Figure 4.

Repertoire of H7-specific antibodies (Abs) in H7N7 live attenuated influenza vaccine (LAIV)–primed, H2N3 LAIV–primed, and unprimed cohorts before and after H7N7 inactivated influenza vaccination. A, Number of bound phages after H7 (NL/03) gene-fragment phage display library (GFPDL) affinity selection by pooled sera from each cohort on days 0 and 14. B, Schematic alignment of the peptides recognized by pooled sera on days 0 and 14. Peptides were identified by panning with an H7 (NL/03) GFPDL and were aligned to the H7 HA translated sequence. The amino acid designation is based on the HA protein sequence (Supplementary Figure 1). Bars indicate identified inserts in HA1 (red bars) and HA2 (blue bars). The thickness of each bar represents the frequency of repetitively isolated phage inserts (only clones with a frequency of ≥2 are shown). The HA1 receptor-binding domain (RBD) is depicted in yellow. The numbers of phage clones displaying unique sequences encompassing the entire RBD are shown to the right of the alignment. Abbreviations: HA, hemagglutinin; IIV, inactivated influenza vaccine; MN, microneutralization titer.