Particle-mediated DNA immunization of cattle confers long-lasting immunityagainst bovine herpesvirus-1

Particle-mediated delivery was used as a method to vaccinate ruminants with a DNA vaccine. The optimal conditions for gene gun-based delivery of gold particles into the epidermal layer of the skin were determined. After deliv ery of the gold particles, an inflammatory response was observed. This resp onse occurred regardless of the presence of plasmid and therefore was a res ult of the physical disturbance of the skin by the gold particles. To ident ify transfected cells, a plasmid expressing a green fluorescent protein was delivered into the skin. Fluorescent cells were located primarily in the o utermost layers of the epidermis and outside the core of gold particles dep osited by the gene gun. Cattle were immunized by gene gun with a plasmid ex pressing a truncated, secreted form of bovine herpesvirus-1 glycoprotein D. Serum antibody responses, antigen-specific proliferation, and interferon-g amma secretion by peripheral blood lymphocytes were demonstrated. These imm une responses were found to be of long duration and sufficient magnitude to protect cattle against challenge with bovine herpesvirus-1, which demonstr ates the efficacy of gene gun-based delivery of DNA vaccines to target spec ies, (C) 1999 Academic Press.