Rate of production of P32-labeled lymphocytes.

E BULK OF DATA initially accumulated regarding the lymphocyte tended to indicate that its life span was relatively short. Thus, Minot and Isaacs,’ in 1925, transfused blood from a patient with chronic lymphocytic leukemia into a patient with lymphosarcoma. The recipient’s blood showed an elevated lymphocyte count for 35 minutes before returning to normal. Yoffey,2 in 1935, showed that in the dog, lymphocytes remained in the blood only from 11 to 12 hours. Adams, Saunders and Lawrence, in 1945, demonstrated a 10 to 12 hour rate of utilization for the lymphocyte in the cat. Weisberger et al.,4 found that the white counts of rats injected with rat lymphocytes tagged with p32 returned to normal in a matter of minutes. However, in spite of this earlier work, investigators more recently have concluded that the blood life span of the lymphocyte may be much longer. Thus, Osgood,5 using the technic of P32-labeling of white blood cells with subsequent DNA extraction, estimated the life span of lymphocytes in chronic lymphocytic leukemia to he about 30 days. Christensen and Ottesen#{176} thought that the majority of lymphocytes in the blood have a mean age of 100 to 200 days. A minority of the lymphocytes have a mean age of three days. In chronic lymphocytic leukemia Doering and his co-workers7 observed maximum lymphocyte DNA-P32 activity after 14 to 15 days. These important observations, however, become very puzzling when one considers the fact that the thoracic duct outptmt of lymphocytes is alone sumfficient to replace the circulating blood lymphocytes one or more times depending on the animal.2’3’8 ’2 The work reported here was undertaken in an attempt to clarify this problem as well as to study the rate of production and appearance of labeled lymphocytes in the thoracic duct.