The study of heterosubtypic neutralising antibody responses against H5N1 influenza viruses in human subjects using a comparative serology approach

Background: The continuous rapid genetic and antigenic evolution of H5 subtype influenza viruses

human vaccines and the ability to undertake effective serosurveillance in susceptible populations.

and 2007 and previously found to be positive for antibodies against H5N1 as determined by serial

combination with haemagglutination-inhibition (HI) assays using a clade 1 and a clade 2 H5N1

A/Vietnam/1194/04 H5 and A/chicken/Italy/13474/99 H7 pseudotypes. IC50 neutralizing antibody

10240. Seven of 68 (10.3%) sera were found to be negative against A/Vietnam/1194/04 pseudotypes.

from < 40 (cut-off) to 1:160-320. Forty-seven of 68 (69.1%) sera were found to be negative against

pseudotype assay can efficiently measure cross-reactive antibody responses that are not detected by

three serologic assays (PPN, SRH, HI) measure antibodies with different (functional) overlapping

specificities, contributing to a comprehensive analysis of humoral immunity to influenza viruses.