Fig. 8. Inhibition of thymocyte adhesion to thymic epithelial cells by function-blocking antibodies to integrin _E and E-cadherin. (A,B) The micrographs show adhesive interactions of MACS-isolated CD8⁺ thymocytes with primary thymic epithelial cells in the absence (A) or presence (B) of anti-CD103 antibodies. Without antibody treatment, the small, round and darkly stained thymocytes adhered strongly to the adherent epithelial cells. By contrast, anti-CD103 treatment strongly diminished thymocyte adhesion. Bar, 100 µm. (C) Thymocyte cell adhesion to thymic epithelial cells was quantified after BCECF-labelling of CD8⁺ thymocytes. Fluorescence intensity of the labelled cells used for the cell adhesion assay was set to 100% (lane 1). Around 40% of the CD8⁺ thymocytes attached to the adherent thymic epithelial cell layer (lane 2). The adhesion process was not influenced by addition of the W6/32. HL control antibody (lane 3). (D) Adhesive interactions of CD8⁺ thymocytes with thymic epithelial cells were inhibited by antibodies against E-cadherin and CD103. Fluorescence intensity of cell binding in the absence of the antibodies was set to 100% (lane 1). Both anti-E-cadherin (lane 2) and anti-CD103 (lane 3) antibodies diminished cell binding to 30-40%. Combined addition of both antibodies did not show an enhanced inhibitory effect (lane 4).