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[摘要]：Background. The H1N1 2009 influenza (H1N1pdm09) pandemic had unexpected features, including lower morbidity and mortality in elderly populations. Methods. We performed in-depth elucidation of antibody responses generated post-H1N1pdm09 vaccination in elderly (aged 66-83 years) and younger (aged 18-45 or 46-65 years) adults using H1N1pdm09 whole-genome-fragment phage display library and measured antibody isotype and affinity to antigenic domains within hemagglutinin (HA). Results. H1N1pdm09 vaccination induced 10-fold higher antibody levels in elderly compared with younger adults. These antibodies primarily targeted the HA1 globular domain, including neutralizing epitopes in the receptor-binding domain. Antibody epitope repertoire, isotype, and affinity maturation after H1N1pdm09 vaccination evolved independently for HA2, HA1, and HA1 N-terminus antigenic regions. Postvaccination serum samples from elderly subjects demonstrated substantially higher avidity than from younger subjects (> 60% vs < 30% resistance to 7 mol/L urea) and slower antibody dissociation rates using surface plasmon resonance. We also identified a gender difference in postvaccination antibody avidity (female < male subjects) in adults < 65 years old. Conclusions. This is the first study in humans that provides evidence for a qualitatively superior antibody response in elderly adults after H1N1pdm09 vaccination. These findings may help explain the age-related mortality observed during the H1N1pdm09 pandemic. The difference in gender specific avidity merits further exploration. |
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