101. Epitope specificity of anti-HA2 antibodies induced in humans during influenza infection.
- Author
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Staneková Z, Mucha V, Sládková T, Blaškovičová H, Kostolanský F, and Varečková E
- Subjects
- Adolescent, Adult, Aged, Child, Female, Humans, Influenza Vaccines administration & dosage, Influenza Vaccines immunology, Male, Middle Aged, Young Adult, Antibodies, Viral blood, Epitopes immunology, Hemagglutinins, Viral immunology, Influenza, Human immunology
- Abstract
Background: The conserved, fusion-active HA2 glycopolypeptide (HA2) subunit of influenza A hemagglutinin comprises four distinct antigenic sites. Monoclonal antibodies (MAbs) recognizing three of these sites are broadly cross-reactive and protective., Objectives: This study aimed to establish whether antibodies specific to these three antigenic sites were elicited during a natural influenza infection or by vaccination of humans., Methods: Forty-five paired acute and convalescent sera from individuals with a confirmed influenza A (subtype H3) infection were examined for the presence of HA2-specific antibodies. The fraction of antibodies specific to three particular antigenic sites (designated IIF4, FC12, and CF2 here) was investigated using competitive enzyme immunoassay., Results: Increased levels of antibodies specific to an ectodomain of HA2 (EHA2: N-terminal residues 23-185 of HA2) were detected in 73% of tested convalescent sera (33/45), while an increased level of antibodies specific to the HA2 fusion peptide (N-terminal residues 1-38) was induced in just 15/45 individuals (33%). Competitive assays confirmed that antibodies specific to the IIF4 epitope (within HA2 residues 125-175) prevailed in 86% (13/15) over those specific to the other two epitopes during infection. However, only a negligible increase in HA2-specific antibodies was detectable following vaccination with a current subunit vaccine., Conclusions: We observed that the antigenic site localized within N-terminal HA2 residues 125-175 was more immunogenic than that within residues 1-38 (HA2 fusion protein), although both are weak natural immunogens. We suggest that new anti-influenza vaccines should include HA2 (or specific epitopes localized within this glycopolypeptide) to enhance their cross-protective efficacy., (© 2012 Blackwell Publishing Ltd.)
- Published
- 2012
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