Molecular cloning and expression of cynomolgus monkey interleukin-2 cDNA by the recombinant baculovirus system

The cDNA encoding interleukin-2 (IL-2) of cynomolgus monkey was molecularly cloned from concanavalin-A-stimulated peripheral lymphocyte cDNA by the reverse transcription-polymerase chain reaction method. Cynomolgus monkey IL-2 cDNA displays a high degree of homology with the human equivalent both at nucleic acid (98%) and amino acid (96%) sequence levels, although having only one additional amino acid residue. Recombinant monkey IL-2 secreted by insect cells infected with the recombinant baculovirus migrated as two distinct bands with 15 and 18 kD corresponding to mature and precursor IL-2 molecules, respectively, which were revealed to cross-react with anti-human IL-2 polyclonal antibody in Western blot analysis. This monkey IL-2 exhibited high biological activity up to an order of 10(6) U/ml as assessed by an IL-2-dependent cell proliferation assay and was shown to be neutralized by anti-human IL-2 antibody.