Figure 4: Measurement of IgG 35PA83 affinity for PA. The affinity of the full-sized IgG 35PA83, deriving from the Fab 35PA83, was measured by surface plasmon resonance using a Biacore X instrument (Biacore, Uppsala, Sweden). A CM5 sensor chip (Biacore) was utilized and around 1000 RU of IgG 35PA83 were immobilized. Sensorgrams were obtained after injections of 41.7 to 1.3 nM of PA83, and analysed using the BIAevaluation software (Biacore). Association (ka) and dissociation constants (kd) were measured as ka = 5.86 x 105 M^-1s^-1 and kd = 1.36 x 10^-5 s^-1 resulting in a KD = 2.32 x 10^-11 M. Experiments using a long dissociation allowed to obtain the equivalent KD value of 2.6 x 10^-11 M.