Enhancement of the immune response in rabbits to a malaria DNA vaccine by immunization with a needle-free jet device

We compared the needle free jet device device Biojector (TM) with syringe/needle as a method to administer a DNA vaccine encoding the Plasmodium falciparum circumsporozoite protein (PfCSP) in albino rabbits. A group of three rabbits was injected by the intramuscular (IM) route using a syringe/needle combination, a second group EM with the Biojector (TM) device and a third group both IM and intradermal (ID) using the Biojector (TM). When animals were immunized with the Bicjector (TM) or IM/ID as compared to the syringe/needle IM, we observed 10- and 50-fold greater antibody titers, as measured by enzyme immunoassay (EIA) and indirect fluorescence antibody test (IFAT), respectively. We also observed that the Biojector (TM) conferred a greater ability to prime the immune system as compared with the needle. The subsequent boosting of all animals with a recombinant canary pox virus (ALVAC) expressing PfCSP induced significantly hi g her titers in both Biojector (TM) groups of rabbits as compared with the needle and naive animals. These results provided the foundation for a clinical trial using the same regime. Published by Elsevier Science Ltd.