Figure 2. Specificity of single domain antibodies to different influenza antigen reference reagents.
ELISA showing binding of 18 purified single domain VHH antibodies to influenza reference reagents prepared from different viral subtypes (A) ELISA comparing binding of purified VHH antibodies at 30 µg/ml against A/California/07/2009 (H1N1pdm09), A/Brisbane/59/2007 (seasonal H1N1),A/Anhui/01/2005 (H5N1) (B) A/Vietnam/1194/2004 (H5N1) (C) A/Indonesia/05/2005 (H5N1) (D) A/HongKong/05/2005 (H5N1) (E) A/Singapore/1/57 (H2N2) (F) A/Hong Kong/1073/99 (H9N2). Antibodies R2b-E8, R2b-D9, R1a-A5, R1a-B6 and R2a-G8 were also positive on A/turkey/Turkey/01/2005 (H5N1), A/Duck/Sing-Q/119-3/97 (H5N3), A/mallard/Eng/727/2006 (H2N3) (data not shown). In addition all antibodies were negative on B virus control (B/Brisbane/60/2008) and on the group 2 strain A/Brisbane/10/07 (H3N2) (data not shown). Control represents a non-binding purified VHH antibody. Binding was measured in duplicate and the average OD 450 nM was plotted against a serial dilution of antibody from 30 µg/ml to 0.001 µg/ml (B-F).