Fig. 9.
The impaired capacity of high-affinity MoAb to induce apoptosis is not observed under conditions of ligand multivalency. Cells were cultured for 42 hours with bivalent forms of high-affinity MoAb HB57, intermediate-affinity MoAb Mu53, or isotype control MOPC-21 or with multivalent MoAb:dextran conjugates of MoAb HB57, MoAb Mu53, or MOPC-21 (as HB57:UPC:dextran, Mu53:UPC:dextran, and MOPC-21:UPC:dextran; see Materials and Methods) at a concentration of 10 μg/mL MoAb protein per culture (MoAb:cell ratio = 2 μg/105 cells). Apoptosis was assessed by FITC-annexin V binding as in Fig 1. The results represent the mean percentage of annexin-positive cells in two experiments ± SEM.
