Two residues in the hemagglutinin of A/Fujian/411/02-like influenza viruses are responsible for antigenic drift from A/Panama/2007/99.
The H3N2 vaccine strain (A/Panama/2007/99) for the 2003-2004 influenza season did not antigenically match the circulating A/Fujian/411/02-like H3N2 viruses and had reduced effectiveness against influenza outbreaks. A/Wyoming/03/2003, an A/Fujian-like virus, was recommended as the vaccine strain for the 2004-2005 season. A/Wyoming differed from A/Panama by 16 amino acids in the HA1 molecule. Reverse genetics was used to determine the minimal amino acid changes that were responsible for the antigenic drift from A/Panama to A/Wyoming. After substitutions of 2 of the 16 amino acids in the HA (H155T, Q156H), the A/Panama HA variant was antigenically equivalent to A/Wyoming as determined by hemagglutination inhibition and microneutralization assays using ferret postinfection antisera. Conversely, A/Wyoming containing the His-155 and Gln-156 residues from A/Panama was antigenically equivalent to A/Panama. These results indicated that only these two HA residues specified the antigenic drift from A/Panama to A/Wyoming; other amino acid differences between these two H3N2 viruses had minimal impact on virus antigenicity but impacted virus replication efficiency in eggs.
Jin
Hong
H
MedImmune Vaccines, Inc., 297 North Bernardo Avenue, Mountain View, CA 94043, USA. jinh@medimmune.com
Zhou
Helen
H
Liu
Hui
H
Chan
Winnie
W
Adhikary
Lopa
L
Mahmood
Kutubuddin
K
Lee
Min-Shi
MS
Kemble
George
G
D019943:Amino Acid Substitution; D000940:Antigenic Variation / Q000235:genetics; D005814:Genes, Viral; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D009980:Influenza A virus / Q000235:genetics / Q000276:immunology*; D008958:Models, Molecular; D009500:Neutralization Tests; D011487:Protein Conformation
D019267:Hemagglutinin Glycoproteins, Influenza Virus