Figure 5. Binding and ADCC activities of mAb F240 against target cells spinoculated with intact HIV virions.

(A,B) Binding of mAb F240, A32, C11, b12 and Synagis to intact AT-2–inactivated HIV-1 BaL virion as determined by FCS, shown as autocorrelation binding curves and percentage of binding. EGFP-CEM-NKr-CCR5-SNAP cells sensitized with AT-2–inactivated HIV-1 BaL were (C) stained for antibody binding and (D) ADCC using the modified rapid fluorometric antibody-mediated cytotoxicity assay (RFADCC)³⁵. Cluster A CD4i antibodies A32, N5-i5, C11 and Synagis were used as controls. The plot represents a mean of two independent experiments normalized to the average A32 values with error bars showing the range between experiments. Lower than reported in ref. 35 the level of binding of N5-i5 results from its low reactivity with secondary antibody. The curves shown are normalized for plateau cytotoxicity values using the most potent anti-Cluster A mAb C11. An AUC (Area Under Curve) for antibodies tested are (cytotoxicity/μg/ml): 519.2 (F240), 235.6 (A32), 374.8 (N5-i5), 674.5 (C11) and 18.2 (Synagis).