Protection against respiratory syncytial virus by inactivated influenza virus carrying a fusion protein neutralizing epitope in a chimeric hemagglutinin

In an approach to deliver respiratory syncytial virus (RSV) neutralizing epitopes without RSV-specific T cell antigens, we genetically engineered chimeric influenza virus expressing RSV F262 -276 neutralizing epitopes in the globular head domain as a chimeric hemagglutinin (HA) protein. Intramuscular immunization of mice with formalin-inactivated recombinant chimeric influenza/RSV F262 -276 induced IgG2a antibodies dominantly specific for RSV F protein. After RSV challenge, inactivated chimeric influenza/RSV F262 -276 immune mice controlled lung viral loads and did not cause RSV-specific T cell responses and vaccine-enhanced pulmonary disease compared to formalin-inactivated RSV-immunized mice.174