Circulation and migration of small blood lymphocytes in the rat. I. Kinetics of lymphocyte circulation in the lymphoid organs.

Seventy male Wistar rats were the recipients of labeled small lymphocytes (1.5 X 10(7) each) collected from the peripheral blood of syngeneic donors. The migrating labeled lymphocytes were traced in the various organs 1 to 60 minutes following their transfusion. Lymphoid organs and liver were processed for extraction of labeled nucleotides and for radioactivity assay. The purpose of this work was to study the dynamics of the circulation of the small lymphocytes between blood and lymphoid system. This study was done before equilibrium between these two compartments was reached. The result of this work showed that the small blood lymphocytes recirculate continuously between peripheral blood and the lymph node with duration less than 3 minutes per cycle. In a lymph node, this circulation is 80 times more efficient than the circulation via the thoracic duct lymph.