Abstract: The discovery of simple, nontoxic, and pharmaceutically defined methods for genetic modification of cells and tissues would enable development of a variety of molecular medicines. “Free”, ‘direct’, or ‘naked’ polynucleotide administration is a simple, apparently safe, and pharmaceutically defined polynucleotide delivery method. Murine, macaque, and clinical human experiments have demonstrated transfection of various tissues, such as respiratory tissues, after direct application of ‘free’ polynucleotide. However, direct DNA transfection is relatively inefficient in comparison to many transduction systems. The invention herein is directed to transfection enhancing agents which augment the transfection activity of ‘free’ polynucleotide, thereby facilitating the development of simple and safe alternatives to tissue transfection, more particularly respiratory tissue transfection.

Abstract: The invention consists of a method for inducing production of a mucosal immune response in a host by administration of an antigen-encoding polynucleotide preparation, comprising DNA or RNA encoding an antigenic epitope to a mucosal inductor site in the mucosal tissue of the host. Naked DNA may be administered directly to mucosa, for instance in saline drops, or in a recombinant gene expression vector. Preferably, the recombinant gene expression vectors are not capable of replication or dessimination. The invention also includes the use of live viral vaccines wherein the viruses include immunostimulatory polynucleotides of the invention. According to a preferred method of the invention, a target protein antigen is administered through its expression by a recombinant gene expression vector.