Relationship between the recirculation of lymphocytes and protein concentration of lymph in sheep

The concentration and output of lymphocytes in lymph from the popliteal node in sheep were varied by antigenic stimulation of the lymph node and by intravenous administration of bovine anti-lymphocyte serum (ALS). The 4-5-fold increase in output and concentration of lymphocytes in lymph following antigenic stimulation of the node was accompanied by a 25-35% increase in the concentration of total protein and albumin. The above changes were not observed in afferent lymph draining the site of antigen injection. There was a 75-80% decrease in concentration of lymphocytes in lymph from the unstimulated popliteal lymph node following the administration of ALS and this was accompanied by decreases of 10-35% in the concentration of albumin and immunoglobulin. Essentially the same changes were observed when ALS was administered 6 days after antigenic stimulation of the node. Administration of ALS to sheep with cannulated intestinal lymphatic ducts was followed by a 75-80% reduction in lymphocyte concentration and in decreases ranging from 12-50% in the concentration of albumin, IgM and IgG-2. It is suggested that a significant loss of plasma protein is associated with the migration of lymphocytes between the endothelial cells of the post-capillary venules in lymph nodes.