Fig. 4.

Ipilimumab is ineffective in blocking B7-trans-endocytosis by CTLA-4. a FACS profiles of B7-2-GFP-transfected or CTLA-4-OFP-transfected CHO cell lines used for trans-endocytodosis assay. b Rapid trans-endocytosis of B7-2 by CTLA-4. B7-2-GFP transfectants and CTLA-4-OFP transfectants were co-incubated for 0, 0.5, 1 and 4 h at 37 °C. c Lack of trans-endocytosis of B7-H2 by CTLA-4. As in b, except that B7-H2-GFP-transfected P815 cells and data at 0, 1 and 4 h of co-culturing are presented. d Representative profiles depicting differential blockade of trans-endocytosis of B7-1-GFP by CTLA-4-OFP-expressing CHO cells during coculture in the presence of control hIgG-Fc or Fab from either Ipilimumab or L3D10 (10 μg/ml) for 4 h. e Dose–response curve depicting inhibition of B7-1 trans-endocytosis by L3D10 and Ipilimumab Fab. As in d, except varying doses of control hIgG-Fc or Fab were added to the co-culturing. f As in d, except that B7-2-GFP-transfected CHO cells were used. g Dose–response curve depicting inhibition of B7-2 trans-endocytosis by L3D10 and Ipilimumab Fab. As in e, except that B7-2-GFP-transfected CHO cells were used. Data shown (mean ± S.D.) are % of trans-endocytosis over varying doses of Fab. All assays have been repeated at least three times