Effect of CD2 engagement on DC cytokine production and endocytic activity. (A-B) Freshly isolated pDCs (A) and GM-CSF– and IL-4–differentiated MDDCs (B) were cultured in the presence (▴ [IL-12] and ▪ [IL-1β]) or absence (♦ [IL-12] and * [IL-1β]) of anti-CD2 (T-11₁ and T-11₂) mAbs for 24 hours. The supernatants were assayed for IL-1β and IL-12 by ELISA, and results are typical of 3 similar experiments. (C) Endocytic activity of immature (▪) and mature (□) MDDCs was assessed. MDDCs, previously cultured for 24 hours in the absence or presence of either LPS or anti-CD2, were cultured with FITC-dextran for 30 minutes, and the amount of probe internalized was measured by FACS analysis. Expression indices for samples were determined, and data are presented as mean ± SEM. Findings were representative of 3 similar experiments.