CROSS-PROTECTION OF MICE AGAINST A GLOBAL SPECTRUM OF RABIES VIRUS VARIANTS

Rabies, a continuing worldwide problem, kills tens of thousands of people and millions of animals each year. The problem is most severe in developing countries, where cell culture-derived vaccines are unaffordable and the available nervous tissue-derived vaccines are often of questionable immunogenicity and may produce neurological complications. To determine the feasibility of developing a vaccine with worldwide applicability, we investigated whether recombinant vaccinia viruses expressing either the glycoprotein (G), the nucleoprotein (N), or both the G and N (GN) of the challenge virus strain (CVS) of rabies virus would cross protect mice against 17 rabies virus isolates representing the spectrum of rabies virus variants found worldwide. The results were compared with the commercially available human diploid cell vaccine (HDVC). Among mice injected with any of the 17 viruses, greater than or equal to 95% were protected by vaccination with recombinant viruses expressing G or GN, and greater than or equal to 85% of the mice were protected by the HDCV. The recombinant virus expressing N was less protective, protecting against only 11 of the 17 viruses. Antibody prepared against the G of the strains used in the vaccines neutralized all 17 viruses, and sera from mice infected with any one virus variant cross-neutralized all of the other viruses, Thus, no antigenic differences that would potentiate vaccine failures were identified. These studies suggest that a single rabies virus strain or its G would protect globally against wild-type rabies viruses.