Differential expression and secretion of alpha I antitrypsin between direct DNA injection and implantation of transfected myoblast

Muscle can be used for systemic delivery of non-muscle proteins. In order t o investigate the relative effectiveness of direct DNA plasmid injection ve rsus implantation of genetically modified myogenic cell lines, we have used the human alpha 1 anti-trypsin (alpha 1AT) cDNA driven by either cytomegal ovirus (CMV) or the muscle creatine kinase 3.3 kb (MCK) promoter in immunod eficient mice. We demonstrate that the implantation of transfected myoblast s stably expressing the human alpha 1AT cDNA generates a more persistent pr oduction of alpha 1AT than does direct intramuscular injection of the same construct as plasmid DNA. Moreover immunohistological labelling of muscle s ections implanted with myoblasts show that the newly formed muscle fibres a re those containing the human protein.