Mucosal delivery of adenovirus-based vaccine protects against Ebola virus infection in mice

Background. Mucosal vaccination can offer several advantages over conventional intramuscular immunization to protect against Ebola virus (EBOV) infection, such as immune protection at sites of viral entry into susceptible individuals, and can be administered using needle-free devices. Methods. The present study evaluated oral and nasal vaccination of mice with human adenovirus serotype 5 (Ad) expressing the Zaire ebolavirus glycoprotein (Ad-ZGP) in terms of their protection against and underlying immune responses to EBOV. Results. Similar to intramuscular administration, oral or nasal vaccination of mice with Ad-ZGP fully protected the mice against a lethal challenge with mouse-adapted EBOV. Both T and B cell responses developed in mice receiving oral or nasal vaccination in different body compartments, indicating qualitative improvement of the immune response after mucosal immunization, compared with intramuscular vaccination. Conclusions. Overall, the breadth of the immune response noted after nasal or oral immunization, including stimulation of CD8+ T cells or effector memory T cells from the gastrointestinal tract or the lungs, was superior to that noted after intramuscular administration of the vaccine. The present study showed that adenovirus-based vaccine is effective against EBOV infection in mice after oral and nasal immunization.