Cellular interaction between human lymphoid cells and RA-SNC77 cells. (a) Adhesion between lymphoid cell lines and RA-SNC77. Biscarboxyethyl carboxyfluorescein-labeled lymphoid cells (2 × 105 cells/well) were plated onto a monolayer of RA-SNC77 cells (1 × 104 cells/well) in a 96-well flat-bottomed culture plate. After 30 min of coculture, the nonadherent cells were removed and the fluorescence intensity of the adherent cells was measured. Results are expressed as the means ± standard deviation of three different experiments. (b) Transmigration of lymphoid cell lines underneath RA-SNC77 cells. RA-SNC77 cells (2 × 104 cells/well) were cultured for 2 days in a 12-well culture plate. Lymphoid cells (1 × 106 cells/well) were plated onto a monolayer of RA-SNC77 cells and incubated for 2 hours. The lymphoid cells bound to the surface of the RA-SNC77 cells were removed, and the interaction between these cells was examined with a phase-contrast microscope. RA-SNC77 cells holding more than three lymphoma cells beneath them were defined as positive for transmigration. At least 200 RA-SNC77 cells were counted in each experiment. Results are expressed as the percentage of positive cells to total cells. Values are the means ± standard deviation of three different experiments.