The immune response to a polyoma virus replicon-based DNA vaccine

DNA vaccination has proven to be effective against a number of tumours and microbial diseases. As DNA vaccines are unable to replicate, plasmid copy n umber per cell is dependent on in vivo transfection efficiency, which is us ually quite low. Consequently, immune responses generated are likely to be sub-optimal due to low antigen expression levels in transfected cells. Duri ng this study, replicating: DNA vaccines delivered intra-epidermally by gen e gun, were assessed for their ability to more efficiently generate immune responses in mice. The data demonstrate that, using a polyoma virus-based s ystem of replication, 10-fold less DNA expressing the haemagglutinin gene o f influenza virus, was required to stimulate a humoral immune response, com pared to an equivalent non-replicating vaccine. This observation suggests t hat the use of replicating DNA vaccines in some delivery systems may enhanc e the effectiveness of immune responses. (C) 2000 Elsevier Science Ltd. All rights reserved.