scientists screened 104,000 peripheral-blood plasma cells from eight recently infected or vaccinated donors for antibodies that recognize each of three diverse influenza strains: h1n1 (swine-origin) and h5n1 and h7n7 (highly pathogenic avian influenzas.) from one donor, they isolated four plasma cells that produced an identical antibody, which they called fi6. this antibody binds all 16 ha subtypes, neutralizes infection, and protects mice and ferrets from lethal infection. the most broadly reactive antibodies that had previously been discovered recognized either one group of ha subtypes or the other, highlighting how remarkable fi6 is in its ability to target the gamut of influenza subtypes.