Reovirus–NAb complexes can be transferred by CD11b+ cells for productive tumor cell infection. (a,b) Target cells (as indicated) were infected with reovirus at MOI 1 in the (a) absence or (b) presence (100 µl immune serum) of reovirus NAb (in the same experiment). After 72 hours, reovirus titer was determined by plaque assay from the cells and supernatant. Representative of three separate experiments. (c,d) Carrier cells were loaded with reovirus at MOI 1 for 2 hours at 4 °C, washed twice in PBS, and cocultured with B16 tumor targets in (c) the absence or (d) presence of reovirus NAb (in the same experiment). After 72 hours, reovirus titer was determined by plaque assay from the cells and supernatant. Representative of two separate experiments. (e) Carrier cells were loaded with reovirus–NAb complexes at MOI 1 and cocultured with B16 targets. After 72 hours, reovirus titer was determined by plaque assay from the cells and supernatant. Representative of three separate experiments.