Fig 2. Trypanolytic activity of recombinant APOL1.

The percentage of viable trypanosomes was determined following a 24-hour exposure to media containing serial dilutions of A) recombinant Human APOL1 protein and B) recombinant P. papio APOL1 protein. Representative T. brucei sub-species strains were tested: T. b. brucei (strain STIB247), T. b. rhodesiense (strain EATRO98), T. b. gambiense group 1 (strain ELIANE), and T. b. gambiense group 2 (strain STIB386). Additional assays were performed with different strains of T. b. gambiense group 1 and are provided in S4 Fig. The mean percentage cell survival ± SD, relative to protein-free control, was calculated from at least three independent experiments. Dose–response curves and IC₅₀ values with 95% confidence intervals (CI) were determined using GraphPad Prism software version 7. APOL1-mediated lysis of each isolate was prevented by the inclusion of an acidotropic agent (10 mM NH₄Cl) in the assay.