Assessment of DNA vaccine potential for juvenile Japanese flounder Paralichthys olivaceus, through the introduction of reporter genes by particle bombardment and histopathology

Genetic immunisation potential, following DNA bombardment for juvenile Japa nese flounder, Paralichthys olivaceus was examined. GFP plasmids bombarded at two pressures, 150 and 300psi were sampled at 1, 7, 14 and 28 days, grea ter immunofluorescence was observed at the higher bombardment pressure. His topathology, at 3 h post bombardment showed considerable damage to fish epi thelial and dermal tissues when bombarded at pressures greater than 200 psi , with many DNA-coated gold particles present. At 150psi there was little p athology and no DNA-coated particles. Histopathology, up to 28 days again s howed little pathology at 150 psi with few DNA-coated particles, whereas at 300 psi there was significant pathology observed with many DNA-coaled part icles seen in conjunction with the cytoplasm of inflammatory cells. By day 28 epithelial coverage was observed with tissue damage restricted to the de rmal layer. Chloramphenicol acetyltransferase (CAT) assay showed long term and stable expression of the CAT protein from day 1 to day 60. The transcri ption activity of two promoters; pCMV-CAT and pSV2-CAT showed greater activ ity in the former. It was concluded that DNA vaccination potential for juve nile flounder is a viable option. (C) 2000 Elsevier Science Ltd. All rights reserved.