A cationic lipid/DNA adjuvant (JVRS-100) dramatically improves the immunogenicity and protection after immunization of elderly rhesus monkeys with a licensed inactivated seasonal influenza vaccine (Fluzone®). (52.21)

Abstract

Abstract To determine if an adjuvant can improve the efficacy of an inactivated seasonal influenza vaccine in immunosenescent primates, elderly rhesus monkeys were vaccinated with Fluzone. In a subset of the animals, Fluzone was mixed with a cationic lipid/DNA adjuvant (JVRS-100). After influenza A/Memphis/7/2001 (H1N1) challenge, the 9 monkeys vaccinated with Fluzone alone had no detectable reduction in viral shedding in tracheobronchial secretions relative to the 9 non-immunized control animals. However, the 9 animals immunized with JVRS-100 and Fluzone had a 4-fold lower peak level of virus in tracheobronchial secretions compared to unimmunized control animals (p<0.05) and Fluzone-only immunized monkeys (p<0.01). The cumulative level of viral replication as determined by an area under curve analysis were 7-8 fold lower (p<0.05) in animals immunized with JVRS-100 and Fluzone compared to both Fluzone-only and non-immunized monkeys. Moreover, monkeys immunized with JVRS-100 and Fluzone had no evidence of fever or weight loss whereas both signs of illness were evident in the non-immunized and Fluzone-only animals in the first week after challenge. Thus, addition of JVRS-100 to Fluzone generates protective immunity that blunts virus replication and eliminates the clinical signs seen in the elderly monkeys that are not protected by Fluzone alone.