Intranasal Administration of Adjuvant-Combined Vaccine Protects Monkeys From Challenge With the Highly Pathogenic Influenza A H5N1 Virus

The effectiveness in cynomolgus macaques of intranasal administration of an influenza A H5N1 pre-pandemic vaccine combined with synthetic double-stranded RNA (polyl/polyC12U) as an adjuvant was examined. The monkeys were immunized with the adjuvant-combined vaccine on weeks 0, 3, and 5, and challenged with the homologous virus 2 weeks after the third immunization. After the second immunization, the immunization induced vaccine-specific salivary IgA and serum IgG antibodies, as detected by ELISA. The serum IgG antibodies present 2 weeks after the third immunization not only had high neutralizing activity against the homologous virus, they also neutralized significantly heterologous influenza A H5N1 viruses. The vaccinated animals were protected completely from the challenge infection with the homologous virus. These results suggest that intranasal immunization with the Double stranded RNA-combined influenza A H5N1 vaccine induce mucosa! IgA and serum IgG antibodies which could protect humans from homologous influenza A H5N1 viruses which have a pandemic potential. J. Med. Virol. 82:1754-1761, 2010. (C) 2010 Wiley-Liss, Inc.