Fibronectin and the adhesive properties of rat lymphocytes obtained from different peripheral lymphoid tissues

A comparative investigation has been carried out on the effect of plasma fibronectin (Fn) on the adhesive properties of normal rat lymphocytes obtained from different lymphoid tissues: blood, spleen, mesenteric and tonsillar lymph nodes. Fn was immobilized on the basis of its ability to bind to gelatin. We established that concentrations of 40-50 micrograms/ml are sufficient for a saturation effect on Fn coating. For spleen cells an adhesion of 55.7 +/- 9.3%, for mesenteric lymph nodes 34.5 +/- 8.7% and for tonsillar cells 33.8 +/- 3.2% was observed. Blood lymphocytes showed the lowest adhesion, 21.3 +/- 4.2%. Compared to the other lymphoid tissues, the spleen cells exhibited a "basal" adherence to surfaces coated with gelatin only: 19.2 +/- 4.1%. T lymphocytes participate to a greater extent in the process, since their number was significantly reduced in cell suspensions after adhesion to both gelatin and gelatin-Fn coated surfaces. The addition of soluble Fn leads to a competitive inhibition of the lymphocyte adhesion to gelatin-Fn coated surfaces. The data demonstrated the important role of Fn for the adhesive interactions of lymphocytes during their functional distribution in the tissues.