A DNA delivery system using sea urchin sperm specific histone H1 for DNA vaccine development and gene therapy

A novel sea urchin sperm histone H1 (Sp H1) has been formulated with plasmid DNA (pDNA) to create polycationic protein-based gene delivery systems. The carrier protein is used to condense plasmids into complexes to improve the intracellular delivery of plasmid DNA. The Sp H1-based gene delivery systems were tested for transfection efficiency in a variety of cell lines, using gene expression systems containing the EGFP (Enhanced Green Fluorescent Protein) and Hepatitis B virus (HBV) surface antigen (HBsAg) genes. The Sp H1 is easily purified in large-scale from the source using inexpensive simplified processing in our laboratory.;Our results indicated that recombinant Sp H1 was able to deliver plasmid DNA in all cells tested. Transfection data demonstrate a correlation between in vitro transfection efficiency and the combination of several physical properties of the Sp H1-pDNA complexes, including (1) DNA dose (2) Sp H1/pDNA mass ratio (3) the molecular nature of the protein. Transfection data on pDNA complexes utilizing the Sp H1 protein formulated in an optimal gene delivery system show an increase in gene expression levels. Comparative analysis based on pHBsAg gene expression revealed that the transfection efficiency of Sp H1 was better than wheat germ-derived histones; comparable to, or better than, liposome-based systems.;We tested the effect of Sp H1-pDNA encapsulated systems for in vitro delivery of plasmid DNA to antigen-presenting cells for enhanced immune responses to the encoded protein. To achieve this aim, the optimal Sp H1-pDNA formulation embedded in albumin microsphere was prepared using a spray drying technique. Encapsulating Sp H1-complexed pDNA into albumin microspheres further increased the stability of Sp H1-complexed pDNA with enhanced gene expression profiles in antigen presenting cell line, RAW 264.7. Sp H1-pDNA albumin microspheres further protected the pDNA from physical stress and heparin treatment when compared with free pDNA. Our novel gene delivery system represents an improvement for its applicability in vaccine development and gene therapy.