The cytotoxic activity of lymphocytes from human lymph in vitro.

The cytotoxicity and DNA synthesis of thoracic duct and blood lymphocytes from four patients have been studied on the 1st day of drainage. Three patients were being drained as a pretreatment for kidney transplantation and one had myasthenia gravis. In one patient lymphocytes were obtained from a lymphatic fistula in the groin and from the blood 5 weeks after drainage began. Lysis of tissue culture cells (Chang cells) in the presence of PHA or antiserum to target cell antigens was quantitated by [Cr]chromate release. Lymphocytes from lymph were at best poorly cytotoxic to antibody-treated target cells under conditions where purified blood lymphocytes from the same donors had normal lytic activity. PHA-induced cytotoxicity by lymph-borne lymphocytes was noted but was considerably weaker than that of blood lymphocytes. In contrast, incorporation of [C]thymidine into DNA of thoracic duct lymphocytes after stimulation with PHA was about 60% of that of the patients' blood lymphocytes. The DNA synthesis of thoracic duct lymphocytes induced by PPD or allogeneic lymphocytes was as good as that of blood lymphocytes. The mitotic response to PHA by lymphocytes from the lymph was reduced after two weeks drainage. It is assumed that the number of effector cells and/or supporting cells in antibody-induced cytotoxicity in thoracic duct lymph is too small to induce target cell lysis under the present experimental conditions. Moreover, our data indicate that PHA-induced and antibody-mediated cytotoxicity are at least partly mediated by different lymphocyte subpopulations.