Figure 1.

Cells expressing α4β1 but not α5β1 integrin bind to recombinant ADAM12 disintegrin domain. (A and B) CHOB2-α4 (black) and CHOB2-α5 (gray) cells were resuspended in Puck's saline A containing 0.5 mM Ca²⁺ and 0.5 mM Mg²⁺, pretreated with either no antibody, 5 μg/ml anti-α4 antibody (HP2/1), or 5 μg/ml anti-α5 antibody (CBL497) for 30 min, and then added to wells coated with 5 μg/ml ADAM12 disintegrin domain (A) or 5 μg/ml human plasma fibronectin (B). Cells were allowed to bind to coated wells for 1 h. After three washes, adherent cells were stained with crystal violet and solubilized with 1% SDS. Optical density of the wells at 595 nm was then read with a microplate reader. (C and D) CHO-α4/GFP (black) and CHOK1 cells (white) were pretreated with either no antibody or 5 μg/ml anti-α4 antibody (HP2/1) for 30 min before adding to wells coated with 5 μg/ml ADAM12 disintegrin domain (C) or human plasma FN (D). Adhesion assays were then conducted as described above. These experiments were repeated three times with similar results.