INHIBITION OF THE MULTIDRUG EFFLUX PUMP IN ISOLATED HEPATOCYTE COUPLETS BY IMMUNOSUPPRESSANTS FK506 AND CYCLOSPORINE

Abstract

The frequency of isolated low-density graft-infiltrating cells (GIC) secreting IFN-γ, IL-6, and IL-10 was studied in 8 cases of irreversible rejection of human renal allografts, using ELISA and SPOT-forming cells (ELISPOT) assays. The GIC were mostly CD8+ T cells, although CD4+ T cells, B cells, and macrophages could also be detected. On the average, in 106 cells, 189 secreted IFN-γ, 747 IL-10, and 17114 IL-6. Culture of GIC in the presence of IL-2 resulted in an increase in the frequency of IFN-γ-producing cells (IFN-γ-PC), in a dose-dependent manner, with an optimal 6.5-fold increase at 50 U/ml. In contrast, 25 U/ml IL-4 decreased the frequency of spontaneous and IL-2-induced IFN-γ-PC by 71.3% and 52.8%, respectively. Furthermore, IL-4 reduced the frequency of IL-6-PC (56.8%). By this new approach to graft rejection, it becomes easier to determine cytokine profiles within an allograft and to study their modulation by different agents. It could be a useful model of study for the development of new treatment.