A commercial ELISA detects high levels of human H5 antibody but cross-reacts with influenza A antibodies.
OBJECTIVE
Commercial serological assays to determine influenza A H5N1 infection are available, although the accuracy and reproducibility of these are not reported in detail. This study aimed to assess the validity of a commercial ELISA H5 hemagglutinin (HA) antibody kit.


METHODS
A commercial ELISA for detection of antibodies towards influenza A H5 HA was evaluated using human sera from vaccinated individuals. The ELISA was used to screen 304 sera with elevated influenza A complement fixation titres collected between the period 1995-2007.


CONCLUSIONS
The ELISA was found to be accurate for sera with high levels of anti-H5 antibodies, and would be useful in clinical settings where a rapid result is required. Thirteen of the stored sera were positive using the ELISA, but were confirmed as negative for H5N1 exposure using further serological tests. Absorption studies suggested that antibodies towards seasonal H3N2 and H1N1 influenza may cross-react with H5 antigen, giving false positive results with the ELISA.
Stelzer-Braid
Sacha
S
Virology Research, Department of Microbiology, South Eastern Area Laboratory Service, Prince of Wales Hospital, Randwick, NSW 2031, Australia.
Wong
Bruce
B
Robertson
Peter
P
Lynch
Garry W
GW
Laurie
Karen
K
Shaw
Robert
R
Barr
Ian
I
Selleck
Paul W
PW
Baleriola
Cristina
C
Escott
Ros
R
Katsoulotos
Gregory
G
Rawlinson
William D
WD
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology*; D003168:Complement Fixation Tests; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000276:immunology*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology; D007251:Influenza, Human / Q000175:diagnosis / Q000276:immunology / Q000821:virology; D008875:Middle Aged; D011933:Reagent Kits, Diagnostic; D055815:Young Adult
D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D011933:Reagent Kits, Diagnostic; C109963:hemagglutinin, avian influenza A virus