Cellular and humoral factors governing canine mixed lymphocyte cultures after renal transplantation: II. Cellular

Mixed lymphocyte culture (MLC) reactivity has been followed in dogs before, during, and after rejection of heterotopically transplanted kidney allografts. During the time of active rejection, there was a loss of cellular reactivity in recipient (R) peripheral blood which could be ascribed to entrapment of immunoreactive cells in the rejecting kidneys. In this period, lymphocytes removed from blood draining the allograft had diminished MLC reactivity when compared to samples obtained from normal venous and arterial blood. Lymphocytes recovered from the rejecting organ demonstrated an accelerated MLC responsiveness to stimulating donor (D) lymphocytes at a time when lymphocytes from peripheral blood had diminished reactivity. Similar reactivity with kidney lymphocytes was also seen using stimulating lymphocytes of indifferent (I) dogs. Following rejection, when MLC responsiveness returned, a state of increased immunity could be demonstrated by an acceleration in the onset of reactivity after incubation in culture for shorter time periods.