Fig. 2.

Phagocytosis of large particle loads is not Syt VII dependent in immature DCs. (A) Texas Red zymosan was added to DCs at 25 or 50 particles/cell, for 0.5, 1, 2, or 2.5 h, and the number of internalized particles was determined microscopically after washing, fixation and staining with anti-zymosan to detect extracellular particles. The data represents the mean +/− SD of internalized particles per 100 DCs. Over 300 cells per coverslip were counted in triplicate. (B) DCs from Syt VII^+/+ or Syt VII^−/− mice were stained live on ice for surface MHC-II, after incubation with (green) or without (blue) unlabeled zymosan at 50 particles/cell for 1 h at 37 °C. An isotype control antibody is shown in red. (C) Zymosan induces maturation in part of the DC population after 18 h. DCs from Syt VII^+/+ mice were incubated with unlabeled zymosan at 50 particles/cell (green) or LPS (50 ng/ml) (blue) for 18 h, harvested and stained live with antibodies to MHC-II and CD86. Surface levels of MHC-II and CD86 from unstimulated (no zymosan or LPS) DCs cultured in parallel for 18 h are shown for comparison (red). The results shown are representative of several independent experiments.