Infection with L monocytogenes overturns the inhibitory impact of CR3. DCs preexposed to CD11b- or control Ig-ApoS for 2 hours were incubated in the presence of L monocytogenes, MCM-mimic, or media alone for the remaining 40-hour culture. (A) Maturation of DCs (CD80, MHC I) was assessed by flow cytometry. Listeria-infected DCs were compared with those exposed to MCM-mimic. Inhibition was calculated as the percentage decrease in mean fluorescence in CD11b-ApoS–exposed DCs compared with control, Ig-ApoS–exposed DCs. The left panel shows the average of 6 experiments with P values (paired Student t test) and the right panel a representative experiment. (B) DCs preincubated with CD11b- or control Ig-ApoS were infected with Listeria or exposed to MCM-mimic. After 24 hours, DCs were washed and cocultured with naive allogeneic CD4⁺ T cells for 6 days. Proliferation of T cells was assessed by determining dilution of CFSE dye in T-cell membranes, and amount of secreted IFNγ was determined by ELISA assay. The percentages above each column denote the difference in value of control Ig-ApoS over CD11b-ApoS. Results from 2 experiments are shown. Error bars represent SD of duplicate test wells.