biostudies-literatureGilchuk IMNCATS NIH HHSNIAID NIH HHSNIH/NCATSNIH/NIAIDe152403https://www.ebi.ac.uk/biostudies/studies/S-EPMC8525637biostudies-literatureUnknown6(19)Avian H7N9 influenza viruses cause sporadic outbreaks of human infections and threaten to cause a major pandemic. The breadth of B cell responses to natural infection and the dominant antigenic sites recognized during first exposure to H7 HA following infection are incompletely understood. Here, we studied the B cell response to H7 HA of 2 individuals who had recovered from natural H7N9 virus infection. We used competition binding, hydrogen-deuterium mass spectrometry, and single-particle negative stain electron microscopy to identify the patterns of molecular recognition of the antibody responses to H7 HA. We found that circulating H7-reactive B cells recognized a diverse antigenic landscape on the HA molecule, including HA head domain epitopes in antigenic sites A and B and in the trimerJCI insightHuman antibody recognition of H7N9 influenza virus HA following natural infection.PMC8525637UL1 TR002243HHSN272201400024CU01 AI150739Trivette ALi STurner HLBombardi RGCrowe JEKose NBangaru SWard ABGilchuk IMCarnahan RHfalseHuman antibody recognition of H7N9 influenza virus HA following natural infection.Avian H7N9 influenza viruses cause sporadic outbreaks of human infections and threaten to cause a major pandemic. The breadth of B cell responses to natural infection and the dominant antigenic sites recognized during first exposure to H7 HA following infection are incompletely understood. Here, we studied the B cell response to H7 HA of 2 individuals who had recovered from natural H7N9 virus infection. We used competition binding, hydrogen-deuterium mass spectrometry, and single-particle negative stain electron microscopy to identify the patterns of molecular recognition of the antibody responses to H7 HA. We found that circulating H7-reactive B cells recognized a diverse antigenic landscape on the HA molecule, including HA head domain epitopes in antigenic sites A and B and in the trimer2021-01-01T00:00:00Z2021 Oct2026-05-08T15:49:59.045Z2025-02-19T00:03:07.305ZS-EPMC85256373443730110.1172/jci.insight.152403