Figure 2From: Serological characterization of guinea pigs infected with H3N2 human influenza or immunized with hemagglutinin proteinAnalysis of serum pools from immunized guinea pigs. Sera pools were tested for antibodies that bind to non-denatured full-length HA protein by ELISA and are denoted with solid lines. Sera pools were also tested for antiviral activity by HI, shown with dashed lines. Negative control animals in Group 1 were discontinued after 13 weeks. Arrows along X-axis indicate immunization boost dates. Error bars for the extinction titers are shown, but due to their small size, are not visible.Back to article page