Control of cell locomotion: perturbation with an antibody directed against specific glycoproteins

A murine monoclonal antibody, SLOW-1, was selected, which inhibits the locomotion of chick embryo fibroblasts (the immunizing cells) in tissue culture. The antibody, an IgM, cross-reacts in locomotion assays with a number of tumor and untransformed cells, and on fixed and permeabilized cells binds 1-5 X 10(5) target sites with an affinity of 10(-8) M. The antigen can be extracted from cells with isotonic buffers containing EGTA, binds to Concanavalin A, and when analyzed on SDS gels by immunoblotting, two major antigenic glycoproteins are detected at 57 kd (isoelectric point, 5.1) and at 44 kd (isoelectric point, 5.4). The antigenic site involves galactosyl or mannosyl residues, or both, within a complex, N-linked carbohydrate tree. The possible contribution of the SLOW-1 antigen to a common control system of locomotion operating over the cell surface is discussed.