title: Evaluation of in vitro cross-reactivity to avian H5N1 and pandemic H1N1 2009 influenza following prime boost regimens of seasonal influenza vaccination in healthy human subjects: a randomised trial.
abstract: BACKGROUND
  Recent studies have demonstrated that inactivated seasonal influenza vaccines (IIV) may elicit production of heterosubtypic antibodies, which can neutralize avian H5N1 virus in a small proportion of subjects. We hypothesized that prime boost regimens of live and inactivated trivalent seasonal influenza vaccines (LAIV and IIV) would enhance production of heterosubtypic immunity and provide evidence of cross-protection against other influenza viruses.
  
  
  METHODS
  In an open-label study, 26 adult volunteers were randomized to receive one of four vaccine regimens containing two doses of 2009-10 seasonal influenza vaccines administered 8 (±1) weeks apart: 2 doses of LAIV; 2 doses of IIV; LAIV then IIV; IIV then LAIV. Humoral immunity assays for avian H5N1, 2009 pandemic H1N1 (pH1N1), and seasonal vaccine strains were performed on blood collected pre-vaccine and 2 and 4 weeks later. The percentage of cytokine-producing T-cells was compared with baseline 14 days after each dose.
  
  
  RESULTS
  Subjects receiving IIV had prompt serological responses to vaccine strains. Two subjects receiving heterologous prime boost regimens had enhanced haemagglutination inhibition (HI) and neutralization (NT) titres against pH1N1, and one subject against avian H5N1; all three had pre-existing cross-reactive antibodies detected at baseline. Significantly elevated titres to H5N1 and pH1N1 by neuraminidase inhibition (NI) assay were observed following LAIV-IIV administration. Both vaccines elicited cross-reactive CD4+ T-cell responses to nucleoprotein of avian H5N1 and pH1N1. All regimens were safe and well tolerated.
  
