Role Of Host And Viral Factors In Resistance To Rabies V

Niaid Extramural Activities

Investigators

Linked publications & trials

Abstract

1) Rabies DNA gene gun vaccinations in ear pinnae or above the axillary and inguinal lymph nodes of Macaca fascicularis monkeys elicited higher levels of neutralizing antibody than did intradermal vaccinations in ear pinnae. Concurrent gene gun booster vaccinations in the ear pinnae and above the lymph nodes 3 days after primary vaccination accelerated the induction of neutralizing antibody. Thus, an extended "rest period" between DNA vaccinations is not necessary to accelerate and to augment the neutralizing antibody response of non-human primates. 2)Post-exposure vaccination of monkeys with DNA or the human diploid cell vaccine, in combination with a one-time treatment of human rabies immune globulin six hours after injection of rabies virus protected 50% and 75% of the monkeys respectively, as compared to 75% mortality of the monkey controls.3)Post-exposure rabies DNA vaccination, in combination with a non-protective dose of anti-rabies immune serum, protects mice against rabies virus. Thus, post-exposure therapy, substituting a DNA vaccine for the commercial human diploid cell vaccine, does not compromise protection against rabies virus. This study is the first, to our knowledge, to demonstrate post-exposure protection in a murine system against a viral infection with a DNA vaccine. 4)Dogs vaccinated i.d. in the ear pinna with a rabies DNA vaccine produce elevated and durable neutralizing antibody responses. In contrast, vaccination of dogs in quadriceps muscle, gene gun vaccination in ear pinnae or i.d. vaccination in the neck elicit minimal or undetectable levels of neutralizing antibody. 5)Mice passively administered sera from dogs vaccinated with a rabies DNA vaccine are protected against rabies virus challenge. 6)Cattle immunized i.d. with a rabies DNA vaccine in the caudal tail-fold and the ear pinna continue to produce neutralizing antibody 2 years after vaccination. 7)The exchange of different rabies virus glycoprotein genes between different plasmids results in a more protective DNA vaccine if the vaccines are injected intramuscularly. Differences in antibody titers or protection of mice with the different vaccines are not apparent after intradermal or gene gun vaccinations.8) Control plasmids (not expressing a rabies virus glycoprotein gene) protect mice against rabies virus if administered via the gene gun. Intradermal or intramuscular vaccinations with the control plasmids did not protect the mice.9)Persistent infectious virus and/or rabies virus genome is present in mice 26-450 days after virus injection. Virus and/or genome are detected primarily in bone marrow, injected muscle and the brain/spinal cord.