Figure 3. Growth inhibition of transgenic Plasmodium knowlesi (Pk) lines expressing PvDBP.

(A) Assays of growth Inhibitory activity (GIA) by the ten anti-PvDBPII human mAbs against five different Pk lines: ‘Wild type’ Pk (A1-H.1); PkDBPα^OR; PkDBPα^OR/Δβγ; PvDBP^OR and PvDBP^OR/Δβγ. Inhibition was tested in a two-fold dilution series starting at 1 mg/mL. Data points represent the mean of three technical replicates, while the error bars represent the standard deviation. The EC₅₀ values (interpolated by non-linear regression) are shown in ascending rank order for the seven mAbs which reached >50 % GIA against PvDBP^OR/Δβγ at the maximum concentration (1 mg/mL). (B) k_on (on-rate), k_off (off-rate) and K_D (dissociation constant), plotted against GIA EC₃₀ for PvDBP^OR/Δβγ. EC₃₀ values were used to include weaker-neutralising mAbs and were interpolated from non-linear regression curves. Kinetic data are as Figure 1 and Supplementary Table 2. Spearman’s rank correlation coefficient (ρ) and P value are shown.