The Ebola vaccine that proved effective in a trial of more than 4,000 people in Guinea seems to work by rapidly triggering one arm of the immune system to hold back the virus while the body ramps up antibody production, according to a study in monkeys.
Heinz Feldmann of the National Institute of Allergy and Infectious Diseases in Hamilton, Montana, and his colleagues tested the VSV-EBOV vaccine, which was designed to fight the 2014 West African outbreak strain of Ebola virus. The team immunized 15 rhesus macaques (Macaca mulatta) and then infected them with the virus. All but one of the vaccinated animals survived, whereas all unimmunized animals died about a week after infection.
Analysis of the surviving animals' blood showed that the vaccine triggered the innate immune system to keep viral replication in check during the first days of infection, giving the rest of the immune system time to churn out Ebola-specific antibodies.
Science http://doi.org/6p9 (2015)