This set of models demonstrates the region-specific properties of antibodies generated from different flu vaccines. The pink hemagglutinin receptor is H1, and the blue receptor is H3. The colored areas on the outside of the receptors indicate the antibody binding sites. The yellow antibody (FI6) will bind at the stem region of receptors on both flu strains. The head antibodies are specific to each strain, due to the higher rate of mutations at the head region of the receptor.

H1 structure created from PDB entry 5UGY, and H3 is created from 4WE8.