Figure 4.

Characterization of anti-NA antibody responses in sera from vaccinated samples. Pre-challenge samples (after the 2nd vaccination) were obtained from the different groups of mice. Antibodies in serum able to bind to a recombinant tetrameric Mich15-VASP protein (A) or to the A/Michigan/45/2015 H1N1 virus (B) were measured by ELISA. The ability of serum antibodies to inhibit the neuraminidase enzymatic activity was assessed using the A/Michigan/45/2015 virus (C). The 50% inhibitory concentration (IC₅₀) for each pool of serum samples is shown (D).