Neutralizing antibodies derived from the B cells of 1918 influenza pandemic survivors.

This residue is located at the antigenic region Sa. It was involved in the binding of a mAb from a 1918 Influenza pandemic survivor by analysis of escape mutants of the related virus Sw/30 after incubation with the mAb. An epitope-specific mAb was tested for neutralization of a series of representative twentieth century H1N1 virus infectivity of MDCK cells. It did not neutralize A/Weiss/43, A/FM/1/47, A/USSR/92/77 and A/New Caledonia/20/99. The epitope residue is conserved in all these strains, except for A/Weiss/43 (Asn substitution).