A
rabies DNA vaccine consisting of
plasmid DNA expressing the
rabies virus surface glycoprotein was injected (im) twice at two week interval to outbred
swiss mice or
Bonnet monkeys (
Macaca radiata ) and the levels of
rabies virus neutralizing antibody (VNA) titres were examined over a one year period. In
mice , the VNA titre was maintained above the minimum protective level (0.5 I.U./ml) up to 10 months after primary
immunization , while in
monkeys , the titre dropped below the protective level by 6 months. An anamnestic B
cell response was seen in both
mice and
monkeys following the
administration of a booster
dose , 10 and 6 months after the primary
immunization , respectively. These results indicate that im
injection of
rabies DNA vaccine induces VNA in nonhuman
primates and
mice unlike intradermal (
id )
immunization , which was shown to induce VNA only in
mice but not in
monkeys . This is the first
report on the induction of VNA in nonhuman
primates by im inoculation of
rabies DNA vaccine .