title: Multilaboratory comparison of Streptococcus pneumoniae opsonophagocytic killing assays and their level of agreement for the determination of functional antibody activity in human reference sera.
abstract: Antibody-mediated killing of Streptococcus pneumoniae (pneumococcus) by phagocytes is an important mechanism of protection of the human host against pneumococcal infections. Measurement of opsonophagocytic antibodies by use of a standardized opsonophagocytic assay (OPA) is important for the evaluation of candidate vaccines and required for the licensure of new pneumococcal conjugate vaccine formulations. We assessed agreement among six laboratories that used their own optimized OPAs on a panel of 16 human reference sera for 13 pneumococcal serotypes. Consensus titers, estimated using an analysis-of-variance (ANOVA) mixed-effects model, provided a common reference for assessing agreement among these laboratories. Agreement was evaluated in terms of assay accuracy, reproducibility, repeatability, precision, and bias. We also reviewed four acceptance criterion intervals for assessing the comparability of protocols when assaying the same reference sera. The precision, accuracy, and concordance results among laboratories and the consensus titers revealed acceptable agreement. The results of this study indicate that the bioassays evaluated in this study are robust, and the resultant OPA values are reproducible for the determination of functional antibody titers specific to 13 pneumococcal serotypes when performed by laboratories using highly standardized but not identical assays. The statistical methodologies employed in this study may serve as a template for evaluating future multilaboratory studies.
authors.affiliation: Biostatistics Office, DBD, Centers for Disease Control and Prevention, Building 1, Room 5044, MS C-09, 1600 Clifton Road, Atlanta, GA 30333, USA. CRose@cdc.gov
authors.forename: Charles E
authors.initials: CE
authors.lastname: Rose
authors.forename: Sandra
authors.initials: S
authors.lastname: Romero-Steiner
authors.forename: Robert L
authors.initials: RL
authors.lastname: Burton
authors.forename: George M
authors.initials: GM
authors.lastname: Carlone
authors.forename: David
authors.initials: D
authors.lastname: Goldblatt
authors.forename: Moon H
authors.initials: MH
authors.lastname: Nahm
authors.forename: Lindsey
authors.initials: L
authors.lastname: Ashton
authors.forename: Mitch
authors.initials: M
authors.lastname: Haston
authors.forename: Nina
authors.initials: N
authors.lastname: Ekström
authors.forename: Raili
authors.initials: R
authors.lastname: Haikala
authors.forename: Helena
authors.initials: H
authors.lastname: Käyhty
authors.forename: Isabelle
authors.initials: I
authors.lastname: Henckaerts
authors.forename: Nathalie
authors.initials: N
authors.lastname: Durant
authors.forename: Jan T
authors.initials: JT
authors.lastname: Poolman
authors.forename: Phil
authors.initials: P
authors.lastname: Fernsten
authors.forename: Xinhong
authors.initials: X
authors.lastname: Yu
authors.forename: Branda T
authors.initials: BT
authors.lastname: Hu
authors.forename: Kathrin U
authors.initials: KU
authors.lastname: Jansen
authors.forename: Milan
authors.initials: M
authors.lastname: Blake
authors.forename: Elles R
authors.initials: ER
authors.lastname: Simonetti
authors.forename: Peter W M
authors.initials: PW
authors.lastname: Hermans
authors.forename: Brian D
authors.initials: BD
authors.lastname: Plikaytis
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D019411:Clinical Laboratory Techniques / Q000379:methods / Q000592:standards*; D006801:Humans; D007118:Immunoassay / Q000379:methods / Q000592:standards; D009895:Opsonin Proteins / Q000276:immunology*; D010586:Phagocytes / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology*; D011008:Pneumococcal Infections / Q000175:diagnosis* / Q000276:immunology; D012015:Reference Standards; D015203:Reproducibility of Results; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D009895:Opsonin Proteins