergence of a new clone indifferent to IFN-alpha-C differentiation effect.