The migration of lymphocytes across specialized vascular endothelium. VI. The migratory behaviour of thoracic duct lymphocytes retransferred from the lymph nodes, spleen, blood, or lymph of a primary recipient.

Thoracic duct lymphocytes labelled with 51Cr were injected into a primary recipient and then were transferred for a second time from the lymph nodes (cervical and/or mesenteric), spleen, lymph, or blood into a series of final recipients. Measurement of the organ distribution of labelled lymphocytes in the final recipients enabled three main conclusions to be drawn. (1) Lymphocytes that had localized in the spleen, mesenteric lymph nodes (LN), or cervical LN of the first recipient showed no tendency to return in increased numbers to the same organ in the final recipient. (2) Lymphocytes that had recently entered the spleen or LN were temporarily impaired in their ability to reenter LN. This capacity was recharged when the cells returned to the lymph and the blood. (3) Lymphocytes that had been passaged from blood to lymph and collected for up to 4 hr at room temperature entered the LN of a recipient much faster than did nonpassaged thoracic duct lymphocytes collected overnight at 0 degree C. Supplementary experiments indicated that the different migratory behavior of thoracic duct lymphocytes under these two circumstances was mainly a consequence of their handling in vitro during the collecting and the labelling procedures. This functional impairment was not associated with a diminished ability to enter the spleen and bone marrow or to survive in recipients for up to 24 hr.