TY - JOUR T1 - Identification of human vaccinees that possess antibodies targeting the egg-adapted hemagglutinin receptor binding site of an H1N1 influenza vaccine strain JF - bioRxiv DO - 10.1101/249615 SP - 249615 AU - Tyler A. Garretson AU - Joshua G. Petrie AU - Emily T. Martin AU - Arnold S. Monto AU - Scott E. Hensley Y1 - 2018/01/01 UR - http://biorxiv.org/content/early/2018/01/17/249615.abstract N2 - Human influenza viruses passaged in eggs often acquire mutations in the hemagglutinin (HA) receptor binding site (RBS). To determine if egg-adapted H1N1 vaccines commonly elicit antibodies targeting the egg-adapted RBS of HA, we completed hemagglutinin-inhibition assays with A/California/7/2009 HA and egg-adapted A/California/7/2009-X-179A HA using sera collected from 159 humans vaccinated with seasonal influenza vaccines during the 2015-16 season. We found that ~5% of participants had ≥4-fold higher antibody titers to the egg-adapted viral strain compared to wild type viral strain. We used reverse-genetics to demonstrate that a single egg-adapted HA RBS mutation (Q226R) was responsible for this phenotype. ER -