Interaction of thymus lymphocytes with histoincompatible cells. II. Recirculating lymphocytes derived from antigen-activated thymus cells

Abstract

Thoracic duct cannulation of irradiated F 1 recipients of parental thymus or thoracic duct lymphocytes revealed that, soon after cell injection, only small numbers of thoracic duct lymphocytes (TDL) emerged. By the use of specific antisera, these cells were shown to consist almost entirely of radio-resistant host lymphocytes. The number of cells collected declined to reach very low levels by 3 1 2 days. In a syngeneic situation no further cells appeared but in a semi-allogeneic system, large numbers of cells subsequently emerged, of which 60–80% were pyroninophilic blasts and 95% had recently incorporated tritiated thymidine. It was shown with appropriate antisera that 95–100% of these cells were derived from the original inoculated lymphocytes and had the characteristic features of T lymphocytes. They were thus christened T.TDL. TDL were 25 times more effective in the production of T.TDL than were thymus cells. No difference could be demonstrated in the properties of these lymphocytes, whether derived by activation of thymus cells or of TDL. They were just as capable of recirculating as normal TDL when injected into syngeneic mice. Unlike TDL, however, they showed a greater propensity to localize in the gut wall than in the mesenteric lymph nodes. The technique described here may be extended to other antigenic systems to allow recovery of purified populations of T cells activated to various defined antigens.