QUANTITATIVE ASPECTS OF THE RECIRCULATION OF LYMPHOCYTES; AN ANALYSIS OF DATA FROM EXPERIMENTS ON SHEEP

¹ Department of Experimental Pathology, John Curtin School of Medical Research, Australian National University, Canberra and the A.R.C. Institute of Animal Physiology, Babraham, Cambridge

By cannulating the efferent ducts of each of twenty popliteal lymph nodes in merino ewes it was possible to collect the lymph and thus measure the outputs of lymphocytes from these nodes for periods of over 100 hr., under physiological conditions.

A linear correlation between the weight of a lymph node and its output of lymphocytes was demonstrated. Although the statistical significance of this correlation was low, predictions based upon it agreed with the observed results of other investigations. It was therefore concluded that on average, in adult sheep, a lymph node weighing 1 g. discharges 30 million lymphocytes/hr. into the efferent lymph. It was shown that lymphocytes from the afferent lymph and de novo production within the node make only a small contribution to this number. Most of the lymphocytes in the efferent lymph must be supplied therefore directly from the blood which flows through the node.

Measurements of the venous outflow from individual prefemoral nodes in anæsthetized Clun Forest sheep showed that the blood flow through lymph nodes is of the order of 1 ml./min./g. node wt. Using this value it was calculated that some 12 per cent of the lymphocytes in the blood flowing through a node must leave the blood, pass through the substance of the node and enter the efferent lymph.

Note:

Part of the work done at Babraham was carried out during the tenure of a Beit Memorial Medical Research Fellowship supported by a travel grant from the Wellcome Foundation.

The techniques used for collecting lymph from unanæsthetized sheep were introduced and developed by Dr. Bede Morris of the Australian National University and I thank him for instructing me in their use.