FURTHER PROTECTION AGAINST ANTIGENIC DRIFT OF INFLUENZA-VIRUS IN A FERRET MODEL BY DNA VACCINATION

Previously we showed that immunization of ferrets with DNA encoding th e hemagglutinin (HA), nucleoprotein (NP), and matrix protein (M1) of i nfluenza virus induced protective immune responses. A DNA vaccine enco ding HA (from a 1991 strain), NP and M1 (from a 1989 strain) protected ferrets better against challenge with the antigenic drift variant A/G eorgia/03/93 than did the inactivated vaccine from the 1992-93 influen za season. Here we report that the same DNA vaccine protected ferrets against a second, further divergent, drift variant (A/Johannesburg/33/ 94). Furthermore, the extent of protection provided by the DNA vaccine was equivalent to the homologous protection provided by an inactivate d vaccine that exactly matched the challenge strain. (C) 1997 Elsevier Science Ltd.