Pre-superinfection (pre-SI) plasma or similar time points for non-superinfected controls were used in a rapid fluorometric ADCC assay in order to assess ADCC-mediated killing, as measured by PKH-26+CFSE- killed target cells identified by flow cytometry. Percentage of killed target cells is shown for the three superinfected individuals (first three bars, filled: ZM282M, ZM247F and ZM211F) and ten non-superinfected controls (open bars). For ZM247F, in which superinfection was detected at 3-months post-seroconversion, we tested this 3-month plasma. Uninfected normal human plasma was used as a negative control for the assay. Error bars represent the SEM between two independent experiments.