Figure 6.

Antibody-dependent cellular cytotoxicity in macaque plasma. (A, B) Serially diluted plasma samples were tested for ADCC activity in a SHIV_SF162P3 infected cell assay as described (15). ADCC responses were measured as the dose-dependent loss of luciferase activity in relative light units (RLU) after incubation in comparison to control wells containing NK cells and either infected (maximal) or uninfected (background) CEM.NKR-CCR5-sLTR-Luc cells in the absence of antibody. The dotted line indicates half-maximal lysis of infected cells. (C) 50% ADCC titers were calculated by linear regression. (D) %RLU values were used to determine area under the curve (AUC) values. Differences between log₁₀-transformed %RLU values and 100% RLU, indicating no activity, were calculated at each plasma dilution tested. The sum of these differences for each sample was multiplied by the dilution factor.