Interactions between heterochronic cells in the formation of delayed-type hypersensitivity

The effect of ageing on lymphocyte and macrophage functional activity in the induction of tuberculin sensitivity was studied in experiments on 440 CBA mice of three age groups. The capacity of old animals to generate delayed-type hypersensitivity following administration of BCG cells was found to be diminished and their lymphocytes caused decreased hypersensitivity on transplantation. The capacity of recipients to reproduce delayed-type hypersensitivity after thymocyte and bone marrow cell transplantation was influenced by the age of transplanted thymocytes. This capacity was markedly suppressed on the recipients of old cells. The antigen presentation function of macrophage did not after significantly as a function of age.