Unresponsiveness of Mixed Leucocyte Cultures from Thymectomized Adult Dogs

Abstract

THE mixed leucocyte culture test¹ has been modified and adopted for the dog in our laboratory. When peripheral blood leucocytes from two unrelated people are mixed in culture for several days (the untreated cells from one individual acting as the responding population, and the mitomycin treated cells from the second individual acting as a stimulation population) a proliferative response occurs which is characterized by an increase in DNA synthesis. The same type of response seems to occur in the dog. In man and the dog, the response seems to be related to the ability of one population of cells to recognize an immunogenetic difference in the second population of cells. Lack of reactivity in this test is interpreted as meaning that two populations of cells lack immunogenetic disparity or cannot recognize the existing disparity. If the antigens of the lymphocytes are similar to those present in other organs, lack of reactivity in mixed leucocyte culture tests might lead to the prediction of long term allograft survival. This hypothesis, although incompletely tested, seems to be true of human and dog kidney transplants (unpublished results).