Migration Pattern of Splenic Lymphocytes after Local Labelling of the Pig Spleen with ³H‐Cytidine

Abstract

In normal young pigs splenic lymphocytes were selectively labelled by injecting tritiated cytidine into a splenic artery. 10 h later several lymphoid and non-lymphoid organs were investigated for spleen-derived lymphocytes by autoradiography. The relative and absolute organ distribution of the labelled cells was determined. Labelled lymphocytes appeared rapidly in the peripheral blood reaching a mean labelling index of 4.8%. More splenic lymphocytes were found in thymus dependent areas than in thymus independent areas of lymphoid organs. Nearly 40% of all emigrated lymphocytes homed to lymph nodes and only about 1% in the thymus. A surprisingly high number of splenic lymphocytes were located in the bone marrow and the lung.