Controlled cell deformation produces defined areas of contact between cells and ligand-coated surfaces

A method which allows precise control of the time of initiation and the area of contact of T cells with immobilized ligands has been developed. Cells are trapped in an asymmetric film that can be quantitatively thinned by reducing the film's capillary pressure. Ligands adsorbed to the base of the apparatus are forced into close contact with the cells as the air-liquid interface is drawn down. Using interference microscopy and microbeads to indicate the film height, the amount of thinning can be controlled to within 1 microm. In this study, this system was used to produce contact areas of 182 and 356 microm2 between T cells and anti-CD3 coated surfaces. These contact areas were measured using fluorescent dye exclusion microscopy. This apparatus can be used for quantitative studies of T cell activation, as is reported in Patrick et al., J. Immunol. Method. 24:97-108, 2000.