Thermodynamic parameters of PGT121, PGT128, 2G12 and PG9 binding to BG505 SOSIP.664 gp140 trimers measured by isothermal titration calorimetry.

aThe reported values are averages from at least two independent measurements. The associated errors are approximately 10% of the average. Representative isotherms are shown in Fig. 8.bThe change in Gibbs free energy (ΔG) was determined using the relationship: ΔGbinding = RTlnKd[87].cThe stoichiometry of binding (N) is directly affected by errors in protein concentration measurements, sample impurity and heterogeneity of gp140 glycans.dDissociation constant associated with a second (low affinity) binding event.eThe binding isotherms do not allow the stoichiometry and enthalpy associated with the second binding event to be determined accurately.fData previously described elsewhere [27].