Fig. 4.

The number of maternal immunizations correlate to the level of maternal antibodies and protection against lethal influenza challenge of the offspring. a Design; Adult female mice were vaccinated either 1×, 2× or 3× with Inflexal, or 3× mock immunized with PBS before and/or during mating. Offspring were vaccinated at 3 weeks of age with 0.01 μg Inflexal and subsequently challenged with H1N1 A/Netherlands/602/09 4 weeks post immunization. b The level and protection mediated by maternal antibodies correlate to the number of maternal immunizations; Adult female mice were vaccinated either 1×, 2× or 3× with Inflexal or PBS before and/or during mating. Offspring was immunized with 0.01 μg / HA and subsequently challenged with H1N1 A/Netherlands/602/09 at the age of 7 weeks. One day prior to challenge blood samples were analyzed for homologous recHA A/California/07/09 IgG binding titers. Statistical significance of recHA binding titers and survival percentage compared to the mock immunized group, *p < 0.05, *p < 0.01, ***p < 0.001