GM-CSF conditioning enhances FcγR1 receptor expression and NAb–reovirus immune complex transfer from CD11b+ cells. (a) Intact LN/splenocyte cultures (each lane representing cultures from an individual mouse, three per treatment), or cultures depleted of specific cell populations as indicated, were cultured ± GM-CSF 10 ng/ml), and FcγR1 expression was determined by qRTPCR. Representative of four separate experiments. (b) Microbead-purified CD11b+ cells were treated ± GM-CSF and FcγR1 expression was determined as in a. Representative of two separate experiments. (c) Purified CD11b+ cells, ± GM-CSF, were treated as indicated, washed in PBS, and cocultured with B16 cells. After 72 hours, reovirus titer was determined by plaque assay from the cells and supernatant. (d) B16 tumor cells, or magnetic bead-purified CD11b+ cells, were infected with reovirus at an MOI 1 ± reovirus NAb. After 2 hours, cells were washed three times in PBS, cultured, and reovirus titers were determined by plaque assay from the cells and supernatant at the time points indicated. Graph shows mean ± SD and is representative of two separate experiments.