Specific antisera against recirculating and non-recirculating lymphocytes in the rat.

Heterologous anti-lymphocyte sera were prepared by injecting suspensions of recirculating or non-recirculating lymphocytes into rabbits. Recirculating lymphocytes were obtained from a thoracic duct fistula, and non-recirculating lymphocytes were obtained from the blood of rats in which thoracic duct lymph had been drained away for 3 days. The cytotoxic activity of the sera was assayed by measuring the isotope release from target cells labelled with Cr. Antibodies specific for recirculating or non-recirculating lymphocytes could be demonstrated with the aid of cell adsorption techniques. Cell-specific sera were used to estimate the proportion of recirculating and non-recirculating lymphocytes in lymphocyte suspensions obtained from thymus lymph nodes, blood and bone marrow. All thymocytes and most of the lymph node lymphocytes appeared to have antigenic properties in common with recirculating lymphocytes, whereas about 20% of the blood lymphocytes and most of the bone marrow lymphocytes belonged to the non-recirculating lymphocyte antigenic type.