RESDECs lead to more rapid tumor growth and form vessels in tumors. (A) 1 × 106 RESDEC cells (○), 1 × 106 C755 tumor cells (▵), or 1 × 106 of each cell type (□) were injected subcutaneously in SCID mice. Tumors developed earlier in mice coinjected with both cell types. RESDECs alone do not form detectable tumors. Five mice were injected in each group and similar results were obtained in 2 independent experiments. Error bars represent standard deviation of tumor diameter measurements for each group. The asterisk labels time points with statistically significant (P < .01) increased tumor growth at the indicated time point. (B) Hematoxylin and eosin–stained section of C755 tumor coinjected with RESDECs to demonstrate vascularity. (C) C755-derived tumor without coinjection of RESDECs stained for anti–HLA class I antibody that cross reacts with rhesus, but not mouse cells. Minimal staining demonstrates lack of RESDEC-derived vessels. (D) C755 tumor coinjected with RESCDECs stained for anti–HLA class I antibody demonstrates tumor vessels derived from RESDECs. (E) Isotype control (IgG2a) staining of same C755 tumor coinjected with RESDECs as in panel D. Original magnifications: × 200 (B); × 400 (C-E)