  
  CONCLUSIONS
  Neither homologous nor heterologous prime boost immunization enhanced serum HI and NT titres to 2009 pH1N1 or avian H5N1 compared to single dose vaccine. However heterologous prime-boost vaccination did lead to in vitro evidence of cross-reactivity by NI; the significance of this finding is unclear. These data support the strategy of administering single dose trivalent seasonal influenza vaccine at the outset of an influenza pandemic while a specific vaccine is being developed.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01044095.
authors.affiliation: Department of Immunology and Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand. delia.bethell@afrims.org
authors.forename: Delia
authors.initials: D
authors.lastname: Bethell
authors.forename: David
authors.initials: D
authors.lastname: Saunders
authors.forename: Anan
authors.initials: A
authors.lastname: Jongkaewwattana
authors.forename: Jarin
authors.initials: J
authors.lastname: Kramyu
authors.forename: Arunee
authors.initials: A
authors.lastname: Thitithayanont
authors.forename: Suwimon
authors.initials: S
authors.lastname: Wiboon-ut
authors.forename: Kosol
authors.initials: K
authors.lastname: Yongvanitchit
authors.forename: Amporn
authors.initials: A
authors.lastname: Limsalakpetch
authors.forename: Utaiwan
authors.initials: U
authors.lastname: Kum-Arb
authors.forename: Nichapat
authors.initials: N
authors.lastname: Uthaimongkol
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: Garcia
authors.forename: Ans E
authors.initials: AE
authors.lastname: Timmermans
authors.forename: Malik
authors.initials: M
authors.lastname: Peiris
authors.forename: Stephen
authors.initials: S
authors.lastname: Thomas
authors.forename: Anneke
authors.initials: A
authors.lastname: Engering
authors.forename: Richard G
authors.initials: RG
authors.lastname: Jarman
authors.forename: Duangrat
authors.initials: D
authors.lastname: Mongkolsirichaikul
authors.forename: Carl
authors.initials: C
authors.lastname: Mason
authors.forename: Nuanpan
authors.initials: N
authors.lastname: Khemnu
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Tyner
authors.forename: Mark M
authors.initials: MM
authors.lastname: Fukuda
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Walsh
authors.forename: Sathit
authors.initials: S
authors.lastname: Pichyangkul
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D001717:Birds; D003429:Cross Reactions; D005240:Feasibility Studies; D005260:Female; D006262:Health; D006801:Humans; D007117:Immunization, Secondary / Q000009:adverse effects / Q000379:methods*; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology / Q000502:physiology; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology / Q000502:physiology; D005585:Influenza in Birds / Q000276:immunology* / Q000517:prevention & control; D007251:Influenza, Human / Q000453:epidemiology / Q000276:immunology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D009975:Orthomyxoviridae / Q000276:immunology* / Q000502:physiology; D058873:Pandemics / Q000517:prevention & control*; D010865:Pilot Projects; D012449:Safety; D012621:Seasons; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology; D014611:Vaccination / Q000009:adverse effects / Q000379:methods*; D014765:Viral Vaccines / Q000009:adverse effects / Q000276:immunology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines
references.citation: Nat Immunol. 2011 Jul 10;12(8):786-95
references.pmid: 21743478
references.citation: Drugs. 2011 Aug 20;71(12):1591-622
references.pmid: 21861544
references.citation: Stat Med. 1995 Sep 15;14(17):1933-40
references.pmid: 8532986
references.citation: J Immunol Methods. 1990 Dec 31;135(1-2):49-57
references.pmid: 1703190
references.citation: Eur J Immunol. 1980 May;10(5):396-401
references.pmid: 6967815
references.citation: J Clin Virol. 2010 Jan;47(1):29-33
references.pmid: 19897409
references.citation: J Eval Clin Pract. 2004 May;10(2):307-12
references.pmid: 15189396
references.citation: Nat Med. 2003 Jun;9(6):729-35
references.pmid: 12766765
references.citation: Scand J Immunol. 2004 Jan;59(1):1-15
references.pmid: 14723616
references.citation: Lancet. 2006 Sep 16;368(9540):991-7
references.pmid: 16980114
references.citation: Nat Med. 2012 Jan 29;18(2):274-80
references.pmid: 22286307
references.citation: BMJ. 2010 Mar 23;340:c332
references.pmid: 20332509
references.citation: Semin Pediatr Infect Dis. 2006 Oct;17(4):206-12
references.pmid: 17055372
references.citation: JAMA. 2009 Mar 4;301(9):945-53
references.pmid: 19255113
references.citation: J Exp Med. 2011 Jan 17;208(1):181-93
references.pmid: 21220454
references.citation: Scand J Immunol. 1978;7(1):73-80
references.pmid: 305613
references.citation: J Virol. 2000 Nov;74(21):10025-33
references.pmid: 11024131
references.citation: Proc Natl Acad Sci U S A. 2009 Dec 1;106(48):20365-70
references.pmid: 19918065
references.citation: Lancet. 2001 Jun 16;357(9272):1937-43
references.pmid: 11425416
references.citation: N Engl J Med. 1972 Jun 22;286(25):1329-32
references.pmid: 5027388
references.citation: J Infect Dis. 2006 Oct 15;194(8):1032-9
references.pmid: 16991077
references.citation: Emerg Infect Dis. 2008 Jan;14(1):121-8
references.pmid: 18258091
references.citation: J Infect Dis. 2005 Apr 15;191(8):1210-5
references.pmid: 15776364
references.citation: Vaccine. 2009 Jun 2;27(27):3568-75
references.pmid: 19464536
references.citation: J Virol. 2011 Jan;85(1):448-55
references.pmid: 20980523
references.citation: Science. 2010 Aug 27;329(5995):1060-4
references.pmid: 20647428
references.citation: Lancet. 1973 Mar 24;1(7804):623-5
references.pmid: 4121842
references.citation: J Clin Invest. 2008 Oct;118(10):3478-90
references.pmid: 18802496
references.citation: PLoS One. 2010 Jan 20;5(1):e8805
references.pmid: 20098712
references.citation: J Gen Virol. 2007 Sep;88(Pt 9):2473-2478
references.pmid: 17698656
references.citation: Proc Natl Acad Sci U S A. 2010 Jul 13;107(28):12658-63
references.pmid: 20615945
references.citation: Proc Natl Acad Sci U S A. 1985 Mar;82(6):1785-9
references.pmid: 3872457
references.citation: J Virol. 2010 Apr;84(7):3312-9
references.pmid: 20071564
references.citation: Proc Natl Acad Sci U S A. 2012 Feb 14;109(7):2485-90
references.pmid: 22308386