1) A/WySnJ mice have a single, autosomal, co-dominately expressed gene defect, Bcmd, which results in a severe peripheral B-lymphocyte deficiency. B lymphocyte lymphopoesis is normal, but the developmental defect disables IgG-secreting B-lymphocyte development. A/WySnJ mice vaccinated with the human diploid cell vaccine (HDCV),the vaccine used as the benchmark vaccine for rabies vaccine efficiency,do not produce neutralizing antibody and are not protected against rabies virus challenge.HIV-infected individuals and individuals udergoing treatment with immunosuppressive drugs have impaired neutralizing aqntibody responses after pre- and post- exposure vaccination with HDCV. A/WySnJ mice vaccinated with vaccinia recombinant vaccines expressing the rabies virus glycoprotein (G) or co-expressing the G and the rabies virus nucleoprotein (N) produce high levels of neutralizing antibody and are protected against rabies virus challenge.Thus,the Bcmd mutation of the B-lymphocyte deficient A/WySnJ mice was overcome by vaccination with live recombinant viruses. The recombinant vaccines co-expressing G and N, or N only, are equally effective in protecting A/WySnJ mice. Since N is known to be responsible for neurological disorders associated with rabies vaccination, there is no benefit to include N with G in a recombinant rabies vaccine. 2) The HDCV and other cell culture vaccines are expensive and not always available in developing countries. Vaccination with remaining doses within a vial of such vaccines after they have been reconstituted and stored at 4 degrees centigrade (C)would save dollars and provide additional doses of the vaccine. HDCV reconstituted and held at 4 degrees C for over one year is as effective as freshly reconstituted HDCV in eliciting neutralizing antibody and protectiing mice against rabies virus challenge. Thus, the remaining doses of the reconstituted vaccine could be used and need not be discarded.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 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 neutralizing antibody that remain in the protective range for more than 6 months.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 in the ear pinnae with a rabies DNA vaccine are protected against rabies virus challenge.6)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.7) Persistent infectious virus and/or rabies virus genome is present in mice 26-500 days after virus injection. Virus and/or genome are detected primarily in bone marrow, injected muscle and the brain/spinal cord.8) Taq-Man analysis of tissues from rabies virus injected mice has increased the sensitivity at least 100-fold for detecting rabies virus genome in persistently-infected mice. Rabies virus genome is persistent in tissues of 40% of immunodeficient mice infected with an avirulent rabies virus.9)Contrary to dogma, there is viremia in rabies-injected mice.
