Antibody classification.

1Antibody neutralisation category, R is H1N1 restricted neutralisation activity, C refers to a cross-neutralising antibody, N is non-neutralising antibody2Hemagglutination inhibition (HI) titre was given as the minimum dilution of antibody at which inhibition of agglutination of turkey erythrocytes was observed (in µg/ml of purified antibody). Values are given as an average of three independent assays. Laboratory adapted A(H1N1) strain (X-181) was used.3Single cycle affinity determination on full length HA (D18-I530) and globular head HA1 domain (residues D18-R344) derived from A/California/06/2009 (H1N1pdm09). Affinity is given in nM.4Binding to phage displayed fragments of HA as indicated in ELISA (see Figure 5B).5ELISA on HA of A/California/07/2009 (H1N1pdm09) treated with low pH and neutral pH (see Figure 5A).