3H-uridine incorporation as a T lymphocyte indicator in the rat

Abstract

Although about 70% of rat thoracic duct small lymphocytes labeled readily in vitro with 3H-uridine, only 3–38% of peritoneal exudate lymphocytes labeled. Since exudate cells are mostly B lymphocytes, 3H-uridine in concentrations used were presumed to label the T lymphocyte. Percentages of small lymphocytes that labeled in cell suspensions from various tissues were consistent with other estimates of T cells in those sources: 74.7% in thoracic duct, 70.2% in blood and 65.6% in spleen. When lymphopenia was induced by polyethylene 32P strips applied to the spleen, a procedure that depletes mostly small recirculating lymphocytes, both labeled (T) and nonlabeled (B) cells were depleted in similar time sequence. Both cell types recovered at a similar rate after the spleen strips were removed. Induction of peritoneal inflammation by PPD in tubercle-bacilli immune rats caused an enhanced lymphocytic exudation but no increase in percentage of labeled (T) lymphocytes. The defect in 3H-uridine incorporation that characterizes the rat B lymphocyte seemed to be relatively specific for that RNA precurser; 3H-cytidine labeled the majority of lymphocytes in peritoneal exudate.