Figure 6. HA stalk-specific mAbs bind with lower affinity.
(A-B, D) 35 HA head-reactive mAbs, 33 sc70-1F02 competing and 16 noncompeting HA stalk-specific mAbs were tested by ELISA for binding to Cal09 rHA or whole virus. Each line in (A) and (D) represents the paired apparent kD of binding of each mAb to rHA or whole virus. In (B) each dot represents the apparent kD of one mAb with the median of each group shown by a horizontal line. Data representative of 2-3 independent experiments. Statistical significance was determined using the Wilcoxon test (A and D) or Mann-Whitney test (B). (C) Testing of a subset of HA-stalk versus HA-head reactive antibodies by surface plasmon resonance to determine, association (Ka), dissociation (Kd), and affinities (KD). Shown is mean of two independent experiments. Statistical significance was determined using an unpaired two-tailed t-test.