CONSTRUCTION AND EXPRESSION IN ESCHERICHIA-COLI-CELLS OF THE FUSION PROTEIN OF DIPHTHERIA-TOXIN AND HUMAN INTERLEUKIN-2

Plasmids were constructed that carry out the synthesis of the human di phtheria toxin (DT) and human interleukin 2 (IL-2) fusion protein unde r the DT gene promoter, and differ from one another in the size of the DT gene. The base sequence in the seam area of the DT and IL-2 genes was determined, and conservation of the reading frame was shown. In Es cherichia coli cell lysates bearing recombinant plasmids, the presence of fusion proteins with molecular weights of 68 and 72 kDa, containin g DT and IL-2 antigenic determinants, was shown. The fusion protein wa s partially purified by affinity chromatography. In order to increase expression, the structural gene of the fusion protein DTIL2 was put un der the control of a number of strong inducible promoters (lac, tac, P (R)). Immunoenzyme assay showed that under the control of the tac prom oter.the level of DTIL2 polypeptide synthesis increased at least 100-f old compared with the initial. The application of fusion proteins for treating human diseases is discussed.