(A) Dose-related motility response of Sc-1 cells to intact fibronectin, 110-kD polypeptide, or 38-kD fragment under the chemoattractive stimuli of IL-1β/IL-2, as monitored FATIMA (see Materials and Methods). (B) IL-1β/IL-2–elicited chemotaxis of Sc-1 cells on intact fibronectin (10 μg/mL), 120-kD polypeptide, or 38-kD fragment (20 μg/mL) in the presence of antibodies to 4 (HP2-1 and PS2), β1 (4B4), or 4β7 (Act-1) integrins, added at their maximal inhibitory concentration. (C) Effects of antibodies against the central cell-binding domain of fibronectin on IL-1β/IL-2–induced Sc-1 cell chemotaxis. The membrane to be transmigrated was coated with the 110-kD polypeptide (20 μg/mL) followed by incubation with the different antibodies as described for CAFCA. FN15 corresponds to a cell-binding domain-directed MoAb with no reported functional effects.