Expression and activity of a recombinant chimeric protein composed of pokeweed antiviral protein and of human interleukin‐2

Abstract

The pokeweed antiviral protein (PAP) has already been used to chemically construct immunotoxins. Here we tested the recombinant approach for the production of PAP-containing cytotoxic fusion-proteins. A cDNA encoding a mutated PAP (PAP9), which is expressed at high levels in bacteria, was fused to human interleukin-2 (IL-2) cDNA. The resulting PAP9-IL-2 protein was as active as the free PAP9 in inhibiting an eukaryotic cell-free translation system. Only the chimeric protein desaminated the 28S rRNA and inhibited translation of the CTLL-2 cell line which expresses the IL-2 receptor. These results show that PAP is a suitable toxin for the production of recombinant immunotoxins.