title: Synergy during in vitro cytotoxic allograft responses. I. Evidence for cell interaction between thymocytes and peripheral T cells.
abstract: A mouse in vitro allograft system was used to evaluate the concept of T-T interaction in T cell-mediated cellular immunity. In analyzing the responsiveness of thymus-processed lymphocytes as obtained from different tissues, a heretogeneity within T cells was found in regard to their capacity to be immunized in vitro against transplantation antigens. Recirculating T cells were 10-20-fold superior to thymocytes, splenic T cells being intermediate. When few (1.5 x 10(6)) peripheral T cells, in numbers too small to yield good cytotoxic responses, were mixed with 14 x 10(6) thymocytes and the cell mixture immunized in vitro against cell-bound alloantigens, cytotoxic activity was generated exceeding about 10-20-fold the values that could be explained by a pure additive effect. Synergy occurred also in a mixture of responder T cells derived from CBA (H-2(k)) and AKR (H-2(k)) mice. Thus AKR anti-phi C3H serum could be used for discriminating between thymus-derived and peripheral T cell-derived cytotoxic lymphocytes (CL). Cytotoxic activity produced during the synergistic interaction between thymocytes and peripheral T cells was about 70% T cell derived, the remainder being thymus derived. The synoptic interpretation of this finding and "limiting dilution" experiments of the responder cells suggested strongly that peripheral T cells provide the major source for precursor cells of CL, thymocytes acting mainly as helper (amplifier) cells.
mesh_terms: D000818:Animals; D003601:Cytotoxicity Tests, Immunologic; D005260:Female; D006649:Histocompatibility Antigens; D007111:Immunity, Cellular; D007519:Isoantigens; D051379:Mice; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D014184:Transplantation, Homologous
chemical_list: D006649:Histocompatibility Antigens; D007519:Isoantigens