IgG antibody responses with low dose (0.1 µg) of VLPs.

IgG serum antibodies specific to A/California/04/2009 influenza virus were determined at week 1, 3, 5 in the group of mice immunized with low dose 1 µg of VLPs. Titers are expressed as the highest dilution of serum having a mean optical density at 450 nm greater than the mean plus 2 standard deviations of naive serum samples. Significant higher IgG titers against new H1N1 were detected at week 3 compared to week 1 (P<0.01); and at week 5 compared to week 3 (P<0.001).