CR3 and CR4 ligation interferes with DC maturation. (A) Schematic representation of ApoS consisting of biotinylated human erythrocytes conjugated via streptavidin to biotinylated antibody targeting a chosen apoptotic cell receptor. (B) DCs were incubated with CD11b-, CD11c-, CD32-, or Ig-ApoS for 2 hours, after which noninternalized ApoS were lysed and MCM-mimic (left) or LPS (right) was added to the cultures. After 40 hours, DCs were analyzed for expression of MHC I, MHC II, CD80, CD86, CD40, and CD83 molecules. Mean fluorescence intensity and increase over immature DCs (gray histograms) is shown for each sample. Culture supernatants of DCs stimulated with LPS with or without IFNγ (1000 IU/mL) for 40 hours were tested in an ELISA assay for the indicated cytokines (C, D) and chemokines (F). Representative experiments of at least 3 are shown (B-D, F). In panel E, the average percent of inhibition of cytokine production by CR3-ligated compared with control DCs (Ig) was calculated (number of averaged experiments is shown above each bar; SD is represented with the error bar). In these experiments the DCs were stimulated with LPS and IFNγ (for detection of IL12) or LPS (the rest of the cytokines).