Figure 2

Adjuvant promoted strong protective immune responses to S-OIV H1N1 virus. To realize the least immunization dose of S-OIV and H5N1 vaccine needed for mice to raise sufficient protective immune responses to A/California/7/2009 virus, mice (n = 7 to 8 per group) immunized with PBS, 0.001 μg, 0.01 μg, or 0.05 μg of vaccine in the presence or absence of adjuvant. Three weeks after the single immunization, mice sera were evaluated for (A) H1N1 IgG, (B) H5N1 IgG, and (C) H1N1 IgG1 and IgG2a, and (D) H5N1 IgG1 and IgG2a immune responses to A/California/7/2009 virus. The data represent the mean titers ± SD (error bars) of antibodies in each group of animals.