Erythropoietin gene is immunogenic. In the present study the recombinant plasmid pVAX1.epo.hu transfected HeLa cells expressed protein which was confirmed by immunoperoxidase test, SDS-PAGE and western blotting. The cells were found to express the protein with development of purple color precipitate in Immunoperoxidase test. Intense purple coloration of cells was observed in HeLa cells transfected with pVAX1.epo.hu. The vector alone and untransfected healthy cells failed to show any coloration confirmed no expression of proteins. By SDS-PAGE and western blotting, the expressed erythropoietin (34 kDa) was confirmed. The in vivo immunological response was studied in mice.