Reproducibility of serology assays for pandemic influenza H1N1: Collaborative study to evaluate a candidate WHO International Standard

• Published in: Vaccine Vol. 30; no. 2; pp. 210 - 217
• Main Authors: Wood, John M., Major, Diane, Heath, Alan, Newman, Robert W., Höschler, Katja, Stephenson, Iain, Clark, Tristan, Katz, Jacqueline M., Zambon, Maria C.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 05.01.2012; Elsevier Limited
• Subjects: Agreements; Allergy and Immunology; Antibodies, Viral - blood; Antibody standard; Avian flu; bioassays; Cell culture; Clinical trials; Eggs; Ethics; Haemagglutination–inhibition; Human subjects; Humans; immune response; Influenza; Influenza A Virus, H1N1 Subtype - immunology; Influenza Vaccines - immunology; Influenza Vaccines - standards; International Cooperation; International standards; Laboratories; Neutralisation; neutralization tests; Pandemic; Pandemics; Reference Standards; Reproducibility of Results; Serologic Tests - methods; Serologic Tests - standards; Serology; Swine flu; Vaccines; Viruses; World Health Organization; Antibody standard; Haemagglutination–inhibition; Pandemic; Serology; Neutralisation; Influenza
• ISSN: 0264-410X; 1873-2518; 1873-2518
• DOI: 10.1016/j.vaccine.2011.11.019

► We evaluated the reproducibility of pandemic H1N1 influenza antibody assays. ► A candidate pandemic H1N1 antibody standard was assessed. ► Inter-laboratory variability was high but was reduced by use of the standard. ► The International Standard for pandemic H1N1 antibody has been established by WHO. ► There was no overall correlation between HI and VN titres. Haemagglutination–inhibition (HI) and virus neutralisation (VN) assays are used to evaluate immunogenicity of pandemic H1N1 vaccines; however these bioassays are poorly standardised leading to inter-laboratory variation. A candidate International Standard (IS) for antibody to H1N1pdm virus (09/194) was prepared from pooled sera of subjects who had either recovered from H1N1pdm infection or who had been immunised with an adjuvanted subunit vaccine prepared from reassortant virus NYMC X-179A (derived from A/California/7/2009 virus). Ten laboratories from seven countries tested the candidate IS, 09/194 and a panel of human sera by HI and VN using the A/California/7/2009 virus (six laboratories) and/or the reassortant virus NYMC X-179A (ten laboratories). As expected, the inter-laboratory variability for HI and VN assay results was high. For results of antibody tests to NYMC X-179A, the % geometric coefficient of variation (%GCV) for 09/194 between laboratories was 83% for HI and 192% for VN. For tests of all sera, the median %GCV ranged from 95 to 345% for HI (80-fold variation) and 204 to 383% for VN (109-fold variation), but for the titres relative to 09/194 the median %GCV was much reduced (HI 34–231%; VN 44–214%). For tests of antibody to the A/California/7/2009 wild type virus there were similar reductions in %GCV when 09/194 was used. These results suggest that 09/194 will be of use to standardise assays of antibody to A/California/7/2009 vaccine and 09/194 has now been established by WHO as an IS for antibody to A/California/7/2009 with an assigned potency of 1300 IU per ml.