title: Equivalence of ELISpot assays demonstrated between major HIV network laboratories.
abstract: BACKGROUND
  The Comprehensive T Cell Vaccine Immune Monitoring Consortium (CTC-VIMC) was created to provide standardized immunogenicity monitoring services for HIV vaccine trials. The ex vivo interferon-gamma (IFN-γ) ELISpot is used extensively as a primary immunogenicity assay to assess T cell-based vaccine candidates in trials for infectious diseases and cancer. Two independent, GCLP-accredited central laboratories of CTC-VIMC routinely use their own standard operating procedures (SOPs) for ELISpot within two major networks of HIV vaccine trials. Studies are imperatively needed to assess the comparability of ELISpot measurements across laboratories to benefit optimal advancement of vaccine candidates.
  
  
  METHODS
  We describe an equivalence study of the two independently qualified IFN-g ELISpot SOPs. The study design, data collection and subsequent analysis were managed by independent statisticians to avoid subjectivity. The equivalence of both response rates and positivity calls to a given stimulus was assessed based on pre-specified acceptance criteria derived from a separate pilot study.
  
  
  RESULTS
  Detection of positive responses was found to be equivalent between both laboratories. The 95% C.I. on the difference in response rates, for CMV (-1.5%, 1.5%) and CEF (-0.4%, 7.8%) responses, were both contained in the pre-specified equivalence margin of interval [-15%, 15%]. The lower bound of the 95% C.I. on the proportion of concordant positivity calls for CMV (97.2%) and CEF (89.5%) were both greater than the pre-specified margin of 70%. A third CTC-VIMC central laboratory already using one of the two SOPs also showed comparability when tested in a smaller sub-study.
  
  
  CONCLUSIONS
  The described study procedure provides a prototypical example for the comparison of bioanalytical methods in HIV vaccine and other disease fields. This study also provides valuable and unprecedented information for future vaccine candidate evaluations on the comparison and pooling of ELISpot results generated by the CTC-VIMC central core laboratories.
authors.affiliation: International AIDS Vaccine Initiative Human Immunology Laboratory, Imperial College, London, United Kingdom. d.gill@imperial.ac.uk
authors.forename: Dilbinder K
authors.initials: DK
authors.lastname: Gill
authors.forename: Yunda
authors.initials: Y
authors.lastname: Huang
authors.forename: Gail L
authors.initials: GL
authors.lastname: Levine
authors.forename: Anna
authors.initials: A
authors.lastname: Sambor
authors.forename: Donald K
authors.initials: DK
authors.lastname: Carter
authors.forename: Alicia
authors.initials: A
authors.lastname: Sato
authors.forename: Jakub
authors.initials: J
authors.lastname: Kopycinski
authors.forename: Peter
authors.initials: P
authors.lastname: Hayes
authors.forename: Bridget
authors.initials: B
authors.lastname: Hahn
authors.forename: Josephine
authors.initials: J
authors.lastname: Birungi
authors.forename: Tony
authors.initials: T
authors.lastname: Tarragona-Fiol
authors.forename: Hong
authors.initials: H
authors.lastname: Wan
authors.forename: Mark
authors.initials: M
authors.lastname: Randles
authors.forename: Andrew Raxworthy
authors.initials: AR
authors.lastname: Cooper
authors.forename: Aloysius
authors.initials: A
authors.lastname: Ssemaganda
authors.forename: Lorna
authors.initials: L
authors.lastname: Clark
authors.forename: Pontiano
authors.initials: P
authors.lastname: Kaleebu
authors.forename: Steven G
authors.initials: SG
authors.lastname: Self
authors.forename: Richard
authors.initials: R
authors.lastname: Koup
authors.forename: Blake
authors.initials: B
authors.lastname: Wood
authors.forename: M Juliana
authors.initials: MJ
authors.lastname: McElrath
authors.forename: Josephine H
authors.initials: JH
authors.lastname: Cox
authors.forename: John
authors.initials: J
authors.lastname: Hural
authors.forename: Jill
authors.initials: J
authors.lastname: Gilmour
mesh_terms: D015492:AIDS Serodiagnosis / Q000379:methods / Q000592:standards*; D016915:AIDS Vaccines / Q000627:therapeutic use*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D015658:HIV Infections / Q000517:prevention & control*; D018023:HIV Seronegativity; D015497:HIV-1 / Q000378:metabolism; D006801:Humans; D007107:Immune System; D007371:Interferon-gamma / Q000378:metabolism; D007753:Laboratories / Q000592:standards; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D015233:Models, Statistical; D010865:Pilot Projects; D015203:Reproducibility of Results; D013601:T-Lymphocytes / Q000378:metabolism*
chemical_list: D016915:AIDS Vaccines; D007371:Interferon-gamma