Reproducibility of Serologic Assays for Influenza Virus A (H5N1)

• DOI: 10.3201/eid1508.081754
• Publication Date: 2009-08-19T16:50:45Z
• Authors: Iain Stephenson; Alan Heath; Diane Major; Robert W. Newman; Katja Hoschler; Wang Junzi; Jacqueline M. Katz; Jerry P. Weir; Maria C. Zambon; John M. Wood
• Keywords: Hemagglutination assay; Antibody titer

Abstract Hemagglutination-inhibition (HI) and neutralization are used to evaluate vaccines against influenza virus A (H5N1); however, poor standardization leads interlaboratory variation of results. candidate antibody standard (07/150) was prepared from pooled plasma persons given clade 1 A/Vietnam/1194/2004 vaccine. To test human sheep antiserum, 15 laboratories HI reassortant A/Vietnam/1194/2004, A/turkey/Turkey/1/2005 (clade 2.2), A/Anhui/1/2005 2.3.4) viruses. Interlaboratory observed for both assays, but when titers were expressed relative 07/150, overall percentage geometric coefficient reduced 125% 61% 183% 81% neutralization. Lack variability 2 antigens suggested the need clade-specific standards. Sheep antiserum as a did not reliably reduce variability. The World Health Organization has established 07/150 an international subtype H5 assigned potency 1,000 IU/ampoule.