Characteristics of the immunosuppressive activity of lymphoid organ cells in the process of sensitization with ram erythrocytes and exposure to antilymphocyte serum

In the adoptive transfer of cells obtained from the thymus, lymph nodes and the spleen to intact syngeneic animals the suppression of immune response was induced by lymph node cells. If the donors were previously sensitized, the cells of the thymus and lymph nodes showed suppressive activity in the adoptive transfer test. A single injection of antilymphocytic serum to the donors of lymphoid cells, previously sensitized with sheep red blood cells, enhanced the immunosuppressing action of thymocytes and lymph node cells.