title: Development and validation of an egg-based potency assay for a trivalent live attenuated influenza vaccine.
abstract: Live attenuated influenza vaccines (LAIVs) targeting seasonal influenza are produced in embryonated eggs and formulated as a trivalent preparation of three live attenuated vaccine strains, one A(H1N1) strain, one A(H3N2) strain and one type B strain. In this study, we describe an egg-based potency assay for estimating the 50% Egg infectious dose (EID50) of individual strains in the trivalent preparation by selective neutralisation of two strains and then estimating the infective titres of the non-neutralised strain. The test is highly specific, and no cross interference of heterologous antisera is observed in the estimation of individual titres. Individual strains with titres in the range of 6.5-7.0 log EID50 per 0.5 ml show intra-assay and inter-assay coefficients of variance ranging from 1.25% to 2.95%. This assay was developed to establish a simple, reliable and inexpensive egg-based assay for estimating the potency of individual strains in a trivalent preparation.
authors.affiliation: Serum Institute of India Limited, 212/2 Off Soli Poonawalla Road, Hadapsar, Pune, Maharashtra 411028, India.
authors.forename: Leena R
authors.initials: LR
authors.lastname: Yeolekar
authors.forename: Rajeev M
authors.initials: RM
authors.lastname: Dhere
mesh_terms: D000818:Animals; D000910:Antibodies, Heterophile; D000914:Antibodies, Viral; D002642:Chick Embryo; D007118:Immunoassay / Q000379:methods* / Q000706:statistics & numerical data; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology; D009981:Influenza B virus / Q000276:immunology; D007252:Influenza Vaccines / Q000032:analysis* / Q000276:immunology; D009500:Neutralization Tests / Q000379:methods / Q000706:statistics & numerical data; D012756:Sheep; D014613:Vaccines, Attenuated / Q000032:analysis / Q000276:immunology
chemical_list: D000910:Antibodies, Heterophile; D000914:Antibodies, Viral; D007252:Influenza Vaccines; D014613:Vaccines, Attenuated