title: Serological responses following influenza A H1N1 2009 infection in adults.
abstract: OBJECTIVE
  The aim of this study was to determine the humoral immune response to influenza A H1N1 2009 and cross reactivity against seasonal H1N1 and H3N2 strains.
  
  
  METHODS
  Baseline and convalescent sera from 88 subjects with confirmed H1N1 2009 were screened for serological responses by HAI assay.
  
  
  RESULTS
  Protective antibody titres to H1N1 2009 were present in 87% post-infection, but varied with age, sex and pregnancy. Some cross reactivity with seasonal influenza strains was observed.
  
  
  CONCLUSIONS
  Females and pregnant subjects had an attenuated immune response to H1N1 2009 in comparison to the rest of the study population. Antibodies from the serum of H1N1 2009 infected subjects cross reacted with seasonal H1N1 and H3N2 influenza viruses.
authors.affiliation: Department of Microbiology and Infectious Diseases, Flinders University, Flinders Medical Centre, Flinders Drive, Bedford Park, South Australia 5042, Australia.
authors.forename: Sophia
authors.initials: S
authors.lastname: Tan
authors.forename: David L
authors.initials: DL
authors.lastname: Gordon
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Honda-Okubo
authors.forename: Nikolai
authors.initials: N
authors.lastname: Petrovsky
authors.forename: Peter
authors.initials: P
authors.lastname: Phillips
authors.forename: Sandra
authors.initials: S
authors.lastname: Huddleston
authors.forename: Tania A
authors.initials: TA
authors.lastname: Sadlon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D003429:Cross Reactions; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology / Q000821:virology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral