AFFINITY-PURIFIED DENGUE-2 VIRUS ENVELOPE GLYCOPROTEIN INDUCES NEUTRALIZING ANTIBODIES AND PROTECTIVE IMMUNITY IN MICE

We constructed a recombinant baculovirus which produces a dengue (DEN) -2 virus envelope (E) protein containing a six-histidine (H6) tag in p lace of the last 100 amino acids at its C-terminus. The recombinant pr otein was purified from the supernatant of baculovirus-infected Spodop tera frugiperda insect cell cultures to apparent homogeneity by cation -chelation chromatography (TALON(TM)) in which the H-6-tagged E-protei n was eluted under non-denaturing conditions with 100 mM imidazole at pH 8.0. Mice vaccinated with the purified E mixed with aluminium hydro xide adjuvant showed an immune response of IgM and IgG1, IgG2a and IgG 2b isotypes, and neutralizing antibodies, similar to that following im munization with purified inactivated DEN-2 virus. Moreover, mice that received the purified recombinant protein were significantly protected against 200 50% lethal dose of DEN-2 virus. This combination of affin ity purified H-6-tagged protein and adsorption onto a cationic carrier seems promising for the production of immunogenic particulate protein s, especially DEN protein for the four serotypes, and the development of a new generation of vaccines. (C) 1997 Elsevier Science Ltd.