Figure 4

Hemagglutination inhibition (HI) titer scores against vaccine strains and antigenically distinct influenza A virus strains. Titers were determined 4 weeks after the second and third vaccination (PV 2 and 3). The colors of the test viruses are based on the HA lineage. Blue, classical swine H1 (1A); orange, human-like H1 (1B); green, avian-like H1 (1C); dark red, European human-like H3 (3.1970.1); magenta, novel human-like H3 (3.2010.1). The HA clade is mentioned between brackets. Antibody titers were given a score from 0 to 4.5; the scoring system is explained below the Figure. The scores are means of the scores of the individual pigs of each group; they are converted to a heatmap. The % cross-reactivity indicates the percentage of virus strains against which an HI titer score ≥ 2.0 was achieved. See Figure 1 for full names of IAVs and the vaccine names.