INOCULATION OF PLASMIDS EXPRESSING THE DENGUE-2 ENVELOPE GENE ELICIT NEUTRALIZING ANTIBODIES IN MICE

To develop a nucleic acid vaccine against dengue type-2 virus, the Pre M and 92% of the envelope (E) genes were cloned into different eukaryo tic plasmid expression vectors (pkCMVintPolyli and pVR1012). The resul tant plasmid constructs (pD2ME and P1012D2ME) properly expressed the t runcated E protein in vitro as evidenced by the expected protein size on SDS-PAGE and the ability, of the protein to be recognized by monocl onal antibodies directed against conformational epitopes. Three-week-o ld BALB/c mice were given intradermal inoculations of each construct. Plasmid expression vectors without dengue genes were used as controls. One hundred percent of the mice that received the pD2ME and p1012D2ME constructs developed anti-dengue antibodies. These antibodies were sh own to neutralize dengue type-2 virus in vitro. This is the first demo nstration of the use of nucleic acid inoculation in the development of potential dengue virus vaccines. (C) 1997 Published by Elsevier Scien ce Ltd.