Human adenovirus type 5 vectors expressing rabies glycoprotein.

The prevalence of wildlife rabies throughout the world and the continued spread of this disease in North America highlights the need for oral vaccines which may be used safely and effectively to vaccinate a number of species that are reservoirs or vectors of rabies. We have previously shown that AdRG1, a replication competent recombinant human adenovirus type 5 (Ad5) expressing a rabies glycoprotein (RG), can induce immunity to rabies in rodent, canine, and skunk model systems. To improve the Ad5 vector system as a potential oral vaccine, we have constructed additional Ad5 recombinant vectors and compared RG expression in cell culture and immunogenicity in animals. Two new replication competent vectors are compared. AdRG1.3, which carries RG with accompanying SV40 poly A addition sequences within an E3 deletion, and AdRG4, which has RG in the E3 deletion but under the control of an exogenous Ad2 major late promoter, both express higher levels of RG in permissive cell culture than did AdRG1 and both elicit high levels of serum anti-rabies antibodies by parenteral or oral routes in animals. AdRG1.3 may be a more effective vaccine vector in species which are non-permissive for the replication of human Ad5.