title: A rapid method for immunotitration of influenza viruses using flow cytometry.
abstract: Reliable assays for accurate titration of influenza virus in infectious samples are pivotal to both influenza research and vaccine development. A titration assay adopted commonly for this purpose is the plaque assay on Madin-Darby canine kidney (MDCK) cells, despite it being time and labour consuming. A novel assay is described for titration of influenza viruses based on the detection of intracellular viral nucleoprotein (NP) by fluorescence-activated cell sorting (FACS). By using a panel of viruses of different type, subtype and origin, it is demonstrated that there is a mathematical correlation between titres measured by immunotitration and by classical plaque assay on MDCK cells. Moreover, the availability of NP antibodies specific for type A or type B influenza virus ensures the specificity of the assay. Based on speed, accuracy and specificity, it is concluded that the FACS-based immunotitration of influenza virus represents a valid and efficient alternative to the classical plaque assay.
authors.affiliation: Vaccine R&D Division, Crucell Holland BV, P.O. Box 2048, 2301 CA, Leiden, Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Lonsdale
authors.forename: M G
authors.initials: MG
authors.lastname: Pau
authors.forename: M
authors.initials: M
authors.lastname: Oerlemans
authors.forename: C
authors.initials: C
authors.lastname: Ophorst
authors.forename: A
authors.initials: A
authors.lastname: Vooys
authors.forename: M
authors.initials: M
authors.lastname: Havenga
authors.forename: J
authors.initials: J
authors.lastname: Goudsmit
authors.forename: F
authors.initials: F
authors.lastname: UytdeHaag
authors.forename: G
authors.initials: G
authors.lastname: Marzio
mesh_terms: D000818:Animals; D002460:Cell Line; D004285:Dogs; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification* / Q000378:metabolism; D009981:Influenza B virus / Q000302:isolation & purification* / Q000378:metabolism; D019590:Nucleocapsid Proteins; D009698:Nucleoproteins / Q000378:metabolism*; D013997:Time Factors; D014758:Viral Core Proteins / Q000378:metabolism*; D010948:Viral Plaque Assay
chemical_list: D019590:Nucleocapsid Proteins; D009698:Nucleoproteins; D014758:Viral Core Proteins