Figure 5.

Functional characterization of 1D8^N/CCEA.1 trimerbody. Adhesion of HEK293 cells (A) and HEK293^m4−1BBcells (B) to plastic-immobilized BSA or CEA, after incubation with purified 1D8^N18 or 1D8^N/CCEA.1 trimerbodies. Adhesion of HEK293 cells and HEK293^m4−1BB cells to plastic-immobilized laminin 111 (Lm111) was used as a control (C). Data are plotted as the fold change in adhesion relative to BSA. Costimulatory activity of anti-4-1BB antibodies (D,E). Mouse CD8a+ T cells were plated with immobilized anti-CD3 mAb and hCEA or BSA in the presence of 1D8 IgG, 1D8^N18, or 1D8^N/CCEA.1, and proliferation (D) and IFN-γ secretion (E) were determined after 48 h. All the results are representative of one of three independent experiments. Data are mean ± SD (n = 3), *P < 0.05, **P ≤ 0.01, Student's t-test.